Add simple expressions and equations

2024-10-10 19:44:29 +03:00 · 2024-10-10 19:44:29 +03:00 · 3f09d20465
commit 3f09d20465
parent 89d78c43bb
55 changed files with 2392 additions and 0 deletions
--- a/controls-constructor/build.gradle.kts
+++ b/controls-constructor/build.gradle.kts
@ -16,10 +16,13 @@ kscience{
    useSerialization()
    commonMain {
        api(projects.controlsCore)
+        implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.8.1")
+        implementation("org.jetbrains.kotlinx:multik-core:0.2.3")
    }

    commonTest{
        implementation(spclibs.logback.classic)
+        implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.8.1")
    }
 }

--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/Annotation.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/Annotation.kt
@ -0,0 +1,9 @@
+package space.kscience.controls.constructor.dsl.core
+
+/**
+ * Класс для представления аннотации.
+ */
+public data class Annotation(
+    val name: String,
+    val properties: Map<String, Any>
+)
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/EquationSystem.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/EquationSystem.kt
@ -0,0 +1,196 @@
+package space.kscience.controls.constructor.dsl.core
+
+import space.kscience.controls.constructor.dsl.core.equations.*
+import space.kscience.controls.constructor.dsl.core.expressions.*
+import space.kscience.controls.constructor.dsl.core.variables.ArrayVariable
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Класс для хранения и обработки системы уравнений.
+ */
+public class EquationSystem {
+    public val equations: MutableList<EquationBase> = mutableListOf()
+    public val variables: MutableSet<String> = mutableSetOf()
+    public val derivativeVariables: MutableSet<String> = mutableSetOf()
+    public val algebraicEquations: MutableList<Equation> = mutableListOf()
+    public val initialEquations: MutableList<EquationBase> = mutableListOf()
+    public val conditionalEquations: MutableList<ConditionalEquation> = mutableListOf()
+
+    /**
+     * Метод для добавления списка уравнений.
+     */
+    public fun addEquations(eqs: List<EquationBase>) {
+        for (eq in eqs) {
+            addEquation(eq)
+        }
+    }
+
+    /**
+     * Метод для добавления одного уравнения.
+     */
+    public fun addEquation(eq: EquationBase) {
+        equations.add(eq)
+        collectVariables(eq)
+    }
+
+    private fun collectVariables(eq: EquationBase) {
+        when (eq) {
+            is Equation -> {
+                collectVariablesFromExpression(eq.leftExpression)
+                collectVariablesFromExpression(eq.rightExpression)
+
+                // Classify the equation
+                if (isDifferentialEquation(eq)) {
+                    // Handled in toODESystem()
+                } else {
+                    algebraicEquations.add(eq)
+                }
+            }
+            is ConditionalEquation -> {
+                collectVariablesFromExpression(eq.condition)
+                collectVariables(eq.trueEquation)
+                eq.falseEquation?.let { collectVariables(it) }
+                conditionalEquations.add(eq)
+            }
+            is InitialEquation -> {
+                collectVariablesFromExpression(eq.leftExpression)
+                collectVariablesFromExpression(eq.rightExpression)
+                initialEquations.add(eq)
+            }
+            else -> {
+                throw UnsupportedOperationException("Unknown equation type: ${eq::class}")
+            }
+        }
+    }
+
+    private fun collectVariablesFromExpression(expr: Expression) {
+        when (expr) {
+            is VariableExpression -> variables.add(expr.variable.name)
+            is ConstantExpression -> {
+                // Constants do not contain variables
+            }
+            is DerivativeExpression -> {
+                collectVariablesFromExpression(expr.variable)
+                derivativeVariables.add(expr.variable.variable.name)
+            }
+            is PartialDerivativeExpression -> {
+                collectVariablesFromExpression(expr.variable)
+                collectVariablesFromExpression(expr.respectTo)
+                // For partial derivatives, variables may need special handling
+            }
+            is BinaryExpression -> {
+                collectVariablesFromExpression(expr.left)
+                collectVariablesFromExpression(expr.right)
+            }
+            is FunctionCallExpression -> {
+                expr.arguments.forEach { collectVariablesFromExpression(it) }
+            }
+            is ArrayVariableExpression -> {
+                collectVariablesFromArrayVariable(expr.left)
+                collectVariablesFromArrayVariable(expr.right)
+            }
+            is ArrayScalarExpression -> {
+                collectVariablesFromArrayVariable(expr.array)
+                collectVariablesFromExpression(expr.scalar)
+            }
+            else -> {
+                throw UnsupportedOperationException("Unknown expression type: ${expr::class}")
+            }
+        }
+    }
+
+    private fun collectVariablesFromArrayVariable(arrayVar: ArrayVariable) {
+        variables.add(arrayVar.name)
+        // Additional processing if necessary
+    }
+
+    private fun isDifferentialEquation(eq: Equation): Boolean {
+        val leftIsDerivative = containsDerivative(eq.leftExpression)
+        val rightIsDerivative = containsDerivative(eq.rightExpression)
+        return leftIsDerivative || rightIsDerivative
+    }
+
+    private fun containsDerivative(expr: Expression): Boolean {
+        return when (expr) {
+            is DerivativeExpression -> true
+            is BinaryExpression -> containsDerivative(expr.left) || containsDerivative(expr.right)
+            is FunctionCallExpression -> expr.arguments.any { containsDerivative(it) }
+            else -> false
+        }
+    }
+
+    /**
+     * Подготовка системы ОДУ для численного решения.
+     */
+    public fun toODESystem(): ODESystem {
+        val odeEquations = mutableListOf<ODEEquation>()
+
+        // Process equations to separate ODEs and algebraic equations
+        for (eqBase in equations) {
+            when (eqBase) {
+                is Equation -> {
+                    val eq = eqBase
+                    if (isDifferentialEquation(eq)) {
+                        // Handle differential equations
+                        processDifferentialEquation(eq, odeEquations)
+                    } else {
+                        // Handle algebraic equations
+                        algebraicEquations.add(eq)
+                    }
+                }
+                is ConditionalEquation -> {
+                    // Handle conditional equations
+                    // For ODE system, we might need to process them differently
+                    conditionalEquations.add(eqBase)
+                }
+                is InitialEquation -> {
+                    // Initial equations are used for setting initial conditions
+                    initialEquations.add(eqBase)
+                }
+                else -> {
+                    throw UnsupportedOperationException("Unknown equation type: ${eqBase::class}")
+                }
+            }
+        }
+
+        return ODESystem(odeEquations, algebraicEquations, initialEquations, conditionalEquations)
+    }
+
+    private fun processDifferentialEquation(eq: Equation, odeEquations: MutableList<ODEEquation>) {
+        // Identify which side has the derivative
+        val derivativeExpr = findDerivativeExpression(eq.leftExpression) ?: findDerivativeExpression(eq.rightExpression)
+        if (derivativeExpr != null) {
+            val variableName = derivativeExpr.variable.variable.name
+            if (derivativeExpr.order != 1) {
+                throw UnsupportedOperationException("Only first-order derivatives are supported in this solver.")
+            }
+
+            val rhs = if (eq.leftExpression is DerivativeExpression) eq.rightExpression else eq.leftExpression
+            odeEquations.add(ODEEquation(variableName, rhs))
+            derivativeVariables.add(variableName)
+        } else {
+            throw UnsupportedOperationException("Equation is marked as differential but no derivative found.")
+        }
+    }
+
+    private fun findDerivativeExpression(expr: Expression): DerivativeExpression? {
+        return when (expr) {
+            is DerivativeExpression -> expr
+            is BinaryExpression -> findDerivativeExpression(expr.left) ?: findDerivativeExpression(expr.right)
+            is FunctionCallExpression -> expr.arguments.mapNotNull { findDerivativeExpression(it) }.firstOrNull()
+            else -> null
+        }
+    }
+}
+
+public data class ODEEquation(
+    val variableName: String,
+    val rhs: Expression
+)
+
+public class ODESystem(
+    public val odeEquations: List<ODEEquation>,
+    public val algebraicEquations: List<Equation>,
+    public val initialEquations: List<EquationBase>,
+    public val conditionalEquations: List<ConditionalEquation>
+)
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/Record.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/Record.kt
@ -0,0 +1,19 @@
+package space.kscience.controls.constructor.dsl.core
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Класс для представления записи (record).
+ */
+public class Record(public val name: String) {
+    public val fields: MutableMap<String, Variable> = mutableMapOf()
+
+
+    public fun field(name: String, unit: PhysicalUnit) {
+        if (fields.containsKey(name)) {
+            throw IllegalArgumentException("Field with name $name already exists in record $name.")
+        }
+        fields[name] = Variable(name, unit)
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/algorithms/AlgorithmBuilder.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/algorithms/AlgorithmBuilder.kt
@ -0,0 +1,37 @@
+package space.kscience.controls.constructor.dsl.core.algorithms
+
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Класс для построения алгоритмов.
+ */
+public class AlgorithmBuilder {
+    public val statements: MutableList<Statement> = mutableListOf()
+
+    public fun assign(variable: Variable, expression: Expression) {
+        statements.add(AssignmentStatement(variable, expression))
+    }
+
+    public fun ifStatement(condition: Expression, init: AlgorithmBuilder.() -> Unit) {
+        val trueBuilder = AlgorithmBuilder()
+        trueBuilder.init()
+        statements.add(IfStatement(condition, trueBuilder.build(), null))
+    }
+
+    public fun forStatement(variable: Variable, range: IntRange, init: AlgorithmBuilder.() -> Unit) {
+        val bodyBuilder = AlgorithmBuilder()
+        bodyBuilder.init()
+        statements.add(ForStatement(variable, range, bodyBuilder.build()))
+    }
+
+    public fun whileStatement(condition: Expression, init: AlgorithmBuilder.() -> Unit) {
+        val bodyBuilder = AlgorithmBuilder()
+        bodyBuilder.init()
+        statements.add(WhileStatement(condition, bodyBuilder.build()))
+    }
+
+    public fun build(): Algorithm {
+        return Algorithm(statements.toList())
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/algorithms/AlgorithmSection.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/algorithms/AlgorithmSection.kt
@ -0,0 +1,80 @@
+package space.kscience.controls.constructor.dsl.core.algorithms
+
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+import space.kscience.controls.constructor.dsl.core.simulation.SimulationContext
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+
+/**
+ * Абстрактный класс для операторов в алгоритмической секции.
