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/* -*- mode: C -*- */
/*
IGraph library.
Copyright (C) 2011-2021 The igraph development team
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include <igraph.h>
#include "test_utilities.h"
void simple_tests(void) {
int i;
/* Seed the RNG, generate 10 random integers */
igraph_rng_seed(igraph_rng_default(), 42);
for (i = 0; i < 10; i++) {
printf("%" IGRAPH_PRId "\n", igraph_rng_get_integer(igraph_rng_default(), 10, 100));
}
printf("========\n");
/* Seed the RNG again with the same seed, verify that we get the same
* numbers */
igraph_rng_seed(igraph_rng_default(), 42);
for (i = 0; i < 10; i++) {
printf("%" IGRAPH_PRId "\n", igraph_rng_get_integer(igraph_rng_default(), 10, 100));
}
printf("========\n");
/* Seed the RNG again with a different seed, verify that we get different
* numbers */
igraph_rng_seed(igraph_rng_default(), 84);
for (i = 0; i < 10; i++) {
printf("%" IGRAPH_PRId "\n", igraph_rng_get_integer(igraph_rng_default(), 10, 100));
}
printf("========\n");
}
void generate_random_vector(
igraph_rng_t* rng, igraph_vector_int_t* numbers, igraph_integer_t lo, igraph_integer_t hi
) {
igraph_integer_t i, n = igraph_vector_int_size(numbers);
for (i = 0; i < n; i++) {
VECTOR(*numbers)[i] = igraph_rng_get_integer(rng, lo, hi);
}
IGRAPH_ASSERT(igraph_vector_int_min(numbers) >= lo);
IGRAPH_ASSERT(igraph_vector_int_max(numbers) <= hi);
}
/* Checks whether a given vector of numbers contains all numbers between `lo'
* and `hi' */
void check_occurrences(const igraph_vector_int_t* numbers, igraph_integer_t lo, igraph_integer_t hi) {
igraph_integer_t i;
for (i = lo; i <= hi; i++) {
IGRAPH_ASSERT(igraph_vector_int_contains(numbers, i));
}
}
/* Checks whether each X consecutive bits of the given numbers contain all
* possible combinations of (0, 1) as a quick proxy for randomness, for X = 1..4 */
void check_consecutive_bits(const igraph_vector_int_t* numbers, uint8_t num_bits) {
igraph_uint_t i, j, k, masked, n, mask, still_needed;
igraph_vector_bool_t seen;
n = igraph_vector_int_size(numbers);
for (j = 0; j < 4; j++) {
mask = ((igraph_integer_t) 1 << (j + 1)) - 1;
igraph_vector_bool_init(&seen, mask + 1);
for (i = 0; i < num_bits - j; i++, mask <<= 1) {
still_needed = (1 << (j + 1));
igraph_vector_bool_fill(&seen, 0);
for (k = 0; k < n; k++) {
masked = (VECTOR(*numbers)[k] & mask) >> i;
if (!VECTOR(seen)[masked]) {
VECTOR(seen)[masked] = 1;
still_needed--;
if (!still_needed) {
break;
}
}
}
if (still_needed) {
if (j > 0) {
printf(
"Expected %" IGRAPH_PRIu " consecutive bit(s) of random integers with "
"%d bits to contain all bit combinations.\n",
(j + 1), num_bits
);
printf(
"Missing %" IGRAPH_PRIu " combination(s) in bits %" IGRAPH_PRIu "-%" IGRAPH_PRIu "\n",
still_needed, (i + j), i
);
} else {
printf(
"Expected every bit of random integers with "
"%d bits to contain at least one 0 and at least one 1.\n",
num_bits
);
printf(
"This does not hold for bit %" IGRAPH_PRIu " in this vector:\n",
i
);
}
printf("\n");
print_vector_int(numbers);
IGRAPH_ASSERT(!still_needed);
}
}
igraph_vector_bool_destroy(&seen);
}
}
void stress_tests(void) {
igraph_rng_t rng;
const igraph_rng_type_t* rng_types[] = {
&igraph_rngtype_mt19937,
&igraph_rngtype_glibc2,
&igraph_rngtype_pcg32,
&igraph_rngtype_pcg64,
};
igraph_integer_t i;
igraph_vector_int_t numbers;
const igraph_integer_t N = 1000;
igraph_vector_int_init(&numbers, N);
for (i = 0; i < sizeof(rng_types) / sizeof(rng_types[0]); i++) {
igraph_error_handler_t *oldhandler = igraph_set_error_handler(&igraph_error_handler_printignore);
igraph_error_t err = igraph_rng_init(&rng, rng_types[i]);
switch (err) {
case IGRAPH_SUCCESS:
break;
case IGRAPH_UNIMPLEMENTED:
continue;
default:
IGRAPH_FATAL("Error while initializing RNG.");
}
igraph_set_error_handler(oldhandler);
igraph_rng_seed(&rng, 42);
/* We are going to test multiple ranges. In each range, we generate
* 1000 random numbers and test whether all the values are in the
* specified range. For the small ranges, we also test whether each
* value occurred at least once as the chances of this not happening is
* astronomically small */
/* Test integer generation in a small 0-based range */
generate_random_vector(&rng, &numbers, 0, 5);
check_occurrences(&numbers, 0, 5);
/* Test integer generation in a small non-0-based range */
generate_random_vector(&rng, &numbers, 8, 13);
check_occurrences(&numbers, 8, 13);
/* Test integer generation in a larger non-0-based range */
generate_random_vector(&rng, &numbers, -2048, 2047);
check_consecutive_bits(&numbers, 12);
/* Test integer generation in [0; IGRAPH_INTEGER_MAX] */
generate_random_vector(&rng, &numbers, 0, IGRAPH_INTEGER_MAX);
check_consecutive_bits(&numbers, sizeof(igraph_integer_t) * 8 - 1);
/* Test integer generation in [-5; IGRAPH_INTEGER_MAX-5] */
generate_random_vector(&rng, &numbers, -5, IGRAPH_INTEGER_MAX-5);
/* Test integer generation in [-5; IGRAPH_INTEGER_MAX] */
generate_random_vector(&rng, &numbers, -5, IGRAPH_INTEGER_MAX);
/* Test integer generation in [IGRAPH_INTEGER_MIN; -5] */
generate_random_vector(&rng, &numbers, IGRAPH_INTEGER_MIN, -5);
/* Test integer generation in [IGRAPH_INTEGER_MIN; IGRAPH_INTEGER_MAX] */
generate_random_vector(&rng, &numbers, IGRAPH_INTEGER_MIN, IGRAPH_INTEGER_MAX);
check_consecutive_bits(&numbers, sizeof(igraph_integer_t) * 8);
igraph_rng_destroy(&rng);
}
igraph_vector_int_destroy(&numbers);
}
int main(void) {
simple_tests();
stress_tests();
return 0;
}
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