// Pre-compute constants
const int offset = s->filter_size / 2;
const double c1 = 1.0 / (sigma * sqrt(2.0 * M_PI));
- const double c2 = 2.0 * pow(sigma, 2.0);
+ const double c2 = 2.0 * sigma * sigma;
// Compute weights
for (i = 0; i < s->filter_size; i++) {
const int x = i - offset;
- s->weights[i] = c1 * exp(-(pow(x, 2.0) / c2));
+ s->weights[i] = c1 * exp(-x * x / c2);
total_weight += s->weights[i];
}