code: public void reshape( int numRows , int numCols ) {
          if( mat.getType().isFixed() ) {
              throw new IllegalArgumentException("Can't reshape a fixed sized matrix");
          } else {
              ((ReshapeMatrix)mat).reshape(numRows, numCols);
          }
      }
docs: <p>
  Reshapes the matrix to the specified number of rows and columns.  If the total number of elements
  is &le; number of elements it had before the data is saved.  Otherwise a new internal array is
  declared and the old data lost.
  </p>
  
  <p>
  This is equivalent to calling A.getMatrix().reshape(numRows,numCols,false).
  </p>
  
  @see DMatrixRMaj#reshape(int,int,boolean)
  
  @param numRows The new number of rows in the matrix.
  @param numCols The new number of columns in the matrix.