public static double [ ] colSums ( double [ ] [ ] data ) { double [ ] x = data [ 0 ] . clone ( ) ; for ( int i = 1 ; i < data . length ; i ++ ) { for ( int j = 0 ; j < x . length ; j ++ ) { x [ j ] += data [ i ] [ j ] ; } } return x ; }
Returns the column sums for a matrix .