Example code for https://github.com/deeplearning4j/nd4j/issues/1916#issuecomment-314520715

Nd4jIndexAccumOps.scala

import org.nd4s.Implicits._
import org.nd4j.linalg.factory.Nd4j
import org.nd4j.linalg.api.ops.impl.indexaccum.IAMax


object IndexAccumOpsMain {

  def main(args: Array[String]) {

    /** Gist for https://github.com/deeplearning4j/nd4j/issues/1916#issuecomment-314520715 **/

    val myArray = Array(
      Array(0,8,4),
      Array(5,3,5),
      Array(2,3,6)).toNDArray

    val iAMaxAlongRows = Nd4j.getExecutioner().exec(new IAMax(myArray), 0)
    val iAMaxAlongColumns = Nd4j.getExecutioner().exec(new IAMax(myArray), 1)

    println(s"3x3 array:\n$myArray")
    println(s"argmax of absolute values along dimension 0:\n$iAMaxAlongRows")
    println(s"argmax of absolute values along dimension 1:\n$iAMaxAlongColumns")
  }
}