48 lines
1.4 KiB
C
48 lines
1.4 KiB
C
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#ifndef RANDOMINUS_H
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#define RANDOMINUS_H
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/* To randomize an array - hopefully as fast as possible */
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#include "fastrand/fastrand.h"
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/** swap */
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static void inline rd_swap(uint32_t *a, uint32_t *b) {
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uint32_t tmp = *a;
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*a = *b;
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*b = tmp;
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}
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/** This is by no means "cryptographically correct" or stuff, but fast */
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static inline void randominus(uint32_t *a, int n, uint32_t seed) {
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/** Initialized ILP random generator */
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uint32_t ilp_seeds[8];
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rand_ilp_state rsi;
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rand_state rs = init_rand();
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for(int i = 0; i < 8; ++i) {
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uint32_t choice = rand_between(&rs, 0, n);
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ilp_seeds[i] = choice;
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}
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/** Go over the array and randomly swap stuff - hand unrolled with ILP random get! */
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for(int i = 0; i < (n - 8); i += 8) {
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uint32_t to0 = fastmodlike(lcg_ilp(&rsi, A), n);
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uint32_t to1 = fastmodlike(lcg_ilp(&rsi, B), n);
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uint32_t to2 = fastmodlike(lcg_ilp(&rsi, C), n);
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uint32_t to3 = fastmodlike(lcg_ilp(&rsi, D), n);
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uint32_t to4 = fastmodlike(lcg_ilp(&rsi, E), n);
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uint32_t to5 = fastmodlike(lcg_ilp(&rsi, F), n);
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uint32_t to6 = fastmodlike(lcg_ilp(&rsi, G), n);
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uint32_t to7 = fastmodlike(lcg_ilp(&rsi, H), n);
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rd_swap(&a[i], &a[to0]);
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rd_swap(&a[i + 1], &a[to1]);
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rd_swap(&a[i + 2], &a[to2]);
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rd_swap(&a[i + 3], &a[to3]);
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rd_swap(&a[i + 4], &a[to4]);
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rd_swap(&a[i + 5], &a[to5]);
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rd_swap(&a[i + 6], &a[to6]);
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rd_swap(&a[i + 7], &a[to7]);
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}
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}
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#endif /* RANDOMINUS_H */
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