code: public static void swapRows(double[][] matrix, int row1, int row2) {
  		double[] temp = matrix[row1];
  		matrix[row1] = matrix[row2];
  		matrix[row2] = temp;
  	}
docs: Swap components in the two rows.
  
  @param matrix
  the matrix to modify
  @param row1
  the first row
  @param row2
  the second row