public static String format(double[][] d) {
    return d == null ? "null" : (d.length == 0) ? "[]" : //
        formatTo(new StringBuilder().append("[\n"), d, " [", "]\n", ", ", NF2).append(']').toString();
  }
public static String format ( double [ ] [ ] d ) { return d == null ? "null" : ( d . length == 0 ) ? "[]" : formatTo ( new StringBuilder ( ) . append ( "[\n" ) , d , " [" , "]\n" , ", " , NF2 ) . append ( ']' ) . toString ( ) ; }
Formats the double array d with ',' as separator and 2 fraction digits.

@param d the double array to be formatted
@return a String representing the double array d