kmath-ast

Performance and visualization extensions to MST API.

  • src/commonMain/kotlin/space/kscience/kmath/ast/parser.kt : Expression language and its parser

  • src/jvmMain/kotlin/space/kscience/kmath/asm/asm.kt : Dynamic MST to JVM bytecode compiler

  • src/jsMain/kotlin/space/kscience/kmath/estree/estree.kt : Dynamic MST to JS compiler

  • src/commonMain/kotlin/space/kscience/kmath/ast/rendering/MathRenderer.kt : Extendable MST rendering

Artifact:

The Maven coordinates of this project are space.kscience:kmath-ast:0.3.0-dev-8.

Gradle:

repositories {
maven { url 'https://repo.kotlin.link' }
mavenCentral()
}

dependencies {
implementation 'space.kscience:kmath-ast:0.3.0-dev-8'
}

Gradle Kotlin DSL:

repositories {
maven("https://repo.kotlin.link")
mavenCentral()
}

dependencies {
implementation("space.kscience:kmath-ast:0.3.0-dev-8")
}

Dynamic expression code generation

On JVM

kmath-ast JVM module supports runtime code generation to eliminate overhead of tree traversal. Code generator builds a special implementation of Expression<T> with implemented invoke function.

For example, the following builder:

import space.kscience.kmath.expressions.*
import space.kscience.kmath.operations.*
import space.kscience.kmath.asm.*

MstField { bindSymbol("x") + 2 }.compileToExpression(DoubleField)

... leads to generation of bytecode, which can be decompiled to the following Java class:

package space.kscience.kmath.asm.generated;

import java.util.Map;

import kotlin.jvm.functions.Function2;
import space.kscience.kmath.asm.internal.MapIntrinsics;
import space.kscience.kmath.expressions.Expression;
import space.kscience.kmath.expressions.Symbol;

public final class AsmCompiledExpression_45045_0 implements Expression<Double> {
private final Object[] constants;

public final Double invoke(Map<Symbol, ? extends Double> arguments) {
return (Double) ((Function2) this.constants[0]).invoke((Double) MapIntrinsics.getOrFail(arguments, "x"), 2);
}

public AsmCompiledExpression_45045_0(Object[] constants) {
this.constants = constants;
}
}

Known issues

  • The same classes may be generated and loaded twice, so it is recommended to cache compiled expressions to avoid class loading overhead.

  • This API is not supported by non-dynamic JVM implementations (like TeaVM and GraalVM) because of using class loaders.

On JS

A similar feature is also available on JS.

import space.kscience.kmath.expressions.*
import space.kscience.kmath.operations.*
import space.kscience.kmath.estree.*

MstField { bindSymbol("x") + 2 }.compileToExpression(DoubleField)

The code above returns expression implemented with such a JS function:

var executable = function (constants, arguments) {
return constants[1](constants[0](arguments, "x"), 2);
};

JS also supports very experimental expression optimization with WebAssembly IR generation. Currently, only expressions inside DoubleField and IntRing are supported.

import space.kscience.kmath.expressions.*
import space.kscience.kmath.operations.*
import space.kscience.kmath.wasm.*

MstField { bindSymbol("x") + 2 }.compileToExpression(DoubleField)

An example of emitted Wasm IR in the form of WAT:

(func $executable (param $0 f64) (result f64)
(f64.add
(local.get $0)
(f64.const 2)
)
)

Known issues

  • ESTree expression compilation uses eval which can be unavailable in several environments.

  • WebAssembly isn't supported by old versions of browsers (see https://webassembly.org/roadmap/).

Rendering expressions

kmath-ast also includes an extensible engine to display expressions in LaTeX or MathML syntax.

Example usage:

import space.kscience.kmath.ast.*
import space.kscience.kmath.ast.rendering.*
import space.kscience.kmath.misc.*

Packages

space.kscience.kmath.asm
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space.kscience.kmath.ast
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common
space.kscience.kmath.ast.rendering
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common
space.kscience.kmath.estree
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js
space.kscience.kmath.wasm
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js