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Remove parameter perm_inv. perm_inv overcomplex the process for gener… #29

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Remove parameter perm_inv. perm_inv overcomplex the process for gener… #29

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74 changes: 12 additions & 62 deletions permutation.c
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Original file line number Diff line number Diff line change
Expand Up @@ -145,7 +145,6 @@ void *generate_chase(const struct generate_chase_common_args *args,
perm_t *tlb_perm;
perm_t *perm;
size_t i;
perm_t *perm_inverse;
size_t mixer_scale = stride / nr_mixer_indices;

if (verbosity > 1)
Expand All @@ -162,28 +161,16 @@ void *generate_chase(const struct generate_chase_common_args *args,

dassert(is_a_permutation(perm, nr_elts));

if (verbosity > 1) printf("generating inverse permtuation\n");
perm_inverse = malloc(nr_elts * sizeof(*perm));
for (i = 0; i < nr_elts; ++i) {
perm_inverse[perm[i]] = i;
}

dassert(is_a_permutation(perm_inverse, nr_elts));

#define MIXED(x) ((x)*stride + mixer[(x) & (args->nr_mixers - 1)] * mixer_scale)

if (verbosity > 1)
printf("threading the chase (mixer_idx = %zu)\n", mixer_idx);
for (i = 0; i < nr_elts; ++i) {
size_t next;
dassert(perm[perm_inverse[i]] == i);
next = perm_inverse[i] + 1;
next = (next == nr_elts) ? 0 : next;
*(void **)(arena + MIXED(i)) = (void *)(arena + MIXED(perm[next]));
size_t next = (i+1 == nr_elts) ? 0 : i+1;
*(void **)(arena + MIXED(perm[i])) = (void *)(arena + MIXED(perm[next]));
}

free(perm);
free(perm_inverse);

return arena + MIXED(0);
}
Expand All @@ -210,7 +197,6 @@ void *generate_chase_long(const struct generate_chase_common_args *args,
size_t i;
size_t j;
size_t base;
perm_t *perm_inverse;
size_t mixer_scale = stride / nr_mixer_indices;

if (verbosity > 1)
Expand Down Expand Up @@ -244,60 +230,24 @@ void *generate_chase_long(const struct generate_chase_common_args *args,
free(tlb_perm);

dassert(is_a_permutation(perm, nr_elts));
if (verbosity > 1)
printf("generating inverse permutation\n");
}

dassert(is_a_permutation(perm, nr_iteration * nr_elts));

perm_inverse = malloc(nr_iteration * nr_elts * sizeof(*perm_inverse));
if (perm_inverse == NULL) {
fprintf(stderr, "Could not allocate %lu bytes\n",
nr_iteration * nr_elts * sizeof(*perm_inverse));
exit(1);
}

for (i = 0; i < nr_iteration * nr_elts; ++i) {
perm_inverse[perm[i]] = i;
}

dassert(is_a_permutation(perm_inverse, nr_iteration, nr_elts));

// Get the [(x mod NR_MIXER)th element in the jth row of mixer]th element
// in the xth stride of the array.
#define MIXED_2(x,j,n) ((x)*stride + (mixer + j*n)[(x) & (n-1)] * mixer_scale)

if (verbosity > 1)
printf("threading the chase (mixer_idx = %zu)\n", mixer_idx);
#define MIXED_2(x,i) ((x)*stride + mixer[i*args->nr_mixers + ((x) & (args->nr_mixers-1))] * mixer_scale)

// Generate the final permutation, which connects nr_iteration * nr_elts
// number of permutations together into one.
for (i = 0; i < nr_elts * nr_iteration; ++i) {
size_t next;
dassert(perm[perm_inverse[i]] == i);
assert(*(void **)(arena + MIXED_2(i%nr_elts,i/nr_elts, args->nr_mixers)) == NULL);
next = perm_inverse[i] + 1;
// If next is the position representing the start of a new iteration of
// permutation, set next to be the position representing the start of
// current iteration, because we want to finish current permutation before
// proceeding to the next.
next = (next%nr_elts == 0 && next/nr_elts > i/nr_elts) ? i/nr_elts*nr_elts : next;

if (perm[next]%nr_elts == 0) {
// If current iteration of permutation is finished,
// new position is the start of next iteration.
size_t new = (i/nr_elts + 1) * nr_elts;
new = (new == nr_iteration * nr_elts) ? 0 : new;
*(void **)(arena + MIXED_2(i%nr_elts,i/nr_elts, args->nr_mixers)) =
(void *)(arena + MIXED_2(new%nr_elts,new/nr_elts, args->nr_mixers));
} else {
*(void **)(arena + MIXED_2(i%nr_elts,i/nr_elts, args->nr_mixers)) =
(void *)(arena + MIXED_2(perm[next]%nr_elts,perm[next]/nr_elts, args->nr_mixers));
size_t cur = 0;
for (i = 0; i < nr_iteration; ++i) {
for (j = 0; j < nr_elts; ++j) {
size_t next = cur+1 == nr_iteration * nr_elts? 0: cur+1;
size_t i_next = j+1==nr_elts? (next==0? 0: i+1): i;
*(void **)(arena + MIXED_2(perm[cur]%nr_elts,i)) =
(void *)(arena + MIXED_2(perm[next]%nr_elts,i_next));
cur++;
}
}

free(perm);
free(perm_inverse);

return arena + MIXED_2(0,0, args->nr_mixers);
return arena + MIXED_2(0,0);
}