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Annotation of OpenXM_contrib2/asir2000/engine/Hgfs.c, Revision 1.35

1.35    ! noro        1: /* $OpenXM: OpenXM_contrib2/asir2000/engine/Hgfs.c,v 1.34 2018/03/29 01:32:51 noro Exp $ */
1.1       noro        2:
                      3: #include "ca.h"
1.22      noro        4: #include "inline.h"
1.1       noro        5:
1.30      noro        6: int debug_sfbfctr;
                      7:
1.18      noro        8: void lnfsf(int n,UM p0,UM p1,struct p_pair *list,UM np0,UM np1);
1.20      noro        9: void extractcoefbm(BM f,int dx,UM r);
1.35    ! noro       10: void sqfrsf(VL vl, P f, DCP *dcp);
1.1       noro       11:
1.18      noro       12: int comp_dum(DUM a,DUM b)
1.12      noro       13: {
1.34      noro       14:   if ( DEG(a->f) > DEG(b->f) )
                     15:     return -1;
                     16:   else if ( DEG(a->f) < DEG(b->f) )
                     17:     return 1;
                     18:   else
                     19:     return 0;
1.12      noro       20: }
                     21:
1.25      noro       22: void ufctrsf(P p,DCP *dcp)
1.1       noro       23: {
1.34      noro       24:   int n,i,j,k;
                     25:   DCP dc,dc0;
                     26:   P lc;
                     27:   UM mp;
                     28:   UM *tl;
                     29:   Obj obj;
                     30:   struct oDUM *udc,*udc1;
                     31:
                     32:   simp_ff((Obj)p,&obj); p = (P)obj;
                     33:   if ( !p ) {
                     34:     NEWDC(dc); COEF(dc) = 0; DEG(dc) = ONE;
                     35:     NEXT(dc) = 0; *dcp = dc;
                     36:     return;
                     37:   }
                     38:   mp = W_UMALLOC(UDEG(p));
                     39:   ptosfum(p,mp);
                     40:   if ( (n = DEG(mp)) < 0 ) {
                     41:     *dcp = 0; return;
                     42:   } else if ( n == 0 ) {
                     43:     NEWDC(dc); COEF(dc) = p; DEG(dc) = ONE;
                     44:     NEXT(dc) = 0; *dcp = dc;
                     45:     return;
                     46:   }
                     47:   lc = COEF(DC(p));
                     48:   if ( !_isonesf(COEF(mp)[n]) ) {
                     49:     monicsfum(mp);
                     50:   }
                     51:
                     52:   W_CALLOC(n+1,struct oDUM,udc);
                     53:   gensqfrsfum(mp,udc);
                     54:
                     55:   tl = (UM *)ALLOCA((n+1)*sizeof(UM));
                     56:   W_CALLOC(DEG(mp)+1,struct oDUM,udc1);
                     57:
                     58:   for ( i = 0,j = 0; udc[i].f; i++ )
                     59:     if ( DEG(udc[i].f) == 1 ) {
                     60:       udc1[j].f = udc[i].f; udc1[j].n = udc[i].n; j++;
                     61:     } else {
                     62:       bzero((char *)tl,(n+1)*sizeof(UM));
                     63:       czsfum(udc[i].f,tl);
                     64:       for ( k = 0; tl[k]; k++, j++ ) {
                     65:         udc1[j].f = tl[k]; udc1[j].n = udc[i].n;
                     66:       }
                     67:     }
                     68:   udc = udc1;
                     69:   for ( i = 0; udc[i].f; i++ );
                     70:   qsort(udc,i,sizeof(struct oDUM),
                     71:     (int (*)(const void *,const void *))comp_dum);
                     72:
                     73:   NEWDC(dc0); COEF(dc0) = lc; DEG(dc0) = ONE; dc = dc0;
                     74:   for ( n = 0; udc[n].f; n++ ) {
                     75:     NEWDC(NEXT(dc)); dc = NEXT(dc);
                     76:     STOQ(udc[n].n,DEG(dc)); sfumtop(VR(p),udc[n].f,&COEF(dc));
                     77:   }
                     78:   NEXT(dc) = 0; *dcp = dc0;
1.1       noro       79: }
                     80:
1.18      noro       81: void gensqfrsfum(UM p,struct oDUM *dc)
