std.fb

func bitwise(matrix m, matrix n) {
	double k =0.0;
	int i = 0;
	int j = 0;
	for (i = 0; i<3; i=i+1){
		for (j = 0; j<3; j=j+1){
		 k = k + m[i,j]*n[i,j];
		}
	}
	return k;
}



func filter(matrix m, matrix n) {
	int a;
	int b;
	int c;
	int d;
	a,b = size(m);
	c,d = size(n);
	if (c == 3) {
	matrix t = zeros(a+2,b+2);
	matrix r = zeros(a,b);
	t[1:a,1:b] = m[0:a-1,0:b-1];
	int i = 0;
	int j = 0;
	for (i = 0; i<a; i=i+1){
		for (j = 0; j<b; j=j+1){
		 double k = 0.0;
		 k = bitwise(t[i:i+2,j:j+2],n);
		 r[i,j] = k;
		}
	}
	return r;
	}
	if (c == 5) {
	matrix t = zeros(a+4,b+4);
	matrix r = zeros(a,b);
	t[2:a+1,2:b+1] = m[0:a-1,0:b-1];
	int i = 0;
	int j = 0;
	for (i = 0; i<a; i=i+1){
		for (j = 0; j<b; j=j+1){
		 double k = 0.0;
		 k = bitwise(t[i:i+4,j:j+4],n);
		 r[i,j] = k;
		}
	}
	return r;
	} 
}