forked from OSchip/llvm-project
329 lines
7.9 KiB
C
329 lines
7.9 KiB
C
/*
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* Copyright 2005-2007 Universiteit Leiden
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* Copyright 2008-2009 Katholieke Universiteit Leuven
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* Copyright 2010 INRIA Saclay
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*
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* Use of this software is governed by the MIT license
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*
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* Written by Sven Verdoolaege, Leiden Institute of Advanced Computer Science,
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* Universiteit Leiden, Niels Bohrweg 1, 2333 CA Leiden, The Netherlands
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* and K.U.Leuven, Departement Computerwetenschappen, Celestijnenlaan 200A,
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* B-3001 Leuven, Belgium
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* and INRIA Saclay - Ile-de-France, Parc Club Orsay Universite,
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* ZAC des vignes, 4 rue Jacques Monod, 91893 Orsay, France
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*/
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#include <isl_map_private.h>
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#include <isl_factorization.h>
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#include <isl_space_private.h>
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#include <isl_mat_private.h>
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static __isl_give isl_factorizer *isl_factorizer_alloc(
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__isl_take isl_morph *morph, int n_group)
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{
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isl_factorizer *f = NULL;
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int *len = NULL;
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if (!morph)
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return NULL;
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if (n_group > 0) {
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len = isl_alloc_array(morph->dom->ctx, int, n_group);
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if (!len)
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goto error;
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}
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f = isl_alloc_type(morph->dom->ctx, struct isl_factorizer);
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if (!f)
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goto error;
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f->morph = morph;
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f->n_group = n_group;
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f->len = len;
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return f;
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error:
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free(len);
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isl_morph_free(morph);
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return NULL;
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}
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void isl_factorizer_free(__isl_take isl_factorizer *f)
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{
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if (!f)
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return;
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isl_morph_free(f->morph);
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free(f->len);
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free(f);
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}
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void isl_factorizer_dump(__isl_take isl_factorizer *f)
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{
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int i;
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if (!f)
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return;
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isl_morph_print_internal(f->morph, stderr);
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fprintf(stderr, "[");
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for (i = 0; i < f->n_group; ++i) {
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if (i)
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fprintf(stderr, ", ");
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fprintf(stderr, "%d", f->len[i]);
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}
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fprintf(stderr, "]\n");
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}
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__isl_give isl_factorizer *isl_factorizer_identity(__isl_keep isl_basic_set *bset)
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{
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return isl_factorizer_alloc(isl_morph_identity(bset), 0);
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}
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__isl_give isl_factorizer *isl_factorizer_groups(__isl_keep isl_basic_set *bset,
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__isl_take isl_mat *Q, __isl_take isl_mat *U, int n, int *len)
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{
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int i;
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isl_size nvar;
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unsigned ovar;
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isl_space *space;
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isl_basic_set *dom;
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isl_basic_set *ran;
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isl_morph *morph;
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isl_factorizer *f;
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isl_mat *id;
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nvar = isl_basic_set_dim(bset, isl_dim_set);
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if (nvar < 0 || !Q || !U)
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goto error;
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ovar = 1 + isl_space_offset(bset->dim, isl_dim_set);
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id = isl_mat_identity(bset->ctx, ovar);
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Q = isl_mat_diagonal(isl_mat_copy(id), Q);
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U = isl_mat_diagonal(id, U);
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space = isl_basic_set_get_space(bset);
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dom = isl_basic_set_universe(isl_space_copy(space));
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space = isl_space_drop_dims(space, isl_dim_set, 0, nvar);
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space = isl_space_add_dims(space, isl_dim_set, nvar);
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ran = isl_basic_set_universe(space);
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morph = isl_morph_alloc(dom, ran, Q, U);
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f = isl_factorizer_alloc(morph, n);
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if (!f)
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return NULL;
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for (i = 0; i < n; ++i)
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f->len[i] = len[i];
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return f;
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error:
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isl_mat_free(Q);
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isl_mat_free(U);
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return NULL;
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}
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struct isl_factor_groups {
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int *pos; /* for each column: row position of pivot */
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int *group; /* group to which a column belongs */
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int *cnt; /* number of columns in the group */
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int *rowgroup; /* group to which a constraint belongs */
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};
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/* Initialize isl_factor_groups structure: find pivot row positions,
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* each column initially belongs to its own group and the groups
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* of the constraints are still unknown.
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*/
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static int init_groups(struct isl_factor_groups *g, __isl_keep isl_mat *H)
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{
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int i, j;
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if (!H)
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return -1;
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g->pos = isl_alloc_array(H->ctx, int, H->n_col);
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g->group = isl_alloc_array(H->ctx, int, H->n_col);
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g->cnt = isl_alloc_array(H->ctx, int, H->n_col);
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g->rowgroup = isl_alloc_array(H->ctx, int, H->n_row);
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if (!g->pos || !g->group || !g->cnt || !g->rowgroup)
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return -1;
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for (i = 0; i < H->n_row; ++i)
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g->rowgroup[i] = -1;
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for (i = 0, j = 0; i < H->n_col; ++i) {
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for ( ; j < H->n_row; ++j)
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if (!isl_int_is_zero(H->row[j][i]))
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break;
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g->pos[i] = j;
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}
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for (i = 0; i < H->n_col; ++i) {
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g->group[i] = i;
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g->cnt[i] = 1;
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}
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return 0;
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}
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/* Update group[k] to the group column k belongs to.