1.1       noro       82: {
1.34      noro       83:   int n,i,j,d,mod;
                     84:   UM t,s,g,f,f1,b;
                     85:   GFS u,v;
                     86:
                     87:   if ( (n = DEG(p)) == 1 ) {
                     88:     dc[0].f = UMALLOC(DEG(p)); cpyum(p,dc[0].f); dc[0].n = 1;
                     89:     return;
                     90:   }
                     91:   t = W_UMALLOC(n); s = W_UMALLOC(n); g = W_UMALLOC(n);
                     92:   f = W_UMALLOC(n); f1 = W_UMALLOC(n); b = W_UMALLOC(n);
                     93:   diffsfum(p,t); cpyum(p,s); gcdsfum(t,s,g);
                     94:   if ( !DEG(g) ) {
                     95:     dc[0].f = UMALLOC(DEG(p)); cpyum(p,dc[0].f); dc[0].n = 1;
                     96:     return;
                     97:   }
                     98:   cpyum(p,b); cpyum(p,t); divsfum(t,g,f);
                     99:   for ( i = 0, d = 0; DEG(f); i++ ) {
                    100:     while ( 1 ) {
                    101:       cpyum(b,t);
                    102:       if ( divsfum(t,f,s) >= 0 )
                    103:         break;
                    104:       else {
                    105:         cpyum(s,b); d++;
                    106:       }
                    107:     }
                    108:     cpyum(b,t); cpyum(f,s); gcdsfum(t,s,f1);
                    109:     divsfum(f,f1,s); cpyum(f1,f);
                    110:     dc[i].f = UMALLOC(DEG(s)); cpyum(s,dc[i].f); dc[i].n = d;
                    111:   }
                    112:   mod = characteristic_sf();
                    113:   if ( DEG(b) > 0 ) {
                    114:     d = 1;
                    115:     while ( 1 ) {
                    116:       cpyum(b,t);
                    117:       for ( j = DEG(t); j >= 0; j-- )
                    118:         if ( COEF(t)[j] && (j % mod) )
                    119:           break;
                    120:       if ( j >= 0 )
                    121:         break;
                    122:       else {
                    123:         DEG(s) = DEG(t)/mod;
                    124:         for ( j = 0; j <= DEG(t); j++ ) {
                    125:           iftogfs(COEF(t)[j*mod],&u);
                    126:           pthrootgfs(u,&v);
                    127:           COEF(s)[j] = v?FTOIF(CONT(v)):0;
                    128:         }
                    129:         cpyum(s,b); d *= mod;
                    130:       }
                    131:     }
                    132:     gensqfrsfum(b,dc+i);
                    133:     for ( j = i; dc[j].f; j++ )
                    134:       dc[j].n *= d;
                    135:   }
1.1       noro      136: }
                    137:
1.18      noro      138: void randsfum(int d,UM p)
1.1       noro      139: {
1.34      noro      140:   int i;
1.1       noro      141:
1.34      noro      142:   for ( i = 0; i < d; i++ )
                    143:     COEF(p)[i] = _randomsf();
                    144:   for ( i = d-1; i >= 0 && !COEF(p)[i]; i-- );
                    145:   p->d = i;
1.1       noro      146: }
                    147:
1.18      noro      148: void pwrmodsfum(UM p,int e,UM f,UM pr)
1.1       noro      149: {
1.34      noro      150:   UM wt,ws,q;
1.1       noro      151:
1.34      noro      152:   if ( e == 0 ) {
                    153:     DEG(pr) = 0; COEF(pr)[0] = _onesf();
                    154:   } else if ( DEG(p) < 0 )
                    155:     DEG(pr) = -1;
                    156:   else if ( e == 1 ) {
                    157:     q = W_UMALLOC(DEG(p)); cpyum(p,pr);
                    158:     DEG(pr) = divsfum(pr,f,q);
                    159:   } else if ( DEG(p) == 0 ) {
                    160:     DEG(pr) = 0; COEF(pr)[0] = _pwrsf(COEF(p)[0],e);
                    161:   } else {
                    162:     wt = W_UMALLOC(2*DEG(f)); ws = W_UMALLOC(2*DEG(f));