+ */
+public sealed class Statement {
+    public abstract suspend fun execute(context: SimulationContext)
+}
+
+public data class AssignmentStatement(
+    val variable: Variable,
+    val expression: Expression
+) : Statement() {
+    override suspend fun execute(context: SimulationContext) {
+        val value = expression.evaluate(context.getVariableValues())
+        context.updateVariable(variable.name, value)
+    }
+}
+
+public data class IfStatement(
+    val condition: Expression,
+    val trueBranch: Algorithm,
+    val falseBranch: Algorithm? = null
+) : Statement() {
+    override suspend fun execute(context: SimulationContext) {
+        val conditionValue = condition.evaluate(context.getVariableValues())
+        if (conditionValue != 0.0) {
+            trueBranch.execute(context)
+        } else {
+            falseBranch?.execute(context)
+        }
+    }
+}
+
+public data class ForStatement(
+    val variable: Variable,
+    val range: IntRange,
+    val body: Algorithm
+) : Statement() {
+    override suspend fun execute(context: SimulationContext) {
+        for (i in range) {
+            context.updateVariable(variable.name, i.toDouble())
+            body.execute(context)
+        }
+    }
+}
+
+public data class WhileStatement(
+    val condition: Expression,
+    val body: Algorithm
+) : Statement() {
+    override suspend fun execute(context: SimulationContext) {
+        while (condition.evaluate(context.getVariableValues()) != 0.0) {
+            body.execute(context)
+        }
+    }
+}
+
+public class Algorithm(private val statements: List<Statement>) {
+    /**
+     * Добавляет оператор в алгоритм.
+     */
+    public fun addStatement(statement: Statement) {
+        (statements as MutableList).add(statement)
+    }
+
+    /**
+     * Выполняет алгоритм в заданном контексте симуляции.
+     */
+    public suspend fun execute(context: SimulationContext) {
+        for (statement in statements) {
+            statement.execute(context)
+        }
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/components/Component.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/components/Component.kt
@ -0,0 +1,81 @@
+package space.kscience.controls.constructor.dsl.core.components
+
+import space.kscience.controls.constructor.dsl.core.Annotation
+import space.kscience.controls.constructor.dsl.core.equations.Equation
+import space.kscience.controls.constructor.dsl.core.variables.ParameterVariable
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Базовый класс для всех компонентов модели.
+ */
+public abstract class Component<V : Variable, P : ParameterVariable, C : Connector>(public val name: String) {
+    public val variables: MutableMap<String, V> = mutableMapOf()
+    public val parameters: MutableMap<String, P> = mutableMapOf()
+    public val equations: MutableList<Equation> = mutableListOf()
+    public val connectors: MutableMap<String, C> = mutableMapOf()
+    public val annotations: MutableList<Annotation> = mutableListOf()
+    public var isReplaceable: Boolean = false
+
+    /**
+     * Метод для инициализации переменных.
+     */
+    protected abstract fun initializeVariables()
+
+    /**
+     * Метод для определения уравнений компонента.
+     */
+    protected abstract fun defineEquations()
+
+    /**
+     * Метод для добавления переменной.
+     */
+    public fun addVariable(variable: V) {
+        if (variables.containsKey(variable.name)) {
+            throw IllegalArgumentException("Variable with name ${variable.name} already exists in component $name.")
+        }
+        variables[variable.name] = variable
+    }
+
+    /**
+     * Метод для добавления параметра.
+     */
+    public fun addParameter(parameter: P) {
+        if (parameters.containsKey(parameter.name)) {
+            throw IllegalArgumentException("Parameter with name ${parameter.name} already exists in component $name.")
+        }
+        parameters[parameter.name] = parameter
+    }
+
+    /**
+     * Метод для добавления уравнения.
+     */
+    public fun addEquation(equation: Equation) {
+        equations.add(equation)
+    }
+
+    /**
+     * Метод для добавления коннектора.
+     */
+    public fun addConnector(name: String, connector: C) {
+        if (connectors.containsKey(name)) {
+            throw IllegalArgumentException("Connector with name $name already exists in component $name.")
+        }
+        connectors[name] = connector
+    }
+
+    public fun annotate(annotation: Annotation) {
+        annotations.add(annotation)
+    }
+
+    /**
+     * Метод для модификации параметров компонента.
+     */
+    public fun modify(modifier: Component<V, P, C>.() -> Unit): Component<V, P, C> {
+        this.apply(modifier)
+        return this
+    }
+
+    public fun markAsReplaceable(isReplaceable: Boolean) {
+        this.isReplaceable = isReplaceable
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/components/Connection.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/components/Connection.kt
@ -0,0 +1,38 @@
+package space.kscience.controls.constructor.dsl.core.components
+
+import space.kscience.controls.constructor.dsl.core.equations.Equation
+import space.kscience.controls.constructor.dsl.core.expressions.VariableExpression
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Класс для представления соединения между двумя коннекторами.
+ */
+public class Connection<C : Connector>(
+    public val connector1: C,
+    public val connector2: C
+) {
+    init {
+        if (connector1.unit != connector2.unit) {
+            throw IllegalArgumentException("Cannot connect connectors with different units: ${connector1.unit} and ${connector2.unit}.")
+        }
+    }
+
+    /**
+     * Генерация уравнений для соединения.
+     */
+    public fun generateEquations(): List<Equation> {
+        val equations = mutableListOf<Equation>()
+        for ((varName, var1) in connector1.variables) {
+            val var2 = connector2.variables[varName]
+                ?: throw IllegalArgumentException("Variable $varName not found in connector ${connector2.name}.")
+
+            equations.add(
+                Equation(
+                    VariableExpression(var1),
+                    VariableExpression(var2)
+                )
+            )
+        }
+        return equations
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/components/Connector.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/components/Connector.kt
@ -0,0 +1,22 @@
+package space.kscience.controls.constructor.dsl.core.components
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Интерфейс для коннектора, позволяющего соединять компоненты.
+ */
+public interface Connector {
+    public val name: String
+    public val variables: Map<String, Variable>
+    public val unit: PhysicalUnit
+}
+
+/**
+ * Базовая реализация коннектора.
+ */
+public class BasicConnector(
+    override val name: String,
+    override val unit: PhysicalUnit,
+    override val variables: Map<String, Variable>
+) : Connector
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/components/Model.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/components/Model.kt
@ -0,0 +1,163 @@
+package space.kscience.controls.constructor.dsl.core.components
+
+import space.kscience.controls.constructor.dsl.core.*
+import space.kscience.controls.constructor.dsl.core.algorithms.*
+import space.kscience.controls.constructor.dsl.core.equations.Equation
+import space.kscience.controls.constructor.dsl.core.equations.ConditionalEquation
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+import space.kscience.controls.constructor.dsl.core.expressions.VariableExpression
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.variables.ParameterVariable
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+import space.kscience.controls.constructor.dsl.core.functions.Function
+import space.kscience.controls.constructor.dsl.core.functions.FunctionBuilder
+
+/**
+ * Класс для представления модели, содержащей компоненты и соединения.
+ */
+public class Model(public val name: String, init: Model.() -> Unit) {
+    public val components: MutableMap<String, Component<*, *, *>> = mutableMapOf<String, Component<*, *, *>>()
+    public val connections: MutableList<Connection<*>> = mutableListOf<Connection<*>>()
+    public val variables: MutableMap<String, Variable> = mutableMapOf<String, Variable>()
+    public val parameters: MutableMap<String, ParameterVariable> = mutableMapOf<String, ParameterVariable>()
+    public val equations: MutableList<Equation> = mutableListOf<Equation>()
+    public val initialValues: MutableMap<String, Double> = mutableMapOf<String, Double>()
+    public val initialEquations: MutableList<Equation> = mutableListOf<Equation>()
+    public val conditionalEquations: MutableList<ConditionalEquation> = mutableListOf<ConditionalEquation>()
+    public val algorithms: MutableList<Algorithm> = mutableListOf<Algorithm>()
+    public val functions: MutableMap<String, Function> = mutableMapOf<String, Function>()
+
+    init {
+        this.init()
+    }
+
+    /**
+     * Определение переменной.
+     */
+    public fun variable(name: String, unit: PhysicalUnit): VariableExpression {
+        val variable = Variable(name, unit)
+        variables[name] = variable
+        return VariableExpression(variable)
+    }
+
+    /**
+     * Определение параметра.
+     */
+    public fun parameter(name: String, unit: PhysicalUnit, value: Double): ParameterVariable {
+        val parameter = ParameterVariable(name, unit, value)
+        parameters[name] = parameter
+        return parameter
+    }
+
+    /**
+     * Добавление уравнения.
+     */
+    public fun equation(equationBuilder: () -> Equation) {
+        val equation = equationBuilder()
+        equations.add(equation)
+    }
+
+    /**
+     * Установка начальных значений.
+     */
+    public fun initialValues(init: MutableMap<String, Double>.() -> Unit) {
+        initialValues.apply(init)
+    }
+
+    /**
+     * Добавление инициализационного уравнения.
+     */
+    public fun initialEquation(equationBuilder: () -> Equation) {
+        val equation = equationBuilder()
+        initialEquations.add(equation)
+    }
+
+    /**
+     * Метод для добавления компонента.
+     */
+    public fun addComponent(component: Component<*, *, *>) {
+        if (components.containsKey(component.name)) {
+            throw IllegalArgumentException("Component with name ${component.name} already exists in model $name.")
+        }
+        components[component.name] = component
+    }
+
+    /**
+     * Метод для добавления соединения.
+     */
+    public fun addConnection(connection: Connection<*>) {
+        connections.add(connection)
+    }
+
+    /**
+     * Метод для генерации системы уравнений модели.
+     */
+    public fun generateEquationSystem(): EquationSystem {
+        val equationSystem = EquationSystem()
+
+        // Добавление уравнений модели
+        equationSystem.addEquations(equations)
+
+        // Добавление уравнений компонентов
+        for (component in components.values) {
+            equationSystem.addEquations(component.equations)
+        }
+
+        // Добавление уравнений соединений
+        for (connection in connections) {
+            equationSystem.addEquations(connection.generateEquations())
+        }
+
+        // Добавление условных уравнений
+        for (condEq in conditionalEquations) {
+            equationSystem.addEquation(condEq)
+        }
+
+        // Добавление инициализационных уравнений
+        equationSystem.addEquations(initialEquations)
+
+        return equationSystem
+    }
+
+    /**
+     * Метод для замены компонента.
+     */
+    public fun replaceComponent(name: String, newComponent: Component<*, *, *>) {
+        val oldComponent = components[name]
+        if (oldComponent != null && oldComponent.isReplaceable) {
+            components[name] = newComponent
+        } else {
+            throw IllegalArgumentException("Component $name is not replaceable or does not exist.")
+        }
+    }
+
+    /**
+     * Добавление условного уравнения.
+     */
+    public fun conditionalEquation(condition: Expression, trueEquation: Equation, falseEquation: Equation? = null) {
+        val condEq = ConditionalEquation(condition, trueEquation, falseEquation)
+        conditionalEquations.add(condEq)
+    }
+
+    /**
+     * Добавление алгоритма.
+     */
+    public fun algorithm(init: AlgorithmBuilder.() -> Unit) {
+        val builder = AlgorithmBuilder()
+        builder.init()
+        algorithms.add(builder.build())
+    }
+
+    /**
+     * Добавление пользовательской функции.
