root/test/correctness/iterate_over_circle.cpp

DEFINITIONS

1. my_trace
2. main

#include "Halide.h"
#include <stdio.h>

using namespace Halide;

int count = 0;
int my_trace(void *user_context, const halide_trace_event_t *ev) {
    if (ev->event == halide_trace_load) {
        count++;
    }
    return 0;
}

int main(int argc, char **argv) {

    Func f;
    Var x, y;

    Func in;
    in(x, y) = x + y;
    in.compute_root();

    // Set f to zero
    f(x, y) = 0;

    // Then iterate over a circle, adding in(x, y) to f.
    Expr t = cast<int>(ceil(sqrt(10*10 - y*y)));
    f(x, y) += select(x > -t && x < t, in(x, y), 0);

    in.trace_loads();
    f.set_custom_trace(my_trace);
    f.realize(20, 20);

    int c = 0;
    for (int y = 0; y < 20; y++) {
        for (int x = 0; x < 20; x++) {
            if (x*x + y*y < 10*10) c++;
        }
    }

    if (count != c) {
        printf("Func 'in' should only have been loaded from at points "
               "within the circle x*x + y*y < 10*10. It was loaded %d "
               "times, but there are %d points within that circle\n", count, c);
        return -1;
    }

    printf("Success!\n");

    return 0;
}