                    163:     q = W_UMALLOC(2*DEG(f));
                    164:     pwrmodsfum(p,e/2,f,wt);
                    165:     if ( !(e%2) )  {
                    166:       mulsfum(wt,wt,pr); DEG(pr) = divsfum(pr,f,q);
                    167:     } else {
                    168:       mulsfum(wt,wt,ws);
                    169:       DEG(ws) = divsfum(ws,f,q);
                    170:       mulsfum(ws,p,pr);
                    171:       DEG(pr) = divsfum(pr,f,q);
                    172:     }
                    173:   }
1.1       noro      174: }
                    175:
1.18      noro      176: void spwrsfum(UM m,UM f,N e,UM r)
1.1       noro      177: {
1.34      noro      178:   UM t,s,q;
                    179:   N e1;
                    180:   int a;
                    181:
                    182:   if ( !e ) {
                    183:     DEG(r) = 0; COEF(r)[0] = _onesf();
                    184:   } else if ( UNIN(e) )
                    185:     cpyum(f,r);
                    186:   else {
                    187:     a = divin(e,2,&e1);
                    188:     t = W_UMALLOC(2*DEG(m)); spwrsfum(m,f,e1,t);
                    189:     s = W_UMALLOC(2*DEG(m)); q = W_UMALLOC(2*DEG(m));
                    190:     mulsfum(t,t,s); DEG(s) = divsfum(s,m,q);
                    191:     if ( a ) {
                    192:       mulsfum(s,f,t); DEG(t) = divsfum(t,m,q); cpyum(t,r);
1.1       noro      193:         } else
1.34      noro      194:       cpyum(s,r);
                    195:   }
1.1       noro      196: }
                    197:
1.18      noro      198: void tracemodsfum(UM m,UM f,int e,UM r)
1.2       noro      199: {
1.34      noro      200:   UM t,s,q,u;
                    201:   int i;
1.2       noro      202:
1.34      noro      203:   q = W_UMALLOC(2*DEG(m)+DEG(f)); /* XXX */
                    204:   t = W_UMALLOC(2*DEG(m));
                    205:   s = W_UMALLOC(2*DEG(m));
                    206:   u = W_UMALLOC(2*DEG(m));
                    207:   DEG(f) = divsfum(f,m,q);
                    208:   cpyum(f,s);
                    209:   cpyum(f,t);
                    210:   for ( i = 1; i < e; i++ ) {
                    211:     mulsfum(t,t,u);
                    212:     DEG(u) = divsfum(u,m,q); cpyum(u,t);
                    213:     addsfum(t,s,u); cpyum(u,s);
                    214:   }
                    215:   cpyum(s,r);
1.2       noro      216: }
                    217:
1.18      noro      218: void make_qmatsf(UM p,UM *tab,int ***mp)
1.1       noro      219: {
1.34      noro      220:   int n,i,j;
                    221:   int *c;
                    222:   UM q,r;
                    223:   int **mat;
                    224:   int one;
                    225:
                    226:   n = DEG(p);
                    227:   *mp = mat = almat(n,n);
                    228:   for ( j = 0; j < n; j++ ) {
                    229:     r = W_UMALLOC(DEG(tab[j])); q = W_UMALLOC(DEG(tab[j]));
                    230:     cpyum(tab[j],r); DEG(r) = divsfum(r,p,q);
                    231:     for ( i = 0, c = COEF(r); i <= DEG(r); i++ )
                    232:       mat[i][j] = c[i];
                    233:   }
                    234:   one = _onesf();
                    235:   for ( i = 0; i < n; i++ )
                    236:     mat[i][i] = _subsf(mat[i][i],one);
1.1       noro      237: }
                    238:
1.18      noro      239: void nullsf(int **mat,int n,int *ind)
1.1       noro      240: {
1.34      noro      241:   int i,j,l,s,h,inv;
                    242:   int *t,*u;
1.1       noro      243:
1.34      noro      244:   bzero((char *)ind,n*sizeof(int));
                    245:   ind[0] = 0;
                    246:   for ( i = j = 0; j < n; i++, j++ ) {
                    247:     for ( ; j < n; j++ ) {
                    248:       for ( l = i; l < n; l++ )
                    249:         if ( mat[l][j] )
