code: @Override
      public int iamin(INDArray arr) {
          switch (arr.data().dataType()) {
              case DOUBLE:
                  DefaultOpExecutioner.validateDataType(DataType.DOUBLE, arr);
                  return idamin(arr.length(), arr, 1);
              case FLOAT:
                  DefaultOpExecutioner.validateDataType(DataType.FLOAT, arr);
                  return isamin(arr.length(), arr, 1);
              case HALF:
                  DefaultOpExecutioner.validateDataType(DataType.HALF, arr);
                  return ihamin(arr.length(), arr, 1);
              default:
          }
          throw new UnsupportedOperationException();
      }
docs: Find the index of the element with maximum absolute value
  
  @param arr a vector
  @return the index of the element with minimum absolute value