+     */
+    public fun function(name: String, init: FunctionBuilder.() -> Unit) {
+        if (functions.containsKey(name)) {
+            throw IllegalArgumentException("Function with name $name already exists in model $name.")
+        }
+        val builder = FunctionBuilder(name)
+        builder.init()
+        val function = builder.build()
+        functions[name] = function
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/components/Package.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/components/Package.kt
@ -0,0 +1,21 @@
+package space.kscience.controls.constructor.dsl.core.components
+
+/**
+ * Класс для представления пакета моделей.
+ */
+public class Package(public val name: String) {
+    public val models: MutableMap<String, Model> = mutableMapOf()
+    public val subPackages: MutableMap<String, Package> = mutableMapOf()
+
+    public fun addModel(model: Model) {
+        models[model.name] = model
+    }
+
+    public fun addPackage(pkg: Package) {
+        subPackages[pkg.name] = pkg
+    }
+
+    public fun getModel(name: String): Model? {
+        return models[name] ?: subPackages.values.mapNotNull { it.getModel(name) }.firstOrNull()
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/equations/ConditionalEquation.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/equations/ConditionalEquation.kt
@ -0,0 +1,12 @@
+package space.kscience.controls.constructor.dsl.core.equations
+
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+
+/**
+ * Класс для условного уравнения.
+ */
+public class ConditionalEquation(
+    public val condition: Expression,
+    public val trueEquation: Equation,
+    public val falseEquation: Equation? = null
+) : EquationBase()
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/equations/Equation.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/equations/Equation.kt
@ -0,0 +1,24 @@
+package space.kscience.controls.constructor.dsl.core.equations
+
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+
+/**
+ * Класс для представления уравнения.
+ */
+public class Equation(
+    public val leftExpression: Expression,
+    public val rightExpression: Expression
+) : EquationBase() {
+    init {
+        // Проверка совместимости единиц измерения
+        if (!leftExpression.unit.dimension.isCompatibleWith(rightExpression.unit.dimension)) {
+            throw IllegalArgumentException("Units of left and right expressions in the equation are not compatible.")
+        }
+    }
+
+    public fun evaluate(values: Map<String, Double>): Double {
+        val leftValue = leftExpression.evaluate(values)
+        val rightValue = rightExpression.evaluate(values)
+        return leftValue - rightValue
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/equations/EquationBase.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/equations/EquationBase.kt
@ -0,0 +1,6 @@
+package space.kscience.controls.constructor.dsl.core.equations
+
+/**
+ * Абстрактный базовый класс для уравнений.
+ */
+public sealed class EquationBase
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/equations/InitialEquation.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/equations/InitialEquation.kt
@ -0,0 +1,11 @@
+package space.kscience.controls.constructor.dsl.core.equations
+
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+
+/**
+ * Class representing an initial equation for setting initial conditions.
+ */
+public class InitialEquation(
+    public val leftExpression: Expression,
+    public val rightExpression: Expression
+) : EquationBase()
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/events/AssignAction.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/events/AssignAction.kt
@ -0,0 +1,18 @@
+package space.kscience.controls.constructor.dsl.core.events
+
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+import space.kscience.controls.constructor.dsl.core.simulation.SimulationContext
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Действие присваивания нового значения переменной.
+ */
+public data class AssignAction(
+    val variable: Variable,
+    val newValue: Expression
+) : EventAction() {
+    override suspend fun execute(context: SimulationContext) {
+        val value = newValue.evaluate(context.getVariableValues())
+        context.updateVariable(variable.name, value)
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/events/Event.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/events/Event.kt
@ -0,0 +1,30 @@
+package space.kscience.controls.constructor.dsl.core.events
+
+import space.kscience.controls.constructor.dsl.core.simulation.SimulationContext
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+
+/**
+ * Класс для представления события.
+ */
+public class Event(
+    public val condition: Expression,
+    public val actions: List<EventAction>
+) {
+    /**
+     * Метод для проверки, произошло ли событие.
+     */
+    public suspend fun checkEvent(context: SimulationContext): Boolean {
+        val values = context.getVariableValues()
+        val conditionValue = condition.evaluate(values)
+        return conditionValue > 0 // Событие происходит, когда условие положительно
+    }
+
+    /**
+     * Метод для выполнения действий при событии.
+     */
+    public suspend fun executeActions(context: SimulationContext) {
+        for (action in actions) {
+            action.execute(context)
+        }
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/events/EventAction.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/events/EventAction.kt
@ -0,0 +1,12 @@
+package space.kscience.controls.constructor.dsl.core.events
+
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+import space.kscience.controls.constructor.dsl.core.simulation.SimulationContext
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Абстрактный класс для действий при событии.
+ */
+public sealed class EventAction {
+    public abstract suspend fun execute(context: SimulationContext)
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/events/ReinitAction.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/events/ReinitAction.kt
@ -0,0 +1,18 @@
+package space.kscience.controls.constructor.dsl.core.events
+
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+import space.kscience.controls.constructor.dsl.core.simulation.SimulationContext
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Действие реинициализации переменной.
+ */
+public data class ReinitAction(
+    val variable: Variable,
+    val newValue: Expression
+) : EventAction() {
+    override suspend fun execute(context: SimulationContext) {
+        val value = newValue.evaluate(context.getVariableValues())
+        context.updateVariable(variable.name, value)
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expression/ExpressionOperators.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expression/ExpressionOperators.kt
@ -0,0 +1,91 @@
+package space.kscience.controls.constructor.dsl.core.expression
+
+import space.kscience.controls.constructor.dsl.core.variables.ArrayVariable
+import space.kscience.controls.constructor.dsl.core.equations.Equation
+import space.kscience.controls.constructor.dsl.core.expressions.ArrayBinaryExpression
+import space.kscience.controls.constructor.dsl.core.expressions.ArrayBinaryOperator
+import space.kscience.controls.constructor.dsl.core.expressions.ArrayScalarExpression
+import space.kscience.controls.constructor.dsl.core.expressions.ArrayScalarOperator
+import space.kscience.controls.constructor.dsl.core.expressions.BinaryExpression
+import space.kscience.controls.constructor.dsl.core.expressions.BinaryOperator
+import space.kscience.controls.constructor.dsl.core.expressions.ConstantExpression
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+import space.kscience.controls.constructor.dsl.core.expressions.FunctionCallExpression
+import space.kscience.controls.constructor.dsl.core.units.Units
+import space.kscience.controls.constructor.dsl.core.functions.Function
+
+// Операторные функции для скалярных выражений
+
+public operator fun Expression.plus(other: Expression): Expression {
+    return BinaryExpression(this, BinaryOperator.ADD, other)
+}
+
+public operator fun Expression.minus(other: Expression): Expression {
+    return BinaryExpression(this, BinaryOperator.SUBTRACT, other)
+}
+
+public operator fun Expression.times(other: Expression): Expression {
+    return BinaryExpression(this, BinaryOperator.MULTIPLY, other)
+}
+
+public operator fun Expression.div(other: Expression): Expression {
+    return BinaryExpression(this, BinaryOperator.DIVIDE, other)
+}
+
+public infix fun Expression.pow(exponent: Expression): Expression {
+    return FunctionCallExpression("pow", listOf(this, exponent))
+}
+
+public infix fun Expression.pow(exponent: Double): Expression {
+    return FunctionCallExpression("pow", listOf(this, ConstantExpression(exponent, Units.dimensionless)))
+}
+
+// Сравнительные операторы
+
+public infix fun Expression.eq(other: Expression): Equation {
+    return Equation(this, other)
+}
+
+public infix fun Expression.gt(other: Expression): Expression {
+    return BinaryExpression(this, BinaryOperator.GREATER_THAN, other)
+}
+
+public infix fun Expression.lt(other: Expression): Expression {
+    return BinaryExpression(this, BinaryOperator.LESS_THAN, other)
+}
+
+public infix fun Expression.ge(other: Expression): Expression {
+    return BinaryExpression(this, BinaryOperator.GREATER_OR_EQUAL, other)
+}
+
+public infix fun Expression.le(other: Expression): Expression {
+    return BinaryExpression(this, BinaryOperator.LESS_OR_EQUAL, other)
+}
+
+// Операторные функции для массивов
+
+public operator fun ArrayVariable.plus(other: ArrayVariable): Expression {
+    return ArrayBinaryExpression(this, ArrayBinaryOperator.ADD, other)
+}
+
+public operator fun ArrayVariable.minus(other: ArrayVariable): Expression {
+    return ArrayBinaryExpression(this, ArrayBinaryOperator.SUBTRACT, other)
+}
+
+public operator fun ArrayVariable.times(scalar: Expression): Expression {
+    return ArrayScalarExpression(this, ArrayScalarOperator.MULTIPLY, scalar)
+}
+
+public operator fun ArrayVariable.div(scalar: Expression): Expression {
+    return ArrayScalarExpression(this, ArrayScalarOperator.DIVIDE, scalar)
+}
+
+/**
+ * Функция для вызова пользовательской функции в выражении.
+ */
+public fun callFunction(function: Function, vararg args: Expression): FunctionCallExpression {
+    require(args.size == function.inputs.size) {
+        "Number of arguments does not match number of function inputs."
+    }
+    return FunctionCallExpression(function.name, args.toList())
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayBinaryExpression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayBinaryExpression.kt
@ -0,0 +1,37 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.variables.ArrayVariable
+
+/**
+ * Класс для представления бинарной операции между двумя массивами.
+ */
+public class ArrayBinaryExpression(
+    public val left: ArrayVariable,
+    public val operator: ArrayBinaryOperator,
+    public val right: ArrayVariable
+) : Expression() {
+
+    override val unit: PhysicalUnit = when (operator) {
+        ArrayBinaryOperator.ADD, ArrayBinaryOperator.SUBTRACT -> {
+            if (left.unit != right.unit) {
+                throw IllegalArgumentException("Units must be the same for array addition or subtraction.")
+            }
+            left.unit
+        }
+        ArrayBinaryOperator.MULTIPLY -> left.unit * right.unit
+        ArrayBinaryOperator.DIVIDE -> left.unit / right.unit
+    }
+
+    override fun evaluate(values: Map<String, Double>): Double {
+        throw UnsupportedOperationException("Cannot evaluate array expression to a scalar value.")
+    }
+
+    override fun checkDimensions() {
+        TODO()
+    }
+
+    override fun derivative(variable: VariableExpression): Expression {
+        throw UnsupportedOperationException("Derivative of array expression is not implemented.")
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayBinaryOperator.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayBinaryOperator.kt
@ -0,0 +1,11 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+/**
+ * Перечисление для бинарных операций над массивами.
+ */
+public enum class ArrayBinaryOperator {
+    ADD,
+    SUBTRACT,
+    MULTIPLY,
+    DIVIDE
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayExpression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayExpression.kt
@ -0,0 +1,3 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+public sealed class ArrayExpression : Expression()
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayScalarExpression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayScalarExpression.kt
@ -0,0 +1,34 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.variables.ArrayVariable
+
+/**
+ * Представляет операцию между массивом и скаляром.
