code: public SDVariable mmul(String name, SDVariable x, SDVariable y, MMulTranspose transpose) {
          validateNumerical("matrix multiplication (mmul)", x, y);
          SDVariable result = f().mmul(x, y, transpose);
          return updateVariableNameAndReference(result, name);
      }
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 name      Output variable name
  @param x         First input variable
  @param y         Second input variable
  @param transpose Transpose arguments
  @return Output variable