2 * h3 := h1 intersect h2 */
| 313 | * h3 := h1 intersect h2 |
| 314 | */ |
| 315 | ideal idSect (ideal h1,ideal h2, GbVariant alg) |
| 316 | { |
| 317 | int i,j,k; |
| 318 | unsigned length; |
| 319 | int flength = id_RankFreeModule(h1,currRing); |
| 320 | int slength = id_RankFreeModule(h2,currRing); |
| 321 | int rank=si_max(h1->rank,h2->rank); |
| 322 | if ((idIs0(h1)) || (idIs0(h2))) return idInit(1,rank); |
| 323 | |
| 324 | BITSET save_opt; |
| 325 | SI_SAVE_OPT1(save_opt); |
| 326 | si_opt_1 |= Sy_bit(OPT_REDTAIL_SYZ); |
| 327 | |
| 328 | ideal first,second,temp,temp1,result; |
| 329 | poly p,q; |
| 330 | |
| 331 | if (IDELEMS(h1)<IDELEMS(h2)) |
| 332 | { |
| 333 | first = h1; |
| 334 | second = h2; |
| 335 | } |
| 336 | else |
| 337 | { |
| 338 | first = h2; |
| 339 | second = h1; |
| 340 | int t=flength; flength=slength; slength=t; |
| 341 | } |
| 342 | length = si_max(flength,slength); |
| 343 | if (length==0) |
| 344 | { |
| 345 | if ((currRing->qideal==NULL) |
| 346 | && (currRing->OrdSgn==1) |
| 347 | && (!rIsPluralRing(currRing)) |
| 348 | && ((TEST_V_INTERSECT_ELIM) || (!TEST_V_INTERSECT_SYZ))) |
| 349 | return idSectWithElim(first,second,alg); |
| 350 | else length = 1; |
| 351 | } |
| 352 | if (TEST_OPT_PROT) PrintS("intersect by syzygy methods\n"); |
| 353 | j = IDELEMS(first); |
| 354 | |
| 355 | ring orig_ring=currRing; |
| 356 | ring syz_ring=rAssure_SyzOrder(orig_ring,TRUE); |
| 357 | rSetSyzComp(length,syz_ring); |
| 358 | rChangeCurrRing(syz_ring); |
| 359 | |
| 360 | while ((j>0) && (first->m[j-1]==NULL)) j--; |
| 361 | temp = idInit(j /*IDELEMS(first)*/+IDELEMS(second),length+j); |
| 362 | k = 0; |
| 363 | for (i=0;i<j;i++) |
| 364 | { |
| 365 | if (first->m[i]!=NULL) |
| 366 | { |
| 367 | if (syz_ring==orig_ring) |
| 368 | temp->m[k] = pCopy(first->m[i]); |
| 369 | else |
| 370 | temp->m[k] = prCopyR(first->m[i], orig_ring, syz_ring); |
| 371 | q = pOne(); |
| 372 | pSetComp(q,i+1+length); |
no test coverage detected