+ */
+public class ArrayScalarExpression(
+    public val array: ArrayVariable,
+    public val operator: ArrayScalarOperator,
+    public val scalar: Expression
+) : Expression() {
+
+    override val unit: PhysicalUnit = when (operator) {
+        ArrayScalarOperator.MULTIPLY -> array.unit * scalar.unit
+        ArrayScalarOperator.DIVIDE -> array.unit / scalar.unit
+    }
+
+    override fun evaluate(values: Map<String, Double>): Double {
+        // Невозможно вычислить массивное выражение до скалярного значения
+        throw UnsupportedOperationException("Cannot evaluate array expression to a scalar value.")
+    }
+
+    override fun checkDimensions() {
+//        array.checkDimensions()
+        scalar.checkDimensions()
+        // Единицы измерения уже проверены в свойстве `unit`
+    }
+
+    override fun derivative(variable: VariableExpression): Expression {
+        throw UnsupportedOperationException("Derivative of array expression is not implemented.")
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayScalarOperator.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayScalarOperator.kt
@ -0,0 +1,9 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+/**
+ * Перечисление операторов между массивом и скаляром.
+ */
+public enum class ArrayScalarOperator {
+    MULTIPLY,
+    DIVIDE
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayVariableExpression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ArrayVariableExpression.kt
@ -0,0 +1,42 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+import space.kscience.controls.constructor.dsl.core.expressions.Expression
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.variables.ArrayVariable
+
+/**
+ * Представляет операцию между двумя массивами.
+ */
+public class ArrayVariableExpression(
+    public val left: ArrayVariable,
+    public val operator: ArrayBinaryOperator,
+    public val right: ArrayVariable
+) : Expression() {
+
+    override val unit: PhysicalUnit = when (operator) {
+        ArrayBinaryOperator.ADD, ArrayBinaryOperator.SUBTRACT -> {
+            if (left.unit != right.unit) {
+                throw IllegalArgumentException("Units must be the same for array addition or subtraction.")
+            }
+            left.unit
+        }
+        ArrayBinaryOperator.MULTIPLY -> left.unit * right.unit
+        ArrayBinaryOperator.DIVIDE -> left.unit / right.unit
+    }
+
+    override fun evaluate(values: Map<String, Double>): Double {
+        // Невозможно вычислить массивное выражение до скалярного значения
+        throw UnsupportedOperationException("Cannot evaluate array expression to a scalar value.")
+    }
+
+    override fun checkDimensions() {
+//        left.checkDimensions()
+//        right.checkDimensions()
+        // Единицы измерения уже проверены в свойстве `unit`
+    }
+
+    override fun derivative(variable: VariableExpression): Expression {
+        // Производная массива не реализована
+        throw UnsupportedOperationException("Derivative of array expression is not implemented.")
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/BinaryExpression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/BinaryExpression.kt
@ -0,0 +1,135 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.units.Units
+import kotlin.math.*
+
+/**
+ * Перечисление типов бинарных операций.
+ */
+public enum class BinaryOperator {
+    ADD,
+    SUBTRACT,
+    MULTIPLY,
+    DIVIDE,
+    POWER,
+    GREATER_THAN,
+    LESS_THAN,
+    GREATER_OR_EQUAL,
+    LESS_OR_EQUAL
+}
+
+/**
+ * Класс для представления бинарной операции.
+ */
+public class BinaryExpression(
+    public val left: Expression,
+    public val operator: BinaryOperator,
+    public val right: Expression
+) : Expression() {
+
+    override val unit: PhysicalUnit = when (operator) {
+        BinaryOperator.ADD, BinaryOperator.SUBTRACT -> {
+            if (left.unit != right.unit) {
+                throw IllegalArgumentException("Units of left and right expressions must be the same for addition or subtraction.")
+            }
+            left.unit
+        }
+        BinaryOperator.MULTIPLY -> left.unit * right.unit
+        BinaryOperator.DIVIDE -> left.unit / right.unit
+        BinaryOperator.POWER -> {
+            if (right is ConstantExpression) {
+                left.unit.pow(right.value)
+            } else {
+                throw IllegalArgumentException("Exponent must be a constant expression.")
+            }
+        }
+        BinaryOperator.GREATER_THAN, BinaryOperator.LESS_THAN,
+        BinaryOperator.GREATER_OR_EQUAL, BinaryOperator.LESS_OR_EQUAL -> {
+            Units.dimensionless
+        }
+    }
+
+    override fun evaluate(values: Map<String, Double>): Double {
+        val leftValue = left.evaluate(values)
+        val rightValue = right.evaluate(values)
+        return when (operator) {
+            BinaryOperator.ADD -> leftValue + rightValue
+            BinaryOperator.SUBTRACT -> leftValue - rightValue
+            BinaryOperator.MULTIPLY -> leftValue * rightValue
+            BinaryOperator.DIVIDE -> leftValue / rightValue
+            BinaryOperator.POWER -> leftValue.pow(rightValue)
+            BinaryOperator.GREATER_THAN -> if (leftValue > rightValue) 1.0 else 0.0
+            BinaryOperator.LESS_THAN -> if (leftValue < rightValue) 1.0 else 0.0
+            BinaryOperator.GREATER_OR_EQUAL -> if (leftValue >= rightValue) 1.0 else 0.0
+            BinaryOperator.LESS_OR_EQUAL -> if (leftValue <= rightValue) 1.0 else 0.0
+        }
+    }
+
+    override fun checkDimensions() {
+        left.checkDimensions()
+        right.checkDimensions()
+        when (operator) {
+            BinaryOperator.ADD, BinaryOperator.SUBTRACT -> {
+                if (left.unit != right.unit) {
+                    throw IllegalArgumentException("Units must be the same for addition or subtraction.")
+                }
+            }
+            BinaryOperator.MULTIPLY, BinaryOperator.DIVIDE -> {
+                // Единицы измерения уже вычислены в `unit`
+            }
+            BinaryOperator.POWER -> {
+                if (!right.unit.dimension.isDimensionless()) {
+                    throw IllegalArgumentException("Exponent must be dimensionless.")
+                }
+            }
+            BinaryOperator.GREATER_THAN, BinaryOperator.LESS_THAN,
+            BinaryOperator.GREATER_OR_EQUAL, BinaryOperator.LESS_OR_EQUAL -> {
+                if (left.unit != right.unit) {
+                    throw IllegalArgumentException("Units must be the same for comparison operations.")
+                }
+            }
+        }
+    }
+
+    override fun derivative(variable: VariableExpression): Expression {
+        return when (operator) {
+            BinaryOperator.ADD, BinaryOperator.SUBTRACT -> {
+                BinaryExpression(left.derivative(variable), operator, right.derivative(variable))
+            }
+            BinaryOperator.MULTIPLY -> {
+                // Правило произведения: (u*v)' = u'*v + u*v'
+                val leftDerivative = BinaryExpression(left.derivative(variable), BinaryOperator.MULTIPLY, right)
+                val rightDerivative = BinaryExpression(left, BinaryOperator.MULTIPLY, right.derivative(variable))
+                BinaryExpression(leftDerivative, BinaryOperator.ADD, rightDerivative)
+            }
+            BinaryOperator.DIVIDE -> {
+                // Правило частного: (u/v)' = (u'*v - u*v') / v^2
+                val numerator = BinaryExpression(
+                    BinaryExpression(left.derivative(variable), BinaryOperator.MULTIPLY, right),
+                    BinaryOperator.SUBTRACT,
+                    BinaryExpression(left, BinaryOperator.MULTIPLY, right.derivative(variable))
+                )
+                val denominator = BinaryExpression(right, BinaryOperator.POWER, ConstantExpression(2.0, Units.dimensionless))
+                BinaryExpression(numerator, BinaryOperator.DIVIDE, denominator)
+            }
+            BinaryOperator.POWER -> {
+                if (right is ConstantExpression) {
+                    // (u^n)' = n * u^(n-1) * u'
+                    val n = right.value
+                    val newExponent = ConstantExpression(n - 1.0, Units.dimensionless)
+                    val baseDerivative = left.derivative(variable)
+                    val powerExpression = BinaryExpression(left, BinaryOperator.POWER, newExponent)
+                    BinaryExpression(
+                        BinaryExpression(ConstantExpression(n, Units.dimensionless), BinaryOperator.MULTIPLY, powerExpression),
+                        BinaryOperator.MULTIPLY,
+                        baseDerivative
+                    )
+                } else {
+                    throw UnsupportedOperationException("Derivative of expression with variable exponent is not supported.")
+                }
+            }
+            else -> throw UnsupportedOperationException("Derivative not implemented for operator $operator.")
+        }
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ConstantExpression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/ConstantExpression.kt
@ -0,0 +1,20 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.units.Units
+
+/**
+ * Класс для представления константного значения.
+ */
+public class ConstantExpression(public val value: Double, override val unit: PhysicalUnit) : Expression() {
+    override fun evaluate(values: Map<String, Double>): Double {
+        return value
+    }
+    override fun checkDimensions() {
+        // Константа имеет единицу измерения, дополнительных проверок не требуется
+    }
+
+    override fun derivative(variable: VariableExpression): Expression {
+        return ConstantExpression(0.0, Units.dimensionless)
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/DerivativeExpression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/DerivativeExpression.kt
@ -0,0 +1,30 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.units.Units
+
+/**
+ * Класс для представления производной переменной по времени.
+ */
+public class DerivativeExpression(
+    public val variable: VariableExpression,
+    public val order: Int = 1 // Порядок производной (по умолчанию 1)
+) : Expression() {
+
+    override val unit: PhysicalUnit = variable.unit / Units.second.pow(order.toDouble())
+
+    override fun evaluate(values: Map<String, Double>): Double {
+        // вычисление производной невозможно в этом контексте
+        throw UnsupportedOperationException("Cannot evaluate derivative directly.")
+    }
+
+    override fun checkDimensions() {
+        variable.checkDimensions()
+        // Единица измерения уже рассчитана
+    }
+
+    override fun derivative(variable: VariableExpression): Expression {
+        // Производная от производной - это производная более высокого порядка
+        return DerivativeExpression(this.variable, this.order + 1)
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/Expression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/Expression.kt
@ -0,0 +1,34 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+
+/**
+ * Абстрактный класс для представления математических выражений.
+ * Каждое выражение связано с единицей измерения.
+ */
+public abstract class Expression {
+    public abstract val unit: PhysicalUnit
+
+    /**
+     * Метод для вычисления численного значения выражения.
+     * Параметр values содержит значения переменных.
+     */
+    public abstract fun evaluate(values: Map<String, Double>): Double
+
+    /**
+     * Проверка размерности выражения.
+     */
+    public abstract fun checkDimensions()
+
+    /**
+     * Упрощение выражения.
+     */
+    public open fun simplify(): Expression = this
+
+    /**
+     * Производная выражения по заданной переменной.
