add isl_set_max

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>

diff --git a/doc/user.pod b/doc/user.pod
index d03bf54..bec4f9d 100644 (file)
--- a/doc/user.pod
+++ b/doc/user.pod
@@ -1533,6 +1533,17 @@ that contains the whole input set or relation.
 In case of union sets and relations, the polyhedral hull is computed
 per space.
 
+=item * Optimization
+
+       #include <isl/ilp.h>
+       enum isl_lp_result isl_set_max(__isl_keep isl_set *set,
+               __isl_keep isl_aff *obj, isl_int *opt);
+
+Compute the maximum of the integer affine expression C<obj>
+over the points in C<set>, returning the result in C<opt>.
+The return value may be one of C<isl_lp_error>,
+C<isl_lp_ok>, C<isl_lp_unbounded> or C<isl_lp_empty>.
+
 =item * Dual
 
 The following functions compute either the set of (rational) coefficient

diff --git a/include/isl/ilp.h b/include/isl/ilp.h
index f7db311..9d19543 100644 (file)
--- a/include/isl/ilp.h
+++ b/include/isl/ilp.h
@@ -10,6 +10,7 @@
 #ifndef ISL_ILP_H
 #define ISL_ILP_H
 
+#include <isl/aff.h>
 #include <isl/lp.h>
 
 #if defined(__cplusplus)
@@ -19,6 +20,8 @@ extern "C" {
 enum isl_lp_result isl_basic_set_solve_ilp(struct isl_basic_set *bset, int max,
                                      isl_int *f, isl_int *opt,
                                      struct isl_vec **sol_p);
+enum isl_lp_result isl_set_max(__isl_keep isl_set *set,
+       __isl_keep isl_aff *obj, isl_int *opt);
 
 #if defined(__cplusplus)
 }

diff --git a/isl_ilp.c b/isl_ilp.c
index 8c8d8fc..ec0fe30 100644 (file)
--- a/isl_ilp.c
+++ b/isl_ilp.c
@@ -13,6 +13,9 @@
 #include "isl_sample.h"
 #include <isl/seq.h>
 #include "isl_equalities.h"
+#include <isl_aff_private.h>
+#include <isl_local_space_private.h>
+#include <isl_mat_private.h>
 
 /* Given a basic set "bset", construct a basic set U such that for
  * each element x in U, the whole unit box positioned at x is inside
@@ -331,3 +334,140 @@ error:
        isl_basic_set_free(bset);
        return isl_lp_error;
 }
+
+static enum isl_lp_result basic_set_opt(__isl_keep isl_basic_set *bset, int max,
+       __isl_keep isl_aff *obj, isl_int *opt)
+{
+       enum isl_lp_result res;
+
+       if (!obj)
+               return isl_lp_error;
+       bset = isl_basic_set_copy(bset);
+       bset = isl_basic_set_underlying_set(bset);
+       res = isl_basic_set_solve_ilp(bset, max, obj->v->el + 1, opt, NULL);
+       isl_basic_set_free(bset);
+       return res;
+}
+
+static __isl_give isl_mat *extract_divs(__isl_keep isl_basic_set *bset)
+{
+       int i;
+       isl_ctx *ctx = isl_basic_set_get_ctx(bset);
+       isl_mat *div;
+
+       div = isl_mat_alloc(ctx, bset->n_div,
+                           1 + 1 + isl_basic_set_total_dim(bset));
+       if (!div)
+               return NULL;
+
+       for (i = 0; i < bset->n_div; ++i)
+               isl_seq_cpy(div->row[i], bset->div[i], div->n_col);
+
+       return div;
+}
+
+enum isl_lp_result isl_basic_set_opt(__isl_keep isl_basic_set *bset, int max,
+       __isl_keep isl_aff *obj, isl_int *opt)
+{
+       int *exp1 = NULL;
+       int *exp2 = NULL;
+       isl_ctx *ctx;
+       isl_mat *bset_div = NULL;
+       isl_mat *div = NULL;
+       enum isl_lp_result res;
+
+       if (!bset || !obj)
+               return isl_lp_error;
+
+       ctx = isl_aff_get_ctx(obj);
+       if (!isl_dim_equal(bset->dim, obj->ls->dim))
+               isl_die(ctx, isl_error_invalid,
+                       "spaces don't match", return isl_lp_error);
+       if (!isl_int_is_one(obj->v->el[0]))
+               isl_die(ctx, isl_error_unsupported,
+                       "expecting integer affine expression",
+                       return isl_lp_error);
+
+       if (bset->n_div == 0 && obj->ls->div->n_row == 0)
+               return basic_set_opt(bset, max, obj, opt);
+
+       bset = isl_basic_set_copy(bset);
+       obj = isl_aff_copy(obj);
+
+       bset_div = extract_divs(bset);
+       exp1 = isl_alloc_array(ctx, int, bset_div->n_row);
+       exp2 = isl_alloc_array(ctx, int, obj->ls->div->n_row);
+       if (!bset_div || !exp1 || !exp2)
+               goto error;
+
+       div = isl_merge_divs(bset_div, obj->ls->div, exp1, exp2);
+
+       bset = isl_basic_set_expand_divs(bset, isl_mat_copy(div), exp1);
+       obj = isl_aff_expand_divs(obj, isl_mat_copy(div), exp2);
+
+       res = basic_set_opt(bset, max, obj, opt);
+
+       isl_mat_free(bset_div);
+       isl_mat_free(div);
+       free(exp1);
+       free(exp2);
+       isl_basic_set_free(bset);
+       isl_aff_free(obj);
+
+       return res;
+error:
+       isl_mat_free(div);
+       isl_mat_free(bset_div);
+       free(exp1);
+       free(exp2);
+       isl_basic_set_free(bset);
+       isl_aff_free(obj);
+       return isl_lp_error;
+}
+
+/* Compute the minimum (maximum if max is set) of the integer affine
+ * expression obj over the points in set and put the result in *opt.
+ */
+enum isl_lp_result isl_set_opt(__isl_keep isl_set *set, int max,
+       __isl_keep isl_aff *obj, isl_int *opt)
+{
+       int i;
+       enum isl_lp_result res;
+       int empty = 1;
+       isl_int opt_i;
+
+       if (!set || !obj)
+               return isl_lp_error;
+       if (set->n == 0)
+               return isl_lp_empty;
+
+       res = isl_basic_set_opt(set->p[0], max, obj, opt);
+       if (res == isl_lp_error || res == isl_lp_unbounded)
+               return res;
+       if (set->n == 1)
+               return res;
+       if (res == isl_lp_ok)
+               empty = 0;
+
+       isl_int_init(opt_i);
+       for (i = 1; i < set->n; ++i) {
+               res = isl_basic_set_opt(set->p[i], max, obj, &opt_i);
+               if (res == isl_lp_error || res == isl_lp_unbounded) {
+                       isl_int_clear(opt_i);
+                       return res;
+               }
+               if (res == isl_lp_ok)
+                       empty = 0;
+               if (isl_int_gt(opt_i, *opt))
+                       isl_int_set(*opt, opt_i);
+       }
+       isl_int_clear(opt_i);
+
+       return empty ? isl_lp_empty : isl_lp_ok;
+}
+
+enum isl_lp_result isl_set_max(__isl_keep isl_set *set,
+       __isl_keep isl_aff *obj, isl_int *opt)
+{
+       return isl_set_opt(set, 1, obj, opt);
+}