question: public static String matrixToString ( double [ ] [ ] matrix ) { StringBuffer result = new StringBuffer ( ) ; int last = matrix . length - 1 ; for ( int i = 0 ; i <= last ; i ++ ) { for ( int j = 0 ; j <= last ; j ++ ) { result . append ( Utils . doubleToString ( matrix [ i ] [ j ] , 6 , 2 ) + " " ) ; if ( j == last ) { result . append ( '\n' ) ; } } } return result . toString ( ) ; }
target:  Return a matrix as a String