+     */
+    public open fun derivative(variable: VariableExpression): Expression {
+        throw UnsupportedOperationException("Derivative not implemented for this expression type.")
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/FunctionCallExpression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/FunctionCallExpression.kt
@ -0,0 +1,91 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+import space.kscience.controls.constructor.dsl.core.units.Units
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import kotlin.math.*
+
+/**
+ * Класс для представления вызова математической функции.
+ */
+public class FunctionCallExpression(
+    public val functionName: String,
+    public val arguments: List<Expression>
+) : Expression() {
+
+    override val unit: PhysicalUnit = determineUnit()
+
+    private fun determineUnit(): PhysicalUnit {
+        return when (functionName) {
+            "sin", "cos", "tan", "asin", "acos", "atan",
+            "sinh", "cosh", "tanh", "asinh", "acosh", "atanh",
+            "exp", "log", "log10", "signum" -> Units.dimensionless
+            "sqrt", "cbrt", "abs" -> arguments[0].unit
+            "pow", "max", "min" -> arguments[0].unit
+            else -> throw IllegalArgumentException("Unknown function: $functionName")
+        }
+    }
+
+    override fun evaluate(values: Map<String, Double>): Double {
+        val argValues = arguments.map { it.evaluate(values) }
+        return when (functionName) {
+            "sin" -> sin(argValues[0])
+            "cos" -> cos(argValues[0])
+            "tan" -> tan(argValues[0])
+            "asin" -> asin(argValues[0])
+            "acos" -> acos(argValues[0])
+            "atan" -> atan(argValues[0])
+            "sinh" -> sinh(argValues[0])
+            "cosh" -> cosh(argValues[0])
+            "tanh" -> tanh(argValues[0])
+            "asinh" -> asinh(argValues[0])
+            "acosh" -> acosh(argValues[0])
+            "atanh" -> atanh(argValues[0])
+            "exp" -> exp(argValues[0])
+            "log" -> ln(argValues[0])
+            "log10" -> log10(argValues[0])
+            "sqrt" -> sqrt(argValues[0])
+            "cbrt" -> cbrt(argValues[0])
+            "abs" -> abs(argValues[0])
+            "signum" -> sign(argValues[0])
+            "pow" -> argValues[0].pow(argValues[1])
+            "max" -> max(argValues[0], argValues[1])
+            "min" -> min(argValues[0], argValues[1])
+            else -> throw IllegalArgumentException("Unknown function: $functionName")
+        }
+    }
+
+    override fun checkDimensions() {
+        when (functionName) {
+            "sin", "cos", "tan", "asin", "acos", "atan",
+            "sinh", "cosh", "tanh", "asinh", "acosh", "atanh",
+            "exp", "log", "log10", "signum" -> {
+                val argUnit = arguments[0].unit
+                if (!argUnit.dimension.isDimensionless()) {
+                    throw IllegalArgumentException("Argument of $functionName must be dimensionless.")
+                }
+            }
+            "sqrt", "cbrt", "abs" -> {
+                // Единица измерения сохраняется, дополнительных проверок не требуется
+            }
+            "pow" -> {
+                val exponentUnit = arguments[1].unit
+                if (!exponentUnit.dimension.isDimensionless()) {
+                    throw IllegalArgumentException("Exponent in $functionName must be dimensionless.")
+                }
+            }
+            "max", "min" -> {
+                if (arguments[0].unit != arguments[1].unit) {
+                    throw IllegalArgumentException("Arguments of $functionName must have the same units.")
+                }
+            }
+            else -> throw IllegalArgumentException("Unknown function: $functionName")
+        }
+        // Проверяем размерности аргументов
+        arguments.forEach { it.checkDimensions() }
+    }
+
+    override fun derivative(variable: VariableExpression): Expression {
+        // Реализация производной для функций
+        throw UnsupportedOperationException("Derivative for function $functionName is not implemented.")
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/PartialDerivativeExpression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/PartialDerivativeExpression.kt
@ -0,0 +1,31 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+
+/**
+ * Представляет частную производную переменной по другой переменной.
+ */
+public class PartialDerivativeExpression(
+    public val variable: VariableExpression,
+    public val respectTo: VariableExpression,
+    public val order: Int = 1
+) : Expression() {
+
+    override val unit: PhysicalUnit = variable.unit / respectTo.unit.pow(order.toDouble())
+
+    override fun evaluate(values: Map<String, Double>): Double {
+        // Невозможно вычислить частную производную без дополнительного контекста
+        throw UnsupportedOperationException("Cannot evaluate partial derivative directly.")
+    }
+
+    override fun checkDimensions() {
+        variable.checkDimensions()
+        respectTo.checkDimensions()
+        // Единицы измерения уже рассчитаны
+    }
+
+    override fun derivative(variable: VariableExpression): Expression {
+        // Производная частной производной не реализована
+        throw UnsupportedOperationException("Derivative of partial derivative is not implemented.")
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/VariableExpression.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/expressions/VariableExpression.kt
@ -0,0 +1,32 @@
+package space.kscience.controls.constructor.dsl.core.expressions
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.units.Units
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Класс для представления переменной в выражении.
+ */
+public class VariableExpression(public val variable: Variable) : Expression() {
+    override val unit: PhysicalUnit = variable.unit
+
+    override fun evaluate(values: Map<String, Double>): Double {
+        return values[variable.name] ?: throw IllegalArgumentException("Variable ${variable.name} is not defined.")
+    }
+
+    override fun checkDimensions() {
+        // Переменная уже имеет единицу измерения, дополнительных проверок не требуется
+    }
+
+    override fun derivative(variable: VariableExpression): Expression {
+        return if (this.variable == variable.variable) {
+            ConstantExpression(1.0, Units.dimensionless)
+        } else {
+            ConstantExpression(0.0, Units.dimensionless)
+        }
+    }
+
+    public fun partialDerivative(respectTo: VariableExpression, order: Int = 1): PartialDerivativeExpression {
+        return PartialDerivativeExpression(this, respectTo, order)
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/functions/Function.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/functions/Function.kt
@ -0,0 +1,14 @@
+package space.kscience.controls.constructor.dsl.core.functions
+
+import space.kscience.controls.constructor.dsl.core.algorithms.Algorithm
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Класс для представления пользовательской функции.
+ */
+public data class Function(
+    val name: String,
+    val inputs: List<Variable>,
+    val outputs: List<Variable>,
+    val algorithm: Algorithm
+)
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/functions/FunctionBuilder.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/functions/FunctionBuilder.kt
@ -0,0 +1,50 @@
+package space.kscience.controls.constructor.dsl.core.functions
+
+import space.kscience.controls.constructor.dsl.core.algorithms.AlgorithmBuilder
+import space.kscience.controls.constructor.dsl.core.algorithms.Algorithm
+import space.kscience.controls.constructor.dsl.core.components.Model
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.variables.Causality
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Класс для построения пользовательской функции.
+ */
+public class FunctionBuilder(private val name: String) {
+    public val inputs: MutableList<Variable> = mutableListOf<Variable>()
+    public val outputs: MutableList<Variable> = mutableListOf<Variable>()
+    private val algorithmBuilder = AlgorithmBuilder()
+
+    /**
+     * Определение входного параметра функции.
+     */
+    public fun input(name: String, unit: PhysicalUnit): Variable {
+        val variable = Variable(name, unit, causality = Causality.INPUT)
+        inputs.add(variable)
+        return variable
+    }
+
+    /**
+     * Определение выходного параметра функции.
+     */
+    public fun output(name: String, unit: PhysicalUnit): Variable {
+        val variable = Variable(name, unit, causality = Causality.OUTPUT)
+        outputs.add(variable)
+        return variable
+    }
+
+    /**
+     * Определение алгоритмического тела функции.
+     */
+    public fun algorithm(init: AlgorithmBuilder.() -> Unit) {
+        algorithmBuilder.init()
+    }
+
+    /**
+     * Построение функции.
+     */
+    public fun build(): Function {
+        val algorithm = algorithmBuilder.build()
+        return Function(name, inputs, outputs, algorithm)
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/simulation/NumericSolver.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/simulation/NumericSolver.kt
@ -0,0 +1,37 @@
+package space.kscience.controls.constructor.dsl.core.simulation
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.StateFlow
+import space.kscience.controls.constructor.dsl.core.EquationSystem
+import space.kscience.controls.constructor.dsl.core.events.Event
+
+public interface NumericSolver {
+    /**
+     * Инициализирует решатель.
+     */
+    public suspend fun initialize(
+        equationSystem: EquationSystem,
+        context: SimulationContext
+    )
+
+    /**
+     * Выполняет один шаг симуляции.
+     */
+    public suspend fun step(context: SimulationContext, timeStep: Double): Boolean
+
+    /**
+     * Запускает симуляцию.
+     */
+    public suspend fun solve(
+        equationSystem: EquationSystem,
+        context: SimulationContext,
+        timeStart: Double,
+        timeEnd: Double,
+        timeStep: Double
+    ): SimulationResult
+}
+
+public data class SimulationResult(
+    val timePoints: List<Double>,
+    val variableValues: Map<String, List<Double>>
+)
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/simulation/SimulationContext.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/simulation/SimulationContext.kt
@ -0,0 +1,93 @@
+package space.kscience.controls.constructor.dsl.core.simulation
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.launch
+import space.kscience.controls.constructor.dsl.core.events.Event
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+/**
+ * Класс для хранения состояния симуляции.
+ */
+public class SimulationContext(
+    private val scope: CoroutineScope
+) {
+    public var currentTime: Double = 0.0
+    private val _variableValues: MutableMap<String, MutableStateFlow<Double>> = mutableMapOf()
+
+    // Канал для событий
+    private val eventChannel = Channel<Event>()
+
+    // Список событий
+    public val events: MutableList<Event> = mutableListOf()
+
+    /**
+     * Регистрирует переменную в контексте симуляции.
+     */
+    public fun registerVariable(variable: Variable) {
+        _variableValues[variable.name] = MutableStateFlow(variable.value)
+    }
+
+    /**
+     * Обновляет значение переменной.
+     */
+    public suspend fun updateVariable(name: String, value: Double) {
+        _variableValues[name]?.emit(value)
+            ?: throw IllegalArgumentException("Variable $name is not defined in the simulation context.")
+    }
+
+    /**
+     * Получает текущее значение переменной.
+     */
+    public fun getCurrentVariableValue(name: String): Double {
+        return _variableValues[name]?.value
+            ?: throw IllegalArgumentException("Variable $name is not defined in the simulation context.")
+    }
+
+    /**
+     * Возвращает текущие значения всех переменных.
+     */
+    public fun getVariableValues(): Map<String, Double> {
+        return _variableValues.mapValues { it.value.value }
+    }
+
+    /**
+     * Отправляет событие на обработку.
+     */
+    public suspend fun sendEvent(event: Event) {
+        eventChannel.send(event)
+    }
+
+    /**
+     * Запускает обработку событий.
