# Module kmath-nd4j

ND4J based implementations of KMath abstractions.

 - [nd4jarraystructure](#) : NDStructure wrapper for INDArray
 - [nd4jarrayrings](#) : Rings over Nd4jArrayStructure of Int and Long
 - [nd4jarrayfields](#) : Fields over Nd4jArrayStructure of Float and Double


## Artifact:

The Maven coordinates of this project are `space.kscience:kmath-nd4j:0.3.0-dev-6`.

**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
}

dependencies {
    implementation 'space.kscience:kmath-nd4j:0.3.0-dev-6'
}
```
**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
}

dependencies {
    implementation("space.kscience:kmath-nd4j:0.3.0-dev-6")
}
```

## 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).asDoubleStructure()
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 = DoubleNd4jArrayField(intArrayOf(2, 2))
val array = Nd4j.rand(2, 2).asDoubleStructure()

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).