Enhanced tests of Double substitution.

kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/LabeledPolynomial.kt

@@ -6,7 +6,8 @@
 package space.kscience.kmath.functions
 
 import space.kscience.kmath.expressions.Symbol
-import space.kscience.kmath.operations.*
+import space.kscience.kmath.operations.Ring
+import space.kscience.kmath.operations.ScaleOperations
 import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
 import kotlin.experimental.ExperimentalTypeInference
@@ -269,6 +270,13 @@ public class LabeledPolynomialSpace<C, A : Ring<C>>(
                 }
         )
 
+    /**
+     * Converts the integer [value] to polynomial.
+     */
+    public override fun number(value: Int): LabeledPolynomial<C> =
+        if (value == 0) zero
+        else LabeledPolynomial(mapOf(emptyMap<Symbol, UInt>() to constantNumber(value)))
+
     public operator fun C.plus(other: Symbol): LabeledPolynomial<C> =
         if (isZero()) LabeledPolynomial<C>(mapOf(
             mapOf(other to 1U) to constantOne,

kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/ListPolynomial.kt

@@ -5,7 +5,9 @@
 
 package space.kscience.kmath.functions
 
-import space.kscience.kmath.operations.*
+import space.kscience.kmath.operations.Ring
+import space.kscience.kmath.operations.ScaleOperations
+import space.kscience.kmath.operations.invoke
 import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
 import kotlin.experimental.ExperimentalTypeInference
@@ -13,6 +15,7 @@ import kotlin.jvm.JvmName
 import kotlin.math.max
 import kotlin.math.min
 
+
 /**
  * Polynomial model without fixation on specific context they are applied to.
  *
@@ -193,6 +196,13 @@ public open class ListPolynomialSpace<C, A : Ring<C>>(
                 }
         )
 
+    /**
+     * Converts the integer [value] to polynomial.
+     */
+    public override fun number(value: Int): ListPolynomial<C> =
+        if (value == 0) zero
+        else ListPolynomial(constantNumber(value))
+
     /**
      * Returns sum of the constant represented as polynomial and the polynomial.
      */

kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/NumberedPolynomial.kt

@@ -5,7 +5,8 @@
 
 package space.kscience.kmath.functions
 
-import space.kscience.kmath.operations.*
+import space.kscience.kmath.operations.Ring
+import space.kscience.kmath.operations.ScaleOperations
 import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
 import kotlin.experimental.ExperimentalTypeInference
@@ -221,6 +222,13 @@ public open class NumberedPolynomialSpace<C, A : Ring<C>>(
                 }
         )
 
+    /**
+     * Converts the integer [value] to polynomial.
+     */
+    public override fun number(value: Int): NumberedPolynomial<C> =
+        if (value == 0) zero
+        else NumberedPolynomial(mapOf(emptyList<UInt>() to constantNumber(value)))
+
     /**
      * Returns sum of the constant represented as polynomial and the polynomial.
      */

kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/Polynomial.kt

@@ -61,6 +61,11 @@ public interface PolynomialSpace<C, P: Polynomial<C>> : Ring<P> {
      */
     public operator fun Int.times(other: C): C
 
+    /**
+     * Converts the integer [value] to constant.
+     */
+    public fun constantNumber(value: Int): C = constantOne * value
+
     /**
      * Returns sum of the polynomial and the integer represented as polynomial.
      *
@@ -99,6 +104,11 @@ public interface PolynomialSpace<C, P: Polynomial<C>> : Ring<P> {
      */
     public operator fun Int.times(other: P): P = multiplyBySquaring(other, this)
 
+    /**
+     * Converts the integer [value] to polynomial.
+     */
+    public fun number(value: Int): P = one * value
+
     /**
      * Returns the same constant.
      */

kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/RationalFunction.kt

@@ -68,6 +68,11 @@ public interface RationalFunctionalSpace<C, P: Polynomial<C>, R: RationalFunctio
      */
     public operator fun Int.times(other: C): C
 
+    /**
+     * Converts the integer [value] to constant.
+     */
+    public fun constantNumber(value: Int): C = constantOne * value
+
     /**
      * Returns sum of the constant and the integer represented as polynomial.
      *
@@ -106,6 +111,11 @@ public interface RationalFunctionalSpace<C, P: Polynomial<C>, R: RationalFunctio
      */
     public operator fun Int.times(other: P): P
 
+    /**
+     * Converts the integer [value] to polynomial.
+     */
+    public fun polynomialNumber(value: Int): P = polynomialOne * value
+
     /**
      * Returns sum of the rational function and the integer represented as rational function.
      *
@@ -144,6 +154,11 @@ public interface RationalFunctionalSpace<C, P: Polynomial<C>, R: RationalFunctio
      */
     public operator fun Int.times(other: R): R = multiplyBySquaring(other, this)
 
+    /**
+     * Converts the integer [value] to rational function.
+     */
+    public fun number(value: Int): R = one * value
+
     /**
      * Returns the same constant.
      */
@@ -672,6 +687,11 @@ public interface RationalFunctionalSpaceOverPolynomialSpace<
      */
     public override operator fun Int.times(other: P): P = polynomialRing { this@times * other }
 
+    /**
+     * Converts the integer [value] to polynomial.
+     */
+    public override fun polynomialNumber(value: Int): P = polynomialRing { number(value) }
+
     /**
      * Returns the same constant.
      */
@@ -880,7 +900,7 @@ public abstract class PolynomialSpaceOfFractions<
         P: Polynomial<C>,
         R: RationalFunction<C, P>,
         > : RationalFunctionalSpace<C, P, R> {
-    protected abstract fun constructRationalFunction(numerator: P, denominator: P) : R
+    protected abstract fun constructRationalFunction(numerator: P, denominator: P = polynomialOne) : R
 
     /**
      * Returns sum of the rational function and the integer represented as rational function.
@@ -944,6 +964,11 @@ public abstract class PolynomialSpaceOfFractions<
             other.denominator
         )
 
+    /**
+     * Converts the integer [value] to rational function.
+     */
+    public override fun number(value: Int): R = constructRationalFunction(polynomialNumber(value))
+
     /**
      * Returns sum of the constant represented as rational function and the rational function.
      */
@@ -1076,10 +1101,10 @@ public abstract class PolynomialSpaceOfFractions<
     /**
      * Instance of zero rational function (zero of the rational functions ring).
      */
-    public override val zero: R get() = constructRationalFunction(polynomialZero, polynomialOne)
+    public override val zero: R get() = constructRationalFunction(polynomialZero)
 
     /**
      * Instance of unit polynomial (unit of the rational functions ring).
      */
-    public override val one: R get() = constructRationalFunction(polynomialOne, polynomialOne)
+    public override val one: R get() = constructRationalFunction(polynomialOne)
 }