basis_reduction_tab.c

   1 #include <assert.h>
   2 #include "isl_seq.h"
   3 #include "isl_tab.h"
   4
   5 struct tab_lp {
   6         struct isl_ctx  *ctx;
   7         struct isl_vec  *row;
   8         struct isl_tab  *tab;
   9         struct isl_tab_undo     **stack;
  10         isl_int         *obj;
  11         isl_int          opt;
  12         isl_int          opt_denom;
  13         int              neq;
  14         unsigned         dim;
  15         int              n_ineq;
  16 };
  17
  18 static struct tab_lp *init_lp(struct isl_basic_set *bset);
  19 static void set_lp_obj(struct tab_lp *lp, isl_int *row, int dim);
  20 static int solve_lp(struct tab_lp *lp);
  21 static void get_obj_val(struct tab_lp* lp, mpq_t *F);
  22 static void delete_lp(struct tab_lp *lp);
  23 static int add_lp_row(struct tab_lp *lp, isl_int *row, int dim);
  24 static void get_alpha(struct tab_lp* lp, int row, mpq_t *alpha);
  25 static void del_lp_row(struct tab_lp *lp);
  26
  27 #define GBR_LP                              struct tab_lp
  28 #define GBR_type                            mpq_t
  29 #define GBR_init(v)                         mpq_init(v)
  30 #define GBR_clear(v)                        mpq_clear(v)
  31 #define GBR_set(a,b)                        mpq_set(a,b)
  32 #define GBR_set_ui(a,b)                     mpq_set_ui(a,b,1)
  33 #define GBR_mul(a,b,c)                      mpq_mul(a,b,c)
  34 #define GBR_lt(a,b)                         (mpq_cmp(a,b) < 0)
  35 #define GBR_floor(a,b)                      mpz_fdiv_q(a,mpq_numref(b),mpq_denref(b))
  36 #define GBR_ceil(a,b)                       mpz_cdiv_q(a,mpq_numref(b),mpq_denref(b))
  37 #define GBR_lp_init(P)                      init_lp(P)
  38 #define GBR_lp_set_obj(lp, obj, dim)        set_lp_obj(lp, obj, dim)
  39 #define GBR_lp_solve(lp)                    solve_lp(lp)
  40 #define GBR_lp_get_obj_val(lp, F)           get_obj_val(lp, F)
  41 #define GBR_lp_delete(lp)                   delete_lp(lp)
  42 #define GBR_lp_next_row(lp)                 lp->neq
  43 #define GBR_lp_add_row(lp, row, dim)        add_lp_row(lp, row, dim)
  44 #define GBR_lp_get_alpha(lp, row, alpha)    get_alpha(lp, row, alpha)
  45 #define GBR_lp_del_row(lp)                  del_lp_row(lp);
  46 #include "basis_reduction_templ.c"
  47
  48 /* Set up a tableau for the Cartesian product of bset with itself.
  49  * This could be optimized by first setting up a tableau for bset
  50  * and then performing the Cartesian product on the tableau.
