enum lp_result PL_polyhedron_opt(Polyhedron *P, Value *obj, Value denom,
enum lp_dir dir, Value *opt)
{
int i;
int first = 1;
Value val, d;
enum lp_result res = lp_empty;
POL_ENSURE_VERTICES(P);
if (emptyQ(P))
return res;
value_init(val);
value_init(d);
for (i = 0; i < P->NbRays; ++ i) {
Inner_Product(P->Ray[i]+1, obj, P->Dimension+1, &val);
if (value_zero_p(P->Ray[i][0]) && value_notzero_p(val)) {
res = lp_unbounded;
break;
}
if (value_zero_p(P->Ray[i][1+P->Dimension])) {
if ((dir == lp_min && value_neg_p(val)) ||
(dir == lp_max && value_pos_p(val))) {
res = lp_unbounded;
break;
}
} else {
res = lp_ok;
value_multiply(d, denom, P->Ray[i][1+P->Dimension]);
if (dir == lp_min)
mpz_cdiv_q(val, val, d);
else
mpz_fdiv_q(val, val, d);
if (first || (dir == lp_min ? value_lt(val, *opt) :
value_gt(val, *opt)))
value_assign(*opt, val);
first = 0;
}
}
value_clear(d);
value_clear(val);
return res;
}
/**
* Tests Constraints_fullDimensionize by comparing the Ehrhart polynomials
* @param A the input set of constraints
* @param B the corresponding context
* @param the number of samples to generate for the test
* @return 1 if the Ehrhart polynomial had the same value for the
* full-dimensional and non-full-dimensional sets of constraints, for their
* corresponding sample parameters values.
*/
int test_Constraints_fullDimensionize(Matrix * A, Matrix * B,
unsigned int nbSamples) {
Matrix * Eqs= NULL, *ParmEqs=NULL, *VL=NULL;
unsigned int * elimVars=NULL, * elimParms=NULL;
Matrix * sample, * smallerSample=NULL;
Matrix * transfSample=NULL;
Matrix * parmVL=NULL;
unsigned int i, j, r, nbOrigParms, nbParms;
Value div, mod, *origVal=NULL, *fullVal=NULL;
Matrix * VLInv;
Polyhedron * P, *PC;
Matrix * M, *C;
Enumeration * origEP, * fullEP=NULL;
const char **fullNames = NULL;
int isOk = 1; /* holds the result */
/* compute the origial Ehrhart polynomial */
M = Matrix_Copy(A);
C = Matrix_Copy(B);
P = Constraints2Polyhedron(M, maxRays);
PC = Constraints2Polyhedron(C, maxRays);
origEP = Polyhedron_Enumerate(P, PC, maxRays, origNames);
Matrix_Free(M);
Matrix_Free(C);
Polyhedron_Free(P);
Polyhedron_Free(PC);
/* compute the full-dimensional polyhedron corresponding to A and its Ehrhart
polynomial */
M = Matrix_Copy(A);
C = Matrix_Copy(B);
nbOrigParms = B->NbColumns-2;
Constraints_fullDimensionize(&M, &C, &VL, &Eqs, &ParmEqs,
&elimVars, &elimParms, maxRays);
if ((Eqs->NbRows==0) && (ParmEqs->NbRows==0)) {
Matrix_Free(M);
Matrix_Free(C);
Matrix_Free(Eqs);
Matrix_Free(ParmEqs);
free(elimVars);
free(elimParms);
return 1;
}
nbParms = C->NbColumns-2;
P = Constraints2Polyhedron(M, maxRays);
PC = Constraints2Polyhedron(C, maxRays);
namesWithoutElim(origNames, nbOrigParms, elimParms, &fullNames);
fullEP = Polyhedron_Enumerate(P, PC, maxRays, fullNames);
Matrix_Free(M);
Matrix_Free(C);
Polyhedron_Free(P);
Polyhedron_Free(PC);
/* make a set of sample parameter values and compare the corresponding
Ehrhart polnomials */
sample = Matrix_Alloc(1,nbOrigParms);
transfSample = Matrix_Alloc(1, nbParms);
Lattice_extractSubLattice(VL, nbParms, &parmVL);
VLInv = Matrix_Alloc(parmVL->NbRows, parmVL->NbRows+1);
MatInverse(parmVL, VLInv);
if (dbg) {
show_matrix(parmVL);
show_matrix(VLInv);
}
srand(nbSamples);
value_init(mod);
value_init(div);
for (i = 0; i< nbSamples; i++) {
/* create a random sample */
for (j=0; j< nbOrigParms; j++) {
value_set_si(sample->p[0][j], rand()%100);
}
/* compute the corresponding value for the full-dimensional
constraints */
valuesWithoutElim(sample, elimParms, &smallerSample);
/* (N' i' 1)^T = VLinv.(N i 1)^T*/
for (r = 0; r < nbParms; r++) {
Inner_Product(&(VLInv->p[r][0]), smallerSample->p[0], nbParms,
&(transfSample->p[0][r]));
/* add the constant part */
value_addto(transfSample->p[0][r], transfSample->p[0][r],
VLInv->p[r][VLInv->NbColumns-2]);
value_pdivision(div, transfSample->p[0][r],
VLInv->p[r][VLInv->NbColumns-1]);
value_subtract(mod, transfSample->p[0][r], div);
/* if the parameters value does not belong to the validity lattice, the
Ehrhart polynomial is zero. */
if (!value_zero_p(mod)) {
fullEP = Enumeration_zero(nbParms, maxRays);
break;
}
}
/* compare the two forms of the Ehrhart polynomial.*/
if (origEP ==NULL) break; /* NULL has loose semantics for EPs */
origVal = compute_poly(origEP, sample->p[0]);
fullVal = compute_poly(fullEP, transfSample->p[0]);
if (!value_eq(*origVal, *fullVal)) {
isOk = 0;
printf("EPs don't match. \n Original value = ");
value_print(stdout, VALUE_FMT, *origVal);
printf("\n Original sample = [");
for (j=0; j<sample->NbColumns; j++) {
value_print(stdout, VALUE_FMT, sample->p[0][j]);
printf(" ");
}
printf("] \n EP = ");
if(origEP!=NULL) {
print_evalue(stdout, &(origEP->EP), origNames);
}
else {
printf("NULL");
}
printf(" \n Full-dimensional value = ");
value_print(stdout, P_VALUE_FMT, *fullVal);
printf("\n full-dimensional sample = [");
for (j=0; j<sample->NbColumns; j++) {
value_print(stdout, VALUE_FMT, transfSample->p[0][j]);
printf(" ");
}
printf("] \n EP = ");
if(origEP!=NULL) {
print_evalue(stdout, &(origEP->EP), fullNames);
}
else {
printf("NULL");
}
}
if (dbg) {
printf("\nOriginal value = ");
value_print(stdout, VALUE_FMT, *origVal);
printf("\nFull-dimensional value = ");
value_print(stdout, P_VALUE_FMT, *fullVal);
printf("\n");
}
value_clear(*origVal);
value_clear(*fullVal);
}
value_clear(mod);
value_clear(div);
Matrix_Free(sample);
Matrix_Free(smallerSample);
Matrix_Free(transfSample);
Enumeration_Free(origEP);
Enumeration_Free(fullEP);
return isOk;
} /* test_Constraints_fullDimensionize */
