public static double[][] halfkernels( final double[] sigma ) { final int n = sigma.length; final double[][] halfkernels = new double[ n ][]; final int[] size = halfkernelsizes( sigma ); for ( int i = 0; i < n; ++i ) halfkernels[ i ] = halfkernel( sigma[ i ], size[ i ], true ); return halfkernels; }