code: @Override
      public INDArray mmul(INDArray other, INDArray result, MMulTranspose mMulTranspose) {
          return null;
      }
docs: Perform an copy matrix multiplication
  
  @param other         the other matrix to perform matrix multiply with
  @param result        the result ndarray
  @param mMulTranspose the transpose status of each array
  @return the result of the matrix multiplication