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Refactor integrator API.

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This commit is contained in:
Alexander Nozik 2021-05-16 13:59:37 +03:00
parent 4964fb2642
commit 6f39b38a72
6 changed files with 28 additions and 34 deletions
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4
examples/src/main/kotlin/space/kscience/kmath/functions/integrate.kt
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@ -5,8 +5,6 @@
package space.kscience.kmath.functions
import space.kscience.kmath.integration.integrate
import space.kscience.kmath.integration.value
import space.kscience.kmath.operations.DoubleField
import kotlin.math.pow
@ -18,5 +16,5 @@ fun main() {
val result = DoubleField.integrate(0.0..10.0, function = function)
//the value is nullable because in some cases the integration could not succeed
println(result.value)
println(result.valueOrNull)
}

4
examples/src/main/kotlin/space/kscience/kmath/functions/matrixIntegration.kt
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@ -5,8 +5,6 @@
package space.kscience.kmath.functions
import space.kscience.kmath.integration.integrate
import space.kscience.kmath.integration.value
import space.kscience.kmath.nd.StructureND
import space.kscience.kmath.nd.nd
import space.kscience.kmath.operations.DoubleField
@ -27,6 +25,6 @@ fun main(): Unit = DoubleField {
val result = integrate(0.0..10.0, function = function)
//the value is nullable because in some cases the integration could not succeed
println(result.value)
println(result.valueOrNull)
}
}

2
kmath-commons/src/main/kotlin/space/kscience/kmath/commons/integration/GaussRuleIntegrator.kt
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@ -78,6 +78,6 @@ public class GaussRuleIntegrator(
function: (Double) -> Double,
): Double = GaussRuleIntegrator(numPoints, type).integrate(
UnivariateIntegrand(function, IntegrationRange(range))
).value!!
).valueOrNull!!
}
}

20
kmath-functions/src/commonMain/kotlin/space/kscience/kmath/integration/GaussIntegrator.kt
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@ -66,31 +66,25 @@ public class GaussIntegrator<T : Any>(
return integrand + IntegrandValue(res) + IntegrandCallsPerformed(integrand.calls + points.size)
}
public companion object {
}
public companion object
}
/**
* Integrate [T]-valued univariate function using provided set of [IntegrandFeature]
* Following features are evaluated:
* Create a Gauss-Legendre integrator for this field
* Following integrand features are accepted:
* * [GaussIntegratorRuleFactory] - A factory for computing the Gauss integration rule. By default uses [GaussLegendreRuleFactory]
* * [IntegrationRange] - the univariate range of integration. By default uses 0..1 interval.
* * [IntegrandMaxCalls] - the maximum number of function calls during integration. For non-iterative rules, always uses the maximum number of points. By default uses 10 points.
* * [UnivariateIntegrandRanges] - Set of ranges and number of points per range. Defaults to given [IntegrationRange] and [IntegrandMaxCalls]
*/
@UnstableKMathAPI
public fun <T : Any> Field<T>.integrate(
vararg features: IntegrandFeature,
function: (Double) -> T,
): UnivariateIntegrand<T> = GaussIntegrator(this).integrate(UnivariateIntegrand(function, *features))
public val <T:Any> Field<T>.integrator: GaussIntegrator<T> get() = GaussIntegrator(this)
/**
* Use [GaussIntegrator.Companion.integrate] to integrate the function in the current algebra with given [range] and [numPoints]
* Use [integrate] to integrate the function in the current algebra with given [range] and [numPoints]
*/
@UnstableKMathAPI
public fun <T : Any> Field<T>.integrate(
public fun <T : Any> GaussIntegrator<T>.integrate(
range: ClosedRange<Double>,
order: Int = 10,
intervals: Int = 10,
@ -104,7 +98,7 @@ public fun <T : Any> Field<T>.integrate(
val ranges = UnivariateIntegrandRanges(
(0 until intervals).map { i -> (rangeSize * i)..(rangeSize * (i + 1)) to order }
)
return GaussIntegrator(this).integrate(
return integrate(
UnivariateIntegrand(
function,
IntegrationRange(range),

28
kmath-functions/src/commonMain/kotlin/space/kscience/kmath/integration/UnivariateIntegrand.kt
View File

@ -35,37 +35,41 @@ public typealias UnivariateIntegrator<T> = Integrator<UnivariateIntegrand<T>>
@JvmInline
public value class IntegrationRange(public val range: ClosedRange<Double>) : IntegrandFeature
public val <T : Any> UnivariateIntegrand<T>.value: T? get() = getFeature<IntegrandValue<T>>()?.value
/**
* Value of the integrand if it is present or null
*/
public val <T : Any> UnivariateIntegrand<T>.valueOrNull: T? get() = getFeature<IntegrandValue<T>>()?.value
/**
* Value of the integrand or error
*/
public val <T : Any> UnivariateIntegrand<T>.value: T get() = valueOrNull ?: error("No value in the integrand")
/**
* A shortcut method to integrate a [function] in [range] with additional [features].
* The [function] is placed in the end position to allow passing a lambda.
*/
@UnstableKMathAPI
public fun UnivariateIntegrator<Double>.integrate(
public fun <T: Any> UnivariateIntegrator<T>.integrate(
range: ClosedRange<Double>,
vararg features: IntegrandFeature,
function: (Double) -> Double,
): Double = integrate(
UnivariateIntegrand(function, IntegrationRange(range), *features)
).value ?: error("Unexpected: no value after integration.")
function: (Double) -> T,
): UnivariateIntegrand<T> = integrate(UnivariateIntegrand(function, IntegrationRange(range), *features))
/**
* A shortcut method to integrate a [function] in [range] with additional [features].
* The [function] is placed in the end position to allow passing a lambda.
*/
@UnstableKMathAPI
public fun UnivariateIntegrator<Double>.integrate(
public fun <T: Any> UnivariateIntegrator<T>.integrate(
range: ClosedRange<Double>,
featureBuilder: MutableList<IntegrandFeature>.() -> Unit = {},
function: (Double) -> Double,
): Double {
function: (Double) -> T,
): UnivariateIntegrand<T> {
//TODO use dedicated feature builder class instead or add extensions to MutableList<IntegrandFeature>
val features = buildList {
featureBuilder()
add(IntegrationRange(range))
}
return integrate(
UnivariateIntegrand(function, *features.toTypedArray())
).value ?: error("Unexpected: no value after integration.")
return integrate(UnivariateIntegrand(function, *features.toTypedArray()))
}

4
kmath-functions/src/commonTest/kotlin/space/kscience/kmath/integration/GaussIntegralTest.kt
View File

@ -19,7 +19,7 @@ class GaussIntegralTest {
val res = DoubleField.integrate(0.0..2 * PI) { x ->
sin(x)
}
assertEquals(0.0, res.value!!, 1e-2)
assertEquals(0.0, res.valueOrNull!!, 1e-2)
}
@Test
@ -31,7 +31,7 @@ class GaussIntegralTest {
0.0
}
}
assertEquals(20.0, res.value!!, 0.5)
assertEquals(20.0, res.valueOrNull!!, 0.5)
}