test-sum.c

/* Copyright 2018, Mansour Moufid <mansourmoufid@gmail.com> */

#undef NDEBUG

#include <assert.h>
#include <math.h>
#include <stdlib.h>

#include "nu.h"
#include "test.h"

static const float e = (float) M_E;
static const float pi = (float) M_PI;

int
main(void)
{
    float error;
    size_t n;
    float sum;
    float *z = NULL;

    error = 1e-5f;
    n = 1000;
    z = nu_array_alloc(n, sizeof(float));
    assert(z != NULL);
    z[0] = 1.f;
    float d = 1.f;
    for (size_t i = 1; i < n; i++) {
        d *= (float) i;
        z[i] = 1.f / d;
    }
    sum = nu_sum(z, n);
    assert(nu_eq(sum, e, error));
    free(z);

    struct nu_sum_state s;
    nu_sum_init(&s);
    n = 1000000;
    d = 1.f;
    float sgn = 1.f;
    nu_sum_add(&s, 1.f);
    for (size_t i = 1; i < n; i++) {
        sgn *= -1.f;
        d += 2.f;
        nu_sum_add(&s, sgn / d);
    }
    sum = 4.f * nu_sum_sum(&s);
    assert(nu_eq(sum, pi, error));

    error = 1e-6f;
    n = 1000;
    float *x;
    float *y;
    float dot;
    x = nu_array_alloc(n, sizeof(float));
    y = nu_array_alloc(n, sizeof(float));
    assert(x != NULL);
    assert(y != NULL);
    nu_array_linspace(x, 0.f, 1.f, n);
    for (size_t i = 0; i < n; i++) {
        y[i] = 0.f;
    }
    dot = nu_dot(x, y, n);
    assert(nu_eq(dot, 0.f, error));
    for (size_t i = 0; i < n; i++) {
        y[i] = 1.f;
    }
    sum = nu_sum(x, n);
    dot = nu_dot(x, y, n);
    assert(nu_eq(dot, sum, error));
    free(x);
    free(y);

    return 0;
}