computeVectorB

void computeVectorB(int n, double *A, double *b) {
    for (int i = 0; i < n; ++i) {
        b[i] = 0.0;
        for (int k = 0; k <= (n + 1) / 2; k++) {
            int j = 2 * k;
            if (j < n) {
                b[i] += A[i * n + j];
            }
        }
    }
}