code: public ColumnVector getColumn(int c) throws MatrixException
      {
          if ((c < 0) || (c >= nCols)) {
              throw new MatrixException(MatrixException.INVALID_INDEX);
          }
  
          ColumnVector cv = new ColumnVector(nRows);
          for (int r = 0; r < nRows; ++r) {
              cv.values[r][0] = this.values[r][c];
          }
  
          return cv;
      }
docs: Get a column of this matrix.
  @param c the column index
  @return the column as a column vector
  @throws numbercruncher.MatrixException for an invalid index