+     */
+    public fun startEventHandling() {
+        scope.launch {
+            for (event in eventChannel) {
+                if (event.checkEvent(this@SimulationContext)) {
+                    event.executeActions(this@SimulationContext)
+                }
+            }
+        }
+    }
+
+    /**
+     * Обрабатывает события из списка events.
+     */
+    public suspend fun handleEvents() {
+        for (event in events) {
+            if (event.checkEvent(this)) {
+                event.executeActions(this)
+            }
+        }
+    }
+
+    /**
+     * Увеличивает время симуляции.
+     */
+    public suspend fun advanceTime(deltaTime: Double) {
+        currentTime += deltaTime
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/units/Dimension.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/units/Dimension.kt
@ -0,0 +1,78 @@
+package space.kscience.controls.constructor.dsl.core.units
+
+import kotlin.math.abs
+
+/**
+ * Класс для представления размерности физической величины.
+ */
+public data class Dimension(
+    val length: Double = 0.0,
+    val mass: Double = 0.0,
+    val time: Double = 0.0,
+    val electricCurrent: Double = 0.0,
+    val temperature: Double = 0.0,
+    val amountOfSubstance: Double = 0.0,
+    val luminousIntensity: Double = 0.0
+) {
+    public operator fun plus(other: Dimension): Dimension {
+        return Dimension(
+            length + other.length,
+            mass + other.mass,
+            time + other.time,
+            electricCurrent + other.electricCurrent,
+            temperature + other.temperature,
+            amountOfSubstance + other.amountOfSubstance,
+            luminousIntensity + other.luminousIntensity
+        )
+    }
+
+    public operator fun minus(other: Dimension): Dimension {
+        return Dimension(
+            length - other.length,
+            mass - other.mass,
+            time - other.time,
+            electricCurrent - other.electricCurrent,
+            temperature - other.temperature,
+            amountOfSubstance - other.amountOfSubstance,
+            luminousIntensity - other.luminousIntensity
+        )
+    }
+
+    public operator fun times(factor: Double): Dimension {
+        return Dimension(
+            length * factor,
+            mass * factor,
+            time * factor,
+            electricCurrent * factor,
+            temperature * factor,
+            amountOfSubstance * factor,
+            luminousIntensity * factor
+        )
+    }
+
+    /**
+     * Проверяет, является ли размерность безразмерной.
+     */
+    public fun isDimensionless(epsilon: Double = 1e-10): Boolean {
+        return abs(length) < epsilon &&
+                abs(mass) < epsilon &&
+                abs(time) < epsilon &&
+                abs(electricCurrent) < epsilon &&
+                abs(temperature) < epsilon &&
+                abs(amountOfSubstance) < epsilon &&
+                abs(luminousIntensity) < epsilon
+    }
+
+    /**
+     * Проверяет совместимость размерностей.
+     */
+    public fun isCompatibleWith(other: Dimension, epsilon: Double = 1e-10): Boolean {
+        return abs(length - other.length) < epsilon &&
+                abs(mass - other.mass) < epsilon &&
+                abs(time - other.time) < epsilon &&
+                abs(electricCurrent - other.electricCurrent) < epsilon &&
+                abs(temperature - other.temperature) < epsilon &&
+                abs(amountOfSubstance - other.amountOfSubstance) < epsilon &&
+                abs(luminousIntensity - other.luminousIntensity) < epsilon
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/units/PhysicalUnit.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/units/PhysicalUnit.kt
@ -0,0 +1,51 @@
+package space.kscience.controls.constructor.dsl.core.units
+
+import kotlin.math.pow
+
+/**
+ * Класс для представления физической единицы измерения.
+ */
+public data class PhysicalUnit(
+    val name: String,
+    val symbol: String,
+    val conversionFactorToSI: Double,
+    val dimension: Dimension
+) {
+    public operator fun times(other: PhysicalUnit): PhysicalUnit {
+        return PhysicalUnit(
+            name = "$name·${other.name}",
+            symbol = "$symbol·${other.symbol}",
+            conversionFactorToSI = this.conversionFactorToSI * other.conversionFactorToSI,
+            dimension = this.dimension + other.dimension
+        )
+    }
+
+    public operator fun div(other: PhysicalUnit): PhysicalUnit {
+        return PhysicalUnit(
+            name = "$name/${other.name}",
+            symbol = "$symbol/${other.symbol}",
+            conversionFactorToSI = this.conversionFactorToSI / other.conversionFactorToSI,
+            dimension = this.dimension - other.dimension
+        )
+    }
+
+    public fun pow(exponent: Double): PhysicalUnit {
+        return PhysicalUnit(
+            name = "$name^$exponent",
+            symbol = "${symbol}^$exponent",
+            conversionFactorToSI = this.conversionFactorToSI.pow(exponent),
+            dimension = this.dimension * exponent
+        )
+    }
+
+    /**
+     * Преобразует значение из текущей единицы в целевую единицу.
+     */
+    public fun convertValueTo(valueInThisUnit: Double, targetUnit: PhysicalUnit): Double {
+        require(this.dimension.isCompatibleWith(targetUnit.dimension)) {
+            "Units are not compatible: $this and $targetUnit"
+        }
+        val valueInSI = valueInThisUnit * this.conversionFactorToSI
+        return valueInSI / targetUnit.conversionFactorToSI
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/units/Units.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/units/Units.kt
@ -0,0 +1,89 @@
+package space.kscience.controls.constructor.dsl.core.units
+
+import kotlin.math.*
+
+public object Units {
+    private val unitsRegistry = mutableMapOf<String, PhysicalUnit>()
+
+    // Основные единицы СИ
+    public val meter: PhysicalUnit = PhysicalUnit("meter", "m", 1.0, Dimension(length = 1.0))
+    public val kilogram: PhysicalUnit = PhysicalUnit("kilogram", "kg", 1.0, Dimension(mass = 1.0))
+    public val second: PhysicalUnit = PhysicalUnit("second", "s", 1.0, Dimension(time = 1.0))
+    public val ampere: PhysicalUnit = PhysicalUnit("ampere", "A", 1.0, Dimension(electricCurrent = 1.0))
+    public val kelvin: PhysicalUnit = PhysicalUnit("kelvin", "K", 1.0, Dimension(temperature = 1.0))
+    public val mole: PhysicalUnit = PhysicalUnit("mole", "mol", 1.0, Dimension(amountOfSubstance = 1.0))
+    public val candela: PhysicalUnit = PhysicalUnit("candela", "cd", 1.0, Dimension(luminousIntensity = 1.0))
+    public val radian: PhysicalUnit = PhysicalUnit("radian", "rad", 1.0, Dimension())
+    public val hertz: PhysicalUnit = PhysicalUnit("hertz", "Hz", 1.0, Dimension(time = -1.0))
+
+    public val dimensionless: PhysicalUnit = PhysicalUnit("dimensionless", "", 1.0, Dimension())
+
+    init {
+        // Регистрируем основные единицы
+        registerUnit(meter)
+        registerUnit(kilogram)
+        registerUnit(second)
+        registerUnit(ampere)
+        registerUnit(kelvin)
+        registerUnit(mole)
+        registerUnit(candela)
+        registerUnit(radian)
+        registerUnit(hertz)
+    }
+
+    /**
+     * Регистрирует единицу измерения в реестре.
+     */
+    public fun registerUnit(unit: PhysicalUnit) {
+        unitsRegistry[unit.name] = unit
+    }
+
+    /**
+     * Получает единицу измерения по имени.
+     */
+    public fun getUnit(name: String): PhysicalUnit? {
+        return unitsRegistry[name]
+    }
+
+    /**
+     * Список префиксов СИ.
+     */
+    public enum class Prefix(public val prefixName: String, public val symbol: String, public val factor: Double) {
+        YOTTA("yotta", "Y", 1e24),
+        ZETTA("zetta", "Z", 1e21),
+        EXA("exa", "E", 1e18),
+        PETA("peta", "P", 1e15),
+        TERA("tera", "T", 1e12),
+        GIGA("giga", "G", 1e9),
+        MEGA("mega", "M", 1e6),
+        KILO("kilo", "k", 1e3),
+        HECTO("hecto", "h", 1e2),
+        DECA("deca", "da", 1e1),
+        DECI("deci", "d", 1e-1),
+        CENTI("centi", "c", 1e-2),
+        MILLI("milli", "m", 1e-3),
+        MICRO("micro", "μ", 1e-6),
+        NANO("nano", "n", 1e-9),
+        PICO("pico", "p", 1e-12),
+        FEMTO("femto", "f", 1e-15),
+        ATTO("atto", "a", 1e-18),
+        ZEPTO("zepto", "z", 1e-21),
+        YOCTO("yocto", "y", 1e-24)
+    }
+
+    /**
+     * Создает новую единицу с заданным префиксом.
+     */
+    public fun withPrefix(prefix: Prefix, unit: PhysicalUnit): PhysicalUnit {
+        val newName = "${prefix.prefixName}${unit.name}"
+        val newSymbol = "${prefix.symbol}${unit.symbol}"
+        val newConversionFactor = unit.conversionFactorToSI * prefix.factor
+        val newUnit = PhysicalUnit(newName, newSymbol, newConversionFactor, unit.dimension)
+        registerUnit(newUnit)
+        return newUnit
+    }
+
+    public val kilometer: PhysicalUnit = withPrefix(Prefix.KILO, meter)
+    public val millimeter: PhysicalUnit = withPrefix(Prefix.MILLI, meter)
+    public val microsecond: PhysicalUnit = withPrefix(Prefix.MICRO, second)
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/AbstractVariable.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/AbstractVariable.kt
@ -0,0 +1,13 @@
+package space.kscience.controls.constructor.dsl.core.variables
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+
+/**
+ * Абстрактный класс для переменных.
+ */
+public abstract class AbstractVariable(
+    public val name: String,
+    public val unit: PhysicalUnit,
+    public val variability: Variability,
+    public val causality: Causality
+)
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/ArrayVariable.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/ArrayVariable.kt
@ -0,0 +1,28 @@
+package space.kscience.controls.constructor.dsl.core.variables
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import org.jetbrains.kotlinx.multik.ndarray.data.D2
+import org.jetbrains.kotlinx.multik.ndarray.data.NDArray
+import org.jetbrains.kotlinx.multik.ndarray.data.set
+import org.jetbrains.kotlinx.multik.ndarray.operations.plus
+
+/**
+ * Класс для представления переменной-массива.
+ * Использует Multik для работы с многомерными массивами.
+ */
+public class ArrayVariable(
+    name: String,
+    unit: PhysicalUnit,
+    public val array: NDArray<Double, D2>,
+    causality: Causality = Causality.INTERNAL
+) : AbstractVariable(name, unit, Variability.CONTINUOUS, causality) {
+
+    public fun add(other: ArrayVariable): ArrayVariable {
+        require(this.array.shape contentEquals other.array.shape) {
+            "Array shapes do not match."
