kmath/kmath-nd4j/README.md
2021-02-19 10:52:56 +03:00

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# ND4J NDStructure implementation (`kmath-nd4j`)
This subproject implements the following features:
- [nd4jarraystructure](src/commonMain/kotlin/kscience/kmath/operations/Algebra.kt) : NDStructure wrapper for INDArray
- [nd4jarrayrings](src/commonMain/kotlin/kscience/kmath/structures/NDStructure.kt) : Rings over Nd4jArrayStructure of Int and Long
- [nd4jarrayfields](src/commonMain/kotlin/kscience/kmath/structures/Buffers.kt) : Fields over Nd4jArrayStructure of Float and Double
> #### Artifact:
>
> This module artifact: `space.kscience:kmath-nd4j:0.2.0-dev-7`.
>
> Bintray release version: [ ![Download](https://api.bintray.com/packages/mipt-npm/kscience/kmath-nd4j/images/download.svg) ](https://bintray.com/mipt-npm/kscience/kmath-nd4j/_latestVersion)
>
> Bintray development version: [ ![Download](https://api.bintray.com/packages/mipt-npm/dev/kmath-nd4j/images/download.svg) ](https://bintray.com/mipt-npm/dev/kmath-nd4j/_latestVersion)
>
> **Gradle:**
>
> ```gradle
> repositories {
> maven { url 'https://repo.kotlin.link' }
> maven { url 'https://dl.bintray.com/hotkeytlt/maven' }
> maven { url "https://dl.bintray.com/kotlin/kotlin-eap" } // include for builds based on kotlin-eap
>// Uncomment if repo.kotlin.link is unavailable
>// maven { url 'https://dl.bintray.com/mipt-npm/kscience' }
>// maven { url 'https://dl.bintray.com/mipt-npm/dev' }
> }
>
> dependencies {
> implementation 'space.kscience:kmath-nd4j:0.2.0-dev-7'
> }
> ```
> **Gradle Kotlin DSL:**
>
> ```kotlin
> repositories {
> maven("https://repo.kotlin.link")
> maven("https://dl.bintray.com/kotlin/kotlin-eap") // include for builds based on kotlin-eap
> maven("https://dl.bintray.com/hotkeytlt/maven") // required for a
>// Uncomment if repo.kotlin.link is unavailable
>// maven("https://dl.bintray.com/mipt-npm/kscience")
>// maven("https://dl.bintray.com/mipt-npm/dev")
> }
>
> dependencies {
> implementation("space.kscience:kmath-nd4j:0.2.0-dev-7")
> }
> ```
## Examples
NDStructure wrapper for INDArray:
```kotlin
import org.nd4j.linalg.factory.*
import scientifik.kmath.nd4j.*
import scientifik.kmath.structures.*
val array = Nd4j.ones(2, 2).asRealStructure()
println(array[0, 0]) // 1.0
array[intArrayOf(0, 0)] = 24.0
println(array[0, 0]) // 24.0
```
Fast element-wise and in-place arithmetics for INDArray:
```kotlin
import org.nd4j.linalg.factory.*
import scientifik.kmath.nd4j.*
import scientifik.kmath.operations.*
val field = RealNd4jArrayField(intArrayOf(2, 2))
val array = Nd4j.rand(2, 2).asRealStructure()
val res = field {
(25.0 / array + 20) * 4
}
println(res.ndArray)
// [[ 250.6449, 428.5840],
// [ 269.7913, 202.2077]]
```
Contributed by [Iaroslav Postovalov](https://github.com/CommanderTvis).