question: public static Matrix constructWithCopy ( double [ ] [ ] A ) { int m = A . length ; int n = A [ 0 ] . length ; Matrix X = new Matrix ( m , n ) ; double [ ] [ ] C = X . getArray ( ) ; for ( int i = 0 ; i < m ; i ++ ) { if ( A [ i ] . length != n ) { throw new IllegalArgumentException ( "All rows must have the same length." ) ; } for ( int j = 0 ; j < n ; j ++ ) { C [ i ] [ j ] = A [ i ] [ j ] ; } } return X ; }
target:  Construct a matrix from a copy of a 2-D array.