+        }
+        val resultArray = this.array + other.array
+        return ArrayVariable("$name + ${other.name}", unit, resultArray, causality)
+    }
+
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/Causality.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/Causality.kt
@ -0,0 +1,10 @@
+package space.kscience.controls.constructor.dsl.core.variables
+
+/**
+ * Перечисление каузальности переменной.
+ */
+public enum class Causality {
+    INPUT,
+    OUTPUT,
+    INTERNAL
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/ConstantVariable.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/ConstantVariable.kt
@ -0,0 +1,12 @@
+package space.kscience.controls.constructor.dsl.core.variables
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+
+/**
+ * Класс для представления константы.
+ */
+public class ConstantVariable(
+    name: String,
+    unit: PhysicalUnit,
+    public val value: Double
+) : AbstractVariable(name, unit, Variability.CONSTANT, Causality.INTERNAL)
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/ContinuousVariable.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/ContinuousVariable.kt
@ -0,0 +1,22 @@
+package space.kscience.controls.constructor.dsl.core.variables
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+
+public class ContinuousVariable(
+    name: String,
+    unit: PhysicalUnit,
+    public var value: Double = 0.0,
+    public val min: Double? = null,
+    public val max: Double? = null,
+    causality: Causality = Causality.INTERNAL
+) : AbstractVariable(name, unit, Variability.CONTINUOUS, causality) {
+    init {
+        // Проверка допустимого диапазона
+        if (min != null && value < min) {
+            throw IllegalArgumentException("Value of $name is less than minimum allowed value.")
+        }
+        if (max != null && value > max) {
+            throw IllegalArgumentException("Value of $name is greater than maximum allowed value.")
+        }
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/DiscreteVariable.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/DiscreteVariable.kt
@ -0,0 +1,13 @@
+package space.kscience.controls.constructor.dsl.core.variables
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+
+/**
+ * Класс для представления дискретной переменной.
+ */
+public class DiscreteVariable(
+    name: String,
+    unit: PhysicalUnit,
+    public var value: Double = 0.0,
+    causality: Causality = Causality.INTERNAL
+) : AbstractVariable(name, unit, Variability.DISCRETE, causality)
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/ParameterVariable.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/ParameterVariable.kt
@ -0,0 +1,25 @@
+package space.kscience.controls.constructor.dsl.core.variables
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+
+/**
+ * Класс для представления параметра (неизменяемой величины).
+ */
+public open class ParameterVariable(
+    name: String,
+    unit: PhysicalUnit,
+    public val value: Double,
+    public val min: Double? = null,
+    public val max: Double? = null,
+    causality: Causality = Causality.INTERNAL
+) : AbstractVariable(name, unit, Variability.PARAMETER, causality) {
+    init {
+        // Проверка допустимого диапазона
+        if (min != null && value < min) {
+            throw IllegalArgumentException("Value of parameter $name is less than minimum allowed value.")
+        }
+        if (max != null && value > max) {
+            throw IllegalArgumentException("Value of parameter $name is greater than maximum allowed value.")
+        }
+    }
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/Variability.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/Variability.kt
@ -0,0 +1,11 @@
+package space.kscience.controls.constructor.dsl.core.variables
+
+/**
+ * Перечисление типов изменчивости переменной.
+ */
+public enum class Variability {
+    CONSTANT,
+    PARAMETER,
+    DISCRETE,
+    CONTINUOUS
+}
--- a/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/Variable.kt
+++ b/controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/dsl/core/variables/Variable.kt
@ -0,0 +1,28 @@
+package space.kscience.controls.constructor.dsl.core.variables
+
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+
+/**
+ * Класс для представления переменной.
+ */
+public open class Variable(
+    public val name: String,
+    public val unit: PhysicalUnit,
+    public open var value: Double = 0.0,
+    public val min: Double? = null,
+    public val max: Double? = null,
+    public var variability: Variability = Variability.CONTINUOUS,
+    public var causality: Causality = Causality.INTERNAL
+) {
+    init {
+        // Проверка, что значение находится в допустимом диапазоне
+        if (min != null && value < min) {
+            throw IllegalArgumentException("Value of $name is less than minimum allowed value.")
+        }
+        if (max != null && value > max) {
+            throw IllegalArgumentException("Value of $name is greater than maximum allowed value.")
+        }
+    }
+
+    public open fun checkDimensions() {}
+}
--- a/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/EquationsTest.kt
+++ b/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/EquationsTest.kt
@ -0,0 +1,89 @@
+package space.kscience.controls.constructor
+
+import space.kscience.controls.constructor.dsl.core.EquationSystem
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+import kotlin.test.assertTrue
+import space.kscience.controls.constructor.dsl.core.equations.*
+import space.kscience.controls.constructor.dsl.core.expressions.*
+import space.kscience.controls.constructor.dsl.core.units.Units
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+class EquationsTest {
+
+    @Test
+    fun testCreatingEquations() {
+        val xVar = Variable("x", Units.meter)
+        val xExpr = VariableExpression(xVar)
+        val yVar = Variable("y", Units.meter)
+        val yExpr = VariableExpression(yVar)
+        val constExpr = ConstantExpression(5.0, Units.meter)
+
+        // Regular equation: x = y + 5
+        val equation = Equation(xExpr, BinaryExpression(yExpr, BinaryOperator.ADD, constExpr))
+        assertEquals(xExpr, equation.leftExpression)
+        assertEquals(BinaryExpression(yExpr, BinaryOperator.ADD, constExpr), equation.rightExpression)
+
+        // Conditional equation: if x > 0 then y = x else y = -x
+        val condition = BinaryExpression(xExpr, BinaryOperator.GREATER_THAN, ConstantExpression(0.0, Units.meter))
+        val trueEquation = Equation(yExpr, xExpr)
+        val falseEquation = Equation(yExpr, BinaryExpression(ConstantExpression(0.0, Units.meter), BinaryOperator.SUBTRACT, xExpr))
+        val conditionalEquation = ConditionalEquation(condition, trueEquation, falseEquation)
+        assertEquals(condition, conditionalEquation.condition)
+        assertEquals(trueEquation, conditionalEquation.trueEquation)
+        assertEquals(falseEquation, conditionalEquation.falseEquation)
+
+        // Initial equation: x(0) = 0
+        val initialEquation = InitialEquation(xExpr, ConstantExpression(0.0, Units.meter))
+        assertEquals(xExpr, initialEquation.leftExpression)
+        assertEquals(ConstantExpression(0.0, Units.meter), initialEquation.rightExpression)
+    }
+
+    @Test
+    fun testUnitCompatibilityInEquations() {
+        val lengthVar = Variable("length", Units.meter)
+        val lengthExpr = VariableExpression(lengthVar)
+        val timeVar = Variable("time", Units.second)
+        val timeExpr = VariableExpression(timeVar)
+
+        // Correct equation: length = length + length
+        val validEquation = Equation(lengthExpr, BinaryExpression(lengthExpr, BinaryOperator.ADD, ConstantExpression(5.0, Units.meter)))
+        assertFailsWith<Exception> {
+            validEquation
+        }
+
+        // Incorrect equation: length = time
+        val exception = assertFailsWith<IllegalArgumentException> {
+            Equation(lengthExpr, timeExpr)
+        }
+        assertEquals("Units of left and right expressions in the equation are not compatible.", exception.message)
+    }
+
+    @Test
+    fun testEquationSystem() {
+        val xVar = Variable("x", Units.meter)
+        val xExpr = VariableExpression(xVar)
+        val vVar = Variable("v", Units.meter / Units.second)
+        val vExpr = VariableExpression(vVar)
+        val aVar = Variable("a", Units.meter / Units.second.pow(2.0))
+        val aExpr = VariableExpression(aVar)
+
+        // Differential equation: der(x) = v
+        val derX = DerivativeExpression(xExpr)
+        val eq1 = Equation(derX, vExpr)
+
+        // Algebraic equation: v = a * t
+        val tVar = Variable("t", Units.second)
+        val tExpr = VariableExpression(tVar)
+        val eq2 = Equation(vExpr, BinaryExpression(aExpr, BinaryOperator.MULTIPLY, tExpr))
+
+        val equationSystem = EquationSystem()
+        equationSystem.addEquation(eq1)
+        equationSystem.addEquation(eq2)
+
+        assertEquals(2, equationSystem.equations.size)
+        assertTrue(equationSystem.variables.containsAll(listOf("x", "v", "a", "t")))
+        assertTrue(equationSystem.derivativeVariables.contains("x"))
+    }
+}
--- a/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/EventsAndActionsTest.kt
+++ b/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/EventsAndActionsTest.kt
@ -0,0 +1,73 @@
+package space.kscience.controls.constructor
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import space.kscience.controls.constructor.dsl.core.events.Event
+import space.kscience.controls.constructor.dsl.core.events.ReinitAction
+import space.kscience.controls.constructor.dsl.core.events.AssignAction
+import space.kscience.controls.constructor.dsl.core.expressions.BinaryExpression
+import space.kscience.controls.constructor.dsl.core.expressions.BinaryOperator
+import space.kscience.controls.constructor.dsl.core.expressions.ConstantExpression
+import space.kscience.controls.constructor.dsl.core.expressions.VariableExpression
+import space.kscience.controls.constructor.dsl.core.simulation.SimulationContext
+import space.kscience.controls.constructor.dsl.core.units.Units
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.runTest
+
+class EventsAndActionsTest {
+
+    @Test
+    fun testCreatingEvents() {
+        val xVar = Variable("x", Units.meter)
+        val xExpr = VariableExpression(xVar)
+
+        val condition = BinaryExpression(xExpr, BinaryOperator.GREATER_THAN, ConstantExpression(10.0, Units.meter))
+        val action = AssignAction(xVar, ConstantExpression(0.0, Units.meter))
+
+        val event = Event(condition, listOf(action))
+
+        assertEquals(condition, event.condition)
+        assertEquals(1, event.actions.size)
+        assertEquals(action, event.actions[0])
+    }
+
+    @Test
+    fun testProcessingEventsInSimulation() = runTest {
+        val xVar = Variable("x", Units.meter)
+        val xExpr = VariableExpression(xVar)
+        val context = SimulationContext(CoroutineScope(Dispatchers.Default)).apply {
+            registerVariable(xVar) // Регистрация переменной
+            launch { updateVariable("x", 5.0) } // Установка начального значения переменной
+        }
+
+        val condition = BinaryExpression(xExpr, BinaryOperator.GREATER_THAN, ConstantExpression(10.0, Units.meter))
+        val action = AssignAction(xVar, ConstantExpression(0.0, Units.meter))
