code: private void set(Matrix m)
      {
          this.nRows  = this.nCols = Math.min(m.nRows, m.nCols);
          this.values = m.values;
      }
docs: Set this square matrix from another matrix.  Note that this
  matrix will reference the values of the argument matrix.  If
  the values are not square, only the upper left square is used.
  @param values the 2-d array of values