                    250:           break;
                    251:       if ( l < n ) {
                    252:         t = mat[i]; mat[i] = mat[l]; mat[l] = t; break;
                    253:       } else
                    254:         ind[j] = 1;
                    255:     }
                    256:     if ( j == n )
                    257:       break;
                    258:     inv = _invsf(mat[i][j]);
                    259:     for ( s = j, t = mat[i]; s < n; s++ )
                    260:       t[s] = _mulsf(t[s],inv);
                    261:     for ( l = 0; l < n; l++ ) {
                    262:       if ( l == i )
                    263:         continue;
                    264:       u = mat[l]; h = _chsgnsf(u[j]);
                    265:       for ( s = j; s < n; s++ )
                    266:         u[s] = _addsf(_mulsf(h,t[s]),u[s]);
                    267:     }
                    268:   }
1.1       noro      269: }
                    270:
1.18      noro      271: void null_to_solsf(int **mat,int *ind,int n,UM *r)
1.1       noro      272: {
1.34      noro      273:   int i,j,k,l;
                    274:   int *c;
                    275:   UM w;
                    276:
                    277:   for ( i = 0, l = 0; i < n; i++ ) {
                    278:     if ( !ind[i] )
                    279:       continue;
                    280:     w = UMALLOC(n);
                    281:     for ( j = k = 0, c = COEF(w); j < n; j++ )
                    282:       if ( ind[j] )
                    283:         c[j] = 0;
                    284:       else
                    285:         c[j] = mat[k++][i];
                    286:     c[i] = _chsgnsf(_onesf());
                    287:     for ( j = n; j >= 0; j-- )
                    288:       if ( c[j] )
                    289:         break;
                    290:     DEG(w) = j;
                    291:     r[l++] = w;
                    292:   }
1.1       noro      293: }
                    294: /*
                    295: make_qmatsf(p,tab,mp)
                    296: nullsf(mat,n,ind)
                    297: null_to_solsf(ind,n,r)
                    298: */
                    299:
1.18      noro      300: void czsfum(UM f,UM *r)
1.1       noro      301: {
1.34      noro      302:   int i,j;
                    303:   int d,n,ord;
                    304:   UM s,t,u,v,w,g,x,m,q;
                    305:   UM *base;
                    306:
                    307:   n = DEG(f); base = (UM *)ALLOCA(n*sizeof(UM));
                    308:   bzero((char *)base,n*sizeof(UM));
                    309:
                    310:   w = W_UMALLOC(2*n); q = W_UMALLOC(2*n); m = W_UMALLOC(2*n);
                    311:
                    312:   base[0] = W_UMALLOC(0); DEG(base[0]) = 0; COEF(base[0])[0] = _onesf();
                    313:
                    314:   t = W_UMALLOC(1); DEG(t) = 1; COEF(t)[0] = 0; COEF(t)[1] = _onesf();
                    315:
                    316:   ord = field_order_sf();
                    317:   pwrmodsfum(t,ord,f,w);
                    318:   base[1] = W_UMALLOC(DEG(w));
                    319:   cpyum(w,base[1]);
                    320:
                    321:   for ( i = 2; i < n; i++ ) {
                    322:     mulsfum(base[i-1],base[1],m);
                    323:     DEG(m) = divsfum(m,f,q);
                    324:     base[i] = W_UMALLOC(DEG(m)); cpyum(m,base[i]);
                    325:   }
                    326:
                    327:   v = W_UMALLOC(n); cpyum(f,v);
                    328:   DEG(w) = 1; COEF(w)[0] = 0; COEF(w)[1] = _onesf();
                    329:   x = W_UMALLOC(1); DEG(x) = 1; COEF(x)[0] = 0; COEF(x)[1] = _onesf();
                    330:   t = W_UMALLOC(n); s = W_UMALLOC(n); u = W_UMALLOC(n); g = W_UMALLOC(n);
                    331:
                    332:   for ( j = 0, d = 1; 2*d <= DEG(v); d++ ) {
