2 #include "isl_basis_reduction.h"
3 #include "isl_equalities.h"
7 /* The input of this program is the same as that of the "polytope_scan"
8 * program from the barvinok distribution.
10 * Constraints of set is PolyLib format.
12 * The input set is assumed to be bounded.
15 static struct isl_mat *isl_basic_set_samples(struct isl_basic_set *bset);
17 static struct isl_mat *samples_eq(struct isl_basic_set *bset)
20 struct isl_mat *samples;
22 bset = isl_basic_set_remove_equalities(bset, &T, NULL);
23 samples = isl_basic_set_samples(bset);
24 return isl_mat_product(samples, isl_mat_transpose(T));
27 /* Add the current sample value of the tableau "tab" to the list
30 static struct isl_mat *add_solution(struct isl_mat *samples,
33 struct isl_vec *sample;
37 samples = isl_mat_extend(samples, samples->n_row + 1, samples->n_col);
40 sample = isl_tab_get_sample_value(tab);
43 isl_seq_cpy(samples->row[samples->n_row - 1], sample->el, sample->size);
47 isl_mat_free(samples);
51 /* Look for and return all integer points in "bset", which is assumed
54 * We first compute a reduced basis for the set and then scan
55 * the set in the directions of this basis.
56 * We basically perform a depth first search, where in each level i
57 * we compute the range in the i-th basis vector direction, given
58 * fixed values in the directions of the previous basis vector.
59 * We then add an equality to the tableau fixing the value in the
60 * direction of the current basis vector to each value in the range
61 * in turn and then continue to the next level.
63 * The search is implemented iteratively. "level" identifies the current
64 * basis vector. "init" is true if we want the first value at the current
65 * level and false if we want the next value.
66 * Solutions are added in the leaves of the search tree, i.e., after
67 * we have fixed a value in each direction of the basis.
69 static struct isl_mat *isl_basic_set_samples(struct isl_basic_set *bset)
72 struct isl_mat *B = NULL;
73 struct isl_tab *tab = NULL;
76 struct isl_mat *samples;
77 struct isl_tab_undo **snap;
80 enum isl_lp_result res;
83 return samples_eq(bset);
85 dim = isl_basic_set_total_dim(bset);
87 min = isl_vec_alloc(bset->ctx, dim);
88 max = isl_vec_alloc(bset->ctx, dim);
89 samples = isl_mat_alloc(bset->ctx, 0, 1 + dim);
90 snap = isl_alloc_array(bset->ctx, struct isl_tab_undo *, dim);
92 if (!min || !max || !samples || !snap)
96 B = isl_basic_set_reduced_basis(bset);
98 B = isl_mat_identity(bset->ctx, dim);
99 B = isl_mat_lin_to_aff(B);
103 tab = isl_tab_from_basic_set(bset);
111 res = isl_tab_min(tab, B->row[1 + level],
112 bset->ctx->one, &min->el[level], NULL, 0);
113 if (res == isl_lp_empty)
115 if (res == isl_lp_error || res == isl_lp_unbounded)
117 isl_seq_neg(B->row[1 + level] + 1,
118 B->row[1 + level] + 1, dim);
119 res = isl_tab_min(tab, B->row[1 + level],
120 bset->ctx->one, &max->el[level], NULL, 0);
121 isl_seq_neg(B->row[1 + level] + 1,
122 B->row[1 + level] + 1, dim);
123 isl_int_neg(max->el[level], max->el[level]);
124 if (res == isl_lp_empty)
126 if (res == isl_lp_error || res == isl_lp_unbounded)
128 snap[level] = isl_tab_snap(tab);
130 isl_int_add_ui(min->el[level], min->el[level], 1);
132 if (empty || isl_int_gt(min->el[level], max->el[level])) {
136 isl_tab_rollback(tab, snap[level]);
139 isl_int_neg(B->row[1 + level][0], min->el[level]);
140 tab = isl_tab_add_valid_eq(tab, B->row[1 + level]);
141 isl_int_set_si(B->row[1 + level][0], 0);
142 if (level < dim - 1) {
147 samples = add_solution(samples, tab);
149 isl_tab_rollback(tab, snap[level]);
156 isl_basic_set_free(bset);
162 isl_mat_free(samples);
165 isl_basic_set_free(bset);
170 int main(int argc, char **argv)
172 struct isl_ctx *ctx = isl_ctx_alloc();
173 struct isl_basic_set *bset;
174 struct isl_mat *samples;
176 bset = isl_basic_set_read_from_file(ctx, stdin, 0, ISL_FORMAT_POLYLIB);
177 samples = isl_basic_set_samples(bset);
178 isl_mat_dump(samples, stdout, 0);
179 isl_mat_free(samples);