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* When merging two groups, only the group of the current
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* group leader is changed. Here we change the group of
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* the other members to also point to the group that the
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* old group leader now points to.
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*/
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static void update_group(struct isl_factor_groups *g, int k)
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{
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int p = g->group[k];
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while (g->cnt[p] == 0)
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p = g->group[p];
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g->group[k] = p;
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}
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/* Merge group i with all groups of the subsequent columns
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* with non-zero coefficients in row j of H.
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* (The previous columns are all zero; otherwise we would have handled
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* the row before.)
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*/
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static int update_group_i_with_row_j(struct isl_factor_groups *g, int i, int j,
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__isl_keep isl_mat *H)
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{
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int k;
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g->rowgroup[j] = g->group[i];
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for (k = i + 1; k < H->n_col && j >= g->pos[k]; ++k) {
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update_group(g, k);
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update_group(g, i);
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if (g->group[k] != g->group[i] &&
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!isl_int_is_zero(H->row[j][k])) {
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isl_assert(H->ctx, g->cnt[g->group[k]] != 0, return -1);
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isl_assert(H->ctx, g->cnt[g->group[i]] != 0, return -1);
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if (g->group[i] < g->group[k]) {
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g->cnt[g->group[i]] += g->cnt[g->group[k]];
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g->cnt[g->group[k]] = 0;
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g->group[g->group[k]] = g->group[i];
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} else {
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g->cnt[g->group[k]] += g->cnt[g->group[i]];
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g->cnt[g->group[i]] = 0;
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g->group[g->group[i]] = g->group[k];
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}
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}
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}
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return 0;
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}
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/* Update the group information based on the constraint matrix.
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*/
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static int update_groups(struct isl_factor_groups *g, __isl_keep isl_mat *H)
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{
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int i, j;
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for (i = 0; i < H->n_col && g->cnt[0] < H->n_col; ++i) {
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if (g->pos[i] == H->n_row)
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continue; /* A line direction */
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if (g->rowgroup[g->pos[i]] == -1)
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g->rowgroup[g->pos[i]] = i;
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for (j = g->pos[i] + 1; j < H->n_row; ++j) {
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if (isl_int_is_zero(H->row[j][i]))
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continue;
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if (g->rowgroup[j] != -1)
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continue;
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if (update_group_i_with_row_j(g, i, j, H) < 0)
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return -1;
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}
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}
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for (i = 1; i < H->n_col; ++i)
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update_group(g, i);
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return 0;
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}
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static void clear_groups(struct isl_factor_groups *g)
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{
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if (!g)
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return;
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free(g->pos);
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free(g->group);
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free(g->cnt);
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free(g->rowgroup);
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}
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/* Determine if the set variables of the basic set can be factorized and
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* return the results in an isl_factorizer.
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*
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* The algorithm works by first computing the Hermite normal form
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* and then grouping columns linked by one or more constraints together,
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* where a constraints "links" two or more columns if the constraint
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* has nonzero coefficients in the columns.
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*/
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__isl_give isl_factorizer *isl_basic_set_factorizer(
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__isl_keep isl_basic_set *bset)
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{
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int i, j, n, done;
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isl_mat *H, *U, *Q;
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isl_size nvar;
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struct isl_factor_groups g = { 0 };
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isl_factorizer *f;
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nvar = isl_basic_set_dim(bset, isl_dim_set);
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if (nvar < 0 || isl_basic_set_check_no_locals(bset) < 0)
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return NULL;
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if (nvar <= 1)
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return isl_factorizer_identity(bset);
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H = isl_mat_alloc(bset->ctx, bset->n_eq + bset->n_ineq, nvar);
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if (!H)
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return NULL;
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isl_mat_sub_copy(bset->ctx, H->row, bset->eq, bset->n_eq,
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0, 1 + isl_space_offset(bset->dim, isl_dim_set), nvar);
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isl_mat_sub_copy(bset->ctx, H->row + bset->n_eq, bset->ineq, bset->n_ineq,
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0, 1 + isl_space_offset(bset->dim, isl_dim_set), nvar);
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H = isl_mat_left_hermite(H, 0, &U, &Q);
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if (init_groups(&g, H) < 0)
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goto error;
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if (update_groups(&g, H) < 0)
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goto error;
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if (g.cnt[0] == nvar) {
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isl_mat_free(H);
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isl_mat_free(U);
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isl_mat_free(Q);
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clear_groups(&g);
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return isl_factorizer_identity(bset);
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}
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done = 0;
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n = 0;
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while (done != nvar) {
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int group = g.group[done];
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for (i = 1; i < g.cnt[group]; ++i) {
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if (g.group[done + i] == group)
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continue;
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for (j = done + g.cnt[group]; j < nvar; ++j)
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if (g.group[j] == group)
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break;
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if (j == nvar)
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isl_die(bset->ctx, isl_error_internal,
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"internal error", goto error);
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g.group[j] = g.group[done + i];
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Q = isl_mat_swap_rows(Q, done + i, j);
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U = isl_mat_swap_cols(U, done + i, j);
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}
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done += g.cnt[group];
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g.pos[n++] = g.cnt[group];
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}
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f = isl_factorizer_groups(bset, Q, U, n, g.pos);
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isl_mat_free(H);
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clear_groups(&g);
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return f;
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error:
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isl_mat_free(H);
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isl_mat_free(U);
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isl_mat_free(Q);
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clear_groups(&g);
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return NULL;
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}
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