  51  */
  52 static struct isl_tab *gbr_tab(struct isl_basic_set *bset,
  53         struct isl_vec *row)
  54 {
  55         int i, j;
  56         unsigned dim;
  57         struct isl_tab *tab;
  58
  59         if (!bset || !row)
  60                 return NULL;
  61
  62         dim = isl_basic_set_total_dim(bset);
  63         tab = isl_tab_alloc(bset->ctx, 2 * bset->n_ineq + dim + 1, 2 * dim, 0);
  64
  65         for (i = 0; i < 2; ++i) {
  66                 isl_seq_clr(row->el + 1 + (1 - i) * dim, dim);
  67                 for (j = 0; j < bset->n_ineq; ++j) {
  68                         isl_int_set(row->el[0], bset->ineq[j][0]);
  69                         isl_seq_cpy(row->el + 1 + i * dim,
  70                                     bset->ineq[j] + 1, dim);
  71                         tab = isl_tab_add_ineq(tab, row->el);
  72                         if (!tab || tab->empty)
  73                                 return tab;
  74                 }
  75         }
  76
  77         return tab;
  78 }
  79
  80 static struct tab_lp *init_lp(struct isl_basic_set *bset)
  81 {
  82         struct tab_lp *lp = NULL;
  83
  84         if (!bset)
  85                 return NULL;
  86
  87         isl_assert(bset->ctx, bset->n_eq == 0, return NULL);
  88
  89         lp = isl_calloc_type(bset->ctx, struct tab_lp);
  90         if (!lp)
  91                 return NULL;
  92
  93         isl_int_init(lp->opt);
  94         isl_int_init(lp->opt_denom);
  95
  96         lp->dim = isl_basic_set_total_dim(bset);
  97         lp->n_ineq = bset->n_ineq;
  98
  99         lp->ctx = bset->ctx;
 100         isl_ctx_ref(lp->ctx);
 101
 102         lp->stack = isl_alloc_array(lp->ctx, struct isl_tab_undo *, lp->dim);
 103
 104         lp->row = isl_vec_alloc(lp->ctx, 1 + 2 * lp->dim);
 105         if (!lp->row)
 106                 goto error;
 107         lp->tab = gbr_tab(bset, lp->row);
 108         if (!lp->tab)
 109                 goto error;
 110         lp->obj = NULL;
 111         lp->neq = 0;
 112
 113         return lp;
 114 error:
 115         delete_lp(lp);
 116         return NULL;
 117 }
 118
 119 static void set_lp_obj(struct tab_lp *lp, isl_int *row, int dim)
 120 {
 121         lp->obj = row;
 122 }
 123
 124 static int solve_lp(struct tab_lp *lp)
 125 {
 126         enum isl_lp_result res;
 127         unsigned flags = 0;
 128
 129         isl_int_set_si(lp->row->el[0], 0);
 130         isl_seq_cpy(lp->row->el + 1, lp->obj, lp->dim);
 131         isl_seq_neg(lp->row->el + 1 + lp->dim, lp->obj, lp->dim);
 132         if (lp->neq)
 133                 flags = ISL_TAB_SAVE_DUAL;
 134         res = isl_tab_min(lp->tab, lp->row->el, lp->ctx->one,
 135                           &lp->opt, &lp->opt_denom, flags);
 136         if (res != isl_lp_ok)
 137                 return -1;
 138         return 0;
 139 }
 140
 141 static void get_obj_val(struct tab_lp* lp, mpq_t *F)
 142 {
 143         isl_int_neg(mpq_numref(*F), lp->opt);
 144         isl_int_set(mpq_denref(*F), lp->opt_denom);
 145 }
 146
 147 static void delete_lp(struct tab_lp *lp)
 148 {
 149         if (!lp)
 150                 return;
 151
 152         isl_int_clear(lp->opt);
 153         isl_int_clear(lp->opt_denom);
 154         isl_vec_free(lp->row);
 155         free(lp->stack);
 156         isl_tab_free(lp->tab);
 157         isl_ctx_deref(lp->ctx);
 158         free(lp);
 159 }
 160
 161 static int add_lp_row(struct tab_lp *lp, isl_int *row, int dim)
 162 {
 163         lp->stack[lp->neq] = isl_tab_snap(lp->tab);
 164
 165         isl_int_set_si(lp->row->el[0], 0);
 166         isl_seq_cpy(lp->row->el + 1, row, lp->dim);
 167         isl_seq_neg(lp->row->el + 1 + lp->dim, row, lp->dim);
 168
 169         lp->tab = isl_tab_add_valid_eq(lp->tab, lp->row->el);
 170
 171         return lp->neq++;
 172 }
 173
 174 static void get_alpha(struct tab_lp* lp, int row, mpq_t *alpha)
 175 {
 176         row += 2 * lp->n_ineq;
 177         isl_int_neg(mpq_numref(*alpha), lp->tab->dual->el[1 + row]);
 178         isl_int_set(mpq_denref(*alpha), lp->tab->dual->el[0]);
 179 }
 180
 181 static void del_lp_row(struct tab_lp *lp)
 182 {
 183         lp->neq--;
 184         isl_tab_rollback(lp->tab, lp->stack[lp->neq]);
 185 }