code: public SDVariable mmul(SDVariable x, SDVariable y, MMulTranspose transpose) {
          return mmul(null, x, y, transpose);
  
      }
docs: Matrix multiplication: out = mmul(x,y)<br>
  Supports specifying a {@link MMulTranspose} argument to perform operation such as mmul(a^T, b), etc.
  
  @param x         First input variable
  @param y         Second input variable
  @param transpose Transpose arguments
  @return Output variable