                    333:     for ( DEG(t) = -1, i = 0; i <= DEG(w); i++ )
                    334:       if ( COEF(w)[i] ) {
                    335:         mulssfum(base[i],COEF(w)[i],s);
                    336:         addsfum(s,t,u); cpyum(u,t);
                    337:       }
                    338:     cpyum(t,w); cpyum(v,s); subsfum(w,x,t);
                    339:     gcdsfum(s,t,g);
                    340:     if ( DEG(g) >= 1 ) {
                    341:       berlekampsf(g,d,base,r+j); j += DEG(g)/d;
                    342:       divsfum(v,g,q); cpyum(q,v);
                    343:       DEG(w) = divsfum(w,v,q);
                    344:       for ( i = 0; i < DEG(v); i++ )
                    345:         DEG(base[i]) = divsfum(base[i],v,q);
                    346:     }
                    347:   }
                    348:   if ( DEG(v) ) {
                    349:     r[j] = UMALLOC(DEG(v)); cpyum(v,r[j]); j++;
                    350:   }
                    351:   r[j] = 0;
1.1       noro      352: }
                    353:
1.18      noro      354: int berlekampsf(UM p,int df,UM *tab,UM *r)
1.1       noro      355: {
1.34      noro      356:   int n,i,j,k,nf,d,nr;
                    357:   int **mat;
                    358:   int *ind;
                    359:   UM mp,w,q,gcd,w1,w2;
                    360:   UM *u;
                    361:   int *root;
                    362:
                    363:   n = DEG(p);
                    364:   ind = ALLOCA(n*sizeof(int));
                    365:   make_qmatsf(p,tab,&mat);
                    366:   nullsf(mat,n,ind);
                    367:   for ( i = 0, d = 0; i < n; i++ )
                    368:     if ( ind[i] )
                    369:       d++;
                    370:   if ( d == 1 ) {
                    371:     r[0] = UMALLOC(n); cpyum(p,r[0]); return 1;
                    372:   }
                    373:   u = ALLOCA(d*sizeof(UM *));
                    374:   r[0] = UMALLOC(n); cpyum(p,r[0]);
                    375:   null_to_solsf(mat,ind,n,u);
                    376:   root = ALLOCA(d*sizeof(int));
                    377:   w = W_UMALLOC(n); mp = W_UMALLOC(d);
                    378:   w1 = W_UMALLOC(n); w2 = W_UMALLOC(n);
                    379:   for ( i = 1, nf = 1; i < d; i++ ) {
                    380:     minipolysf(u[i],p,mp);
                    381:     nr = find_rootsf(mp,root);
                    382:     for ( j = 0; j < nf; j++ ) {
                    383:       if ( DEG(r[j]) == df )
                    384:         continue;
                    385:       for ( k = 0; k < nr; k++ ) {
                    386:         cpyum(u[i],w1); cpyum(r[j],w2);
                    387:         COEF(w1)[0] = _chsgnsf(root[k]);
                    388:         gcdsfum(w1,w2,w);
                    389:         if ( DEG(w) > 0 && DEG(w) < DEG(r[j]) ) {
                    390:           gcd = UMALLOC(DEG(w));
                    391:           q = UMALLOC(DEG(r[j])-DEG(w));
                    392:           cpyum(w,gcd); divsfum(r[j],w,q);
                    393:           r[j] = q; r[nf++] = gcd;
                    394:         }
                    395:         if ( nf == d )
                    396:           return d;
                    397:       }
                    398:     }
                    399:   }
                    400:   /* NOT REACHED */
                    401:   error("berlekampsf : cannot happen");
                    402:   return 0;
1.1       noro      403: }
                    404:
1.18      noro      405: void minipolysf(UM f,UM p,UM mp)
1.1       noro      406: {
1.34      noro      407:   struct p_pair *list,*l,*l1,*lprev;
                    408:   int n,d;
                    409:   UM u,p0,p1,np0,np1,q,w;
                    410:
                    411:   list = (struct p_pair *)MALLOC(sizeof(struct p_pair));