+        val event = Event(condition, listOf(action))
+
+        context.events.add(event)
+
+        // Simulate x crossing the threshold
+        context.updateVariable("x", 15.0)
+        context.handleEvents()
+
+        assertEquals(0.0, context.getCurrentVariableValue("x"))
+    }
+
+    @Test
+    fun testReinitAction() = runTest {
+        val vVar = Variable("v", Units.meter / Units.second)
+        val vExpr = VariableExpression(vVar)
+        val context = SimulationContext(CoroutineScope(Dispatchers.Default)).apply {
+            registerVariable(vVar) // Регистрация переменной
+            launch { updateVariable("v", 20.0) } // Установка начального значения переменной
+        }
+
+        val action = ReinitAction(vVar, ConstantExpression(0.0, Units.meter / Units.second))
+        action.execute(context)
+
+        assertEquals(0.0, context.getCurrentVariableValue("v"))
+    }
+}
--- a/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/ExpressionsTest.kt
+++ b/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/ExpressionsTest.kt
@ -0,0 +1,101 @@
+package space.kscience.controls.constructor
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+import kotlin.test.assertTrue
+import space.kscience.controls.constructor.dsl.core.expressions.*
+import space.kscience.controls.constructor.dsl.core.units.Units
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+class ExpressionsTest {
+
+    @Test
+    fun testCreationOfDifferentTypesOfExpressions() {
+        // Constant expression
+        val constExpr = ConstantExpression(5.0, Units.meter)
+        assertEquals(5.0, constExpr.value)
+        assertEquals(Units.meter, constExpr.unit)
+
+        // Variable expression
+        val speedVar = Variable("speed", Units.meter / Units.second)
+        val speedExpr = VariableExpression(speedVar)
+        assertEquals(speedVar, speedExpr.variable)
+        assertEquals(Units.meter / Units.second, speedExpr.unit)
+
+        // Binary expression (addition)
+        val distanceVar = Variable("distance", Units.meter)
+        val distanceExpr = VariableExpression(distanceVar)
+        val totalDistanceExpr = BinaryExpression(distanceExpr, BinaryOperator.ADD, constExpr)
+        assertEquals(Units.meter, totalDistanceExpr.unit)
+
+        // Function call expression
+        val sinExpr = FunctionCallExpression("sin", listOf(constExpr))
+        assertEquals(Units.dimensionless, sinExpr.unit)
+    }
+
+    @Test
+    fun testEvaluationOfExpressions() {
+        val xVar = Variable("x", Units.meter)
+        val xExpr = VariableExpression(xVar)
+        val constExpr = ConstantExpression(2.0, Units.meter)
+
+        val values = mapOf("x" to 3.0)
+
+        // Binary expression: x + 2
+        val sumExpr = BinaryExpression(xExpr, BinaryOperator.ADD, constExpr)
+        assertEquals(5.0, sumExpr.evaluate(values))
+
+        // Binary expression: x * 2
+        val mulExpr = BinaryExpression(xExpr, BinaryOperator.MULTIPLY, ConstantExpression(2.0, Units.dimensionless))
+        assertEquals(6.0, mulExpr.evaluate(values))
+
+        // Function call: sin(x)
+        val sinExpr = FunctionCallExpression("sin", listOf(xExpr))
+        assertEquals(kotlin.math.sin(3.0), sinExpr.evaluate(values))
+    }
+
+    @Test
+    fun testDimensionCheckingInExpressions() {
+        val lengthVar = Variable("length", Units.meter)
+        val timeVar = Variable("time", Units.second)
+        val lengthExpr = VariableExpression(lengthVar)
+        val timeExpr = VariableExpression(timeVar)
+
+        // Correct addition
+        val sumExpr = BinaryExpression(lengthExpr, BinaryOperator.ADD, ConstantExpression(5.0, Units.meter))
+        assertFailsWith<Exception> {
+            sumExpr.checkDimensions()
+        }
+
+        // Incorrect addition (length + time)
+        val invalidSumExpr = BinaryExpression(lengthExpr, BinaryOperator.ADD, timeExpr)
+        val exception = assertFailsWith<IllegalArgumentException> {
+            invalidSumExpr.checkDimensions()
+        }
+        assertEquals("Units must be the same for addition or subtraction.", exception.message)
+    }
+
+    @Test
+    fun testDerivativeOfExpressions() {
+        val xVar = Variable("x", Units.meter)
+        val xExpr = VariableExpression(xVar)
+        val constExpr = ConstantExpression(5.0, Units.meter)
+
+        // Derivative of constant: should be zero
+        val derivativeConst = constExpr.derivative(xExpr)
+        assertTrue(derivativeConst is ConstantExpression)
+        assertEquals(0.0, derivativeConst.value)
+
+        // Derivative of variable with respect to itself: should be one
+        val derivativeVar = xExpr.derivative(xExpr)
+        assertTrue(derivativeVar is ConstantExpression)
+        assertEquals(1.0, derivativeVar.value)
+
+        // Derivative of x + 5 with respect to x: should be one
+        val sumExpr = BinaryExpression(xExpr, BinaryOperator.ADD, constExpr)
+        val derivativeSum = sumExpr.derivative(xExpr)
+        assertTrue(derivativeSum is ConstantExpression)
+        assertEquals(1.0, derivativeSum.value)
+    }
+}
--- a/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/FunctionsTest.kt
+++ b/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/FunctionsTest.kt
@ -0,0 +1,29 @@
+package space.kscience.controls.constructor
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import space.kscience.controls.constructor.dsl.core.functions.FunctionBuilder
+import space.kscience.controls.constructor.dsl.core.expressions.*
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+import space.kscience.controls.constructor.dsl.core.units.Units
+
+class FunctionsTest {
+
+    @Test
+    fun testCreatingFunctions() {
+        val functionBuilder = FunctionBuilder("add").apply {
+            val aVar = input("a", Units.dimensionless)
+            val bVar = input("b", Units.dimensionless)
+            val resultVar = output("result", Units.dimensionless)
+
+            algorithm {
+                assign(resultVar, BinaryExpression(VariableExpression(aVar), BinaryOperator.ADD, VariableExpression(bVar)))
+            }
+        }
+
+        val addFunction = functionBuilder.build()
+        assertEquals("add", addFunction.name)
+        assertEquals(2, addFunction.inputs.size)
+        assertEquals(1, addFunction.outputs.size)
+    }
+}
--- a/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/UnitsTest.kt
+++ b/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/UnitsTest.kt
@ -0,0 +1,85 @@
+package space.kscience.controls.constructor
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+import space.kscience.controls.constructor.dsl.core.units.Dimension
+import space.kscience.controls.constructor.dsl.core.units.PhysicalUnit
+import space.kscience.controls.constructor.dsl.core.units.Units
+
+class UnitsTest {
+
+    @Test
+    fun testCreationOfBaseUnits() {
+        val meter = Units.meter
+        assertEquals("meter", meter.name)
+        assertEquals("m", meter.symbol)
+        assertEquals(1.0, meter.conversionFactorToSI)
+        assertEquals(Dimension(length = 1.0), meter.dimension)
+
+        val kilogram = Units.kilogram
+        assertEquals("kilogram", kilogram.name)
+        assertEquals("kg", kilogram.symbol)
+        assertEquals(1.0, kilogram.conversionFactorToSI)
+        assertEquals(Dimension(mass = 1.0), kilogram.dimension)
+
+        val second = Units.second
+        assertEquals("second", second.name)
+        assertEquals("s", second.symbol)
+        assertEquals(1.0, second.conversionFactorToSI)
+        assertEquals(Dimension(time = 1.0), second.dimension)
+    }
+
+    @Test
+    fun testArithmeticOperationsOnUnits() {
+        val meter = Units.meter
+        val second = Units.second
+        val kilogram = Units.kilogram
+
+        val velocityUnit = meter / second
+        assertEquals(Dimension(length = 1.0, time = -1.0), velocityUnit.dimension)
+        assertEquals("m/s", velocityUnit.symbol)
+
+        val accelerationUnit = meter / (second * second)
+        assertEquals(Dimension(length = 1.0, time = -2.0), accelerationUnit.dimension)
+        assertEquals("m/s^2", accelerationUnit.symbol)
+
+        val forceUnit = kilogram * accelerationUnit
+        assertEquals(Dimension(mass = 1.0, length = 1.0, time = -2.0), forceUnit.dimension)
+        assertEquals("kg*m/s^2", forceUnit.symbol)
+    }
+
+    @Test
+    fun testUnitCompatibilityForAdditionAndSubtraction() {
+        val meter = Units.meter
+        val kilogram = Units.kilogram
+
+        // Correct addition
+        val length1 = meter
+        val length2 = meter
+        assertEquals(length1.dimension, length2.dimension)
+
+        // Incorrect addition should throw exception
+        val mass = kilogram
+        val exception = assertFailsWith<IllegalArgumentException> {
+            if (length1.dimension != mass.dimension) {
+                throw IllegalArgumentException("Units are not compatible for addition.")
+            }
+        }
+        assertEquals("Units are not compatible for addition.", exception.message)
+    }
+
+    @Test
+    fun testUnitConversion() {
+        val kilometer = PhysicalUnit("kilometer", "km", 1000.0, Units.meter.dimension)
+        val centimeter = PhysicalUnit("centimeter", "cm", 0.01, Units.meter.dimension)
+
+        // Convert 1 km to meters
+        val kmInMeters = 1.0 * kilometer.conversionFactorToSI
+        assertEquals(1000.0, kmInMeters)
+
+        // Convert 100 cm to meters
+        val cmInMeters = 100.0 * centimeter.conversionFactorToSI
+        assertEquals(1.0, cmInMeters)
+    }
+}
--- a/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/VariablesTest.kt
+++ b/controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/VariablesTest.kt
@ -0,0 +1,41 @@
+package space.kscience.controls.constructor
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+import kotlin.test.assertNull
+import space.kscience.controls.constructor.dsl.core.units.Units
+import space.kscience.controls.constructor.dsl.core.variables.ParameterVariable
+import space.kscience.controls.constructor.dsl.core.variables.Variable
+
+class VariablesTest {
+
+    @Test
+    fun testCreationOfVariablesAndParameters() {
+        val length = Variable("length", Units.meter)
+        assertEquals("length", length.name)
+        assertEquals(Units.meter, length.unit)
+        assertNull(length.value)
+
+        val mass = ParameterVariable("mass", Units.kilogram, value = 10.0)
+        assertEquals("mass", mass.name)
+        assertEquals(Units.kilogram, mass.unit)
+        assertEquals(10.0, mass.value)
+    }
+
+    @Test
+    fun testSettingAndGettingValuesOfVariablesAndParameters() {
+        val speed = Variable("speed", Units.meter / Units.second)
+        speed.value = 15.0
+        assertEquals(15.0, speed.value)
+
+        val density = ParameterVariable("density", Units.kilogram / Units.meter.pow(3.0), value = 1000.0)
+        assertEquals(1000.0, density.value)
+
+        // Attempt to create a parameter with value outside the allowed range
+        val exception = assertFailsWith<IllegalArgumentException> {
+            ParameterVariable("temperature", Units.kelvin, value = -10.0, min = 0.0)
+        }
+        assertEquals("Value of parameter temperature is less than minimum allowed value.", exception.message)
+    }
+}