                    412:   list->p0 = u = W_UMALLOC(0); DEG(u) = 0; COEF(u)[0] = _onesf();
                    413:   list->p1 = W_UMALLOC(0); cpyum(list->p0,list->p1);
                    414:   list->next = 0;
                    415:   n = DEG(p); w = UMALLOC(2*n);
                    416:   p0 = UMALLOC(2*n); cpyum(list->p0,p0);
                    417:   p1 = UMALLOC(2*n); cpyum(list->p1,p1);
                    418:   q = W_UMALLOC(2*n);
                    419:   while ( 1 ) {
                    420:     COEF(p0)[DEG(p0)] = 0; DEG(p0)++; COEF(p0)[DEG(p0)] = _onesf();
                    421:     mulsfum(f,p1,w); DEG(w) = divsfum(w,p,q); cpyum(w,p1);
                    422:     np0 = UMALLOC(n); np1 = UMALLOC(n);
                    423:     lnfsf(n,p0,p1,list,np0,np1);
                    424:     if ( DEG(np1) < 0 ) {
                    425:       cpyum(np0,mp); return;
                    426:     } else {
                    427:       l1 = (struct p_pair *)MALLOC(sizeof(struct p_pair));
                    428:       l1->p0 = np0; l1->p1 = np1;
                    429:       for ( l = list, lprev = 0, d = DEG(np1);
                    430:         l && (DEG(l->p1) > d); lprev = l, l = l->next );
                    431:       if ( lprev ) {
                    432:         lprev->next = l1; l1->next = l;
                    433:       } else {
                    434:         l1->next = list; list = l1;
                    435:       }
                    436:     }
                    437:   }
1.1       noro      438: }
                    439:
1.18      noro      440: void lnfsf(int n,UM p0,UM p1,struct p_pair *list,UM np0,UM np1)
1.1       noro      441: {
1.34      noro      442:   int h,d1;
                    443:   UM t0,t1,s0,s1;
                    444:   struct p_pair *l;
                    445:
                    446:   cpyum(p0,np0); cpyum(p1,np1);
                    447:   t0 = W_UMALLOC(n); t1 = W_UMALLOC(n);
                    448:   s0 = W_UMALLOC(n); s1 = W_UMALLOC(n);
                    449:   for ( l = list; l; l = l->next ) {
                    450:     d1 = DEG(np1);
                    451:     if ( d1 == DEG(l->p1) ) {
                    452:       h = _divsf(COEF(np1)[d1],_chsgnsf(COEF(l->p1)[d1]));
                    453:       mulssfum(l->p0,h,t0); addsfum(np0,t0,s0); cpyum(s0,np0);
                    454:       mulssfum(l->p1,h,t1); addsfum(np1,t1,s1); cpyum(s1,np1);
                    455:     }
                    456:   }
1.1       noro      457: }
                    458:
1.18      noro      459: int find_rootsf(UM p,int *root)
1.1       noro      460: {
1.34      noro      461:   UM *r;
                    462:   int i,n;
1.1       noro      463:
1.34      noro      464:   n = DEG(p);
                    465:   r = ALLOCA((DEG(p))*sizeof(UM));
                    466:   canzassf(p,1,r);
                    467:   for ( i = 0; i < n; i++ )
                    468:     root[i] = _chsgnsf(COEF(r[i])[0]);
                    469:   return n;
1.1       noro      470: }
                    471:
1.18      noro      472: void canzassf(UM f,int d,UM *r)
1.1       noro      473: {
1.34      noro      474:   UM t,s,u,w,g,o;
                    475:   N n1,n2,n3,n4,n5;
                    476:   UM *b;
                    477:   int n,q,ed;
                    478:
                    479:   if ( DEG(f) == d ) {
                    480:     r[0] = UMALLOC(d); cpyum(f,r[0]);
                    481:     return;
                    482:   } else {
                    483:     n = DEG(f); b = (UM *)ALLOCA(n*sizeof(UM));
                    484:     bzero((char *)b,n*sizeof(UM));
                    485:
                    486:     t = W_UMALLOC(2*d);
                    487:     s = W_UMALLOC(DEG(f)); u = W_UMALLOC(DEG(f));
                    488:     w = W_UMALLOC(DEG(f)); g = W_UMALLOC(DEG(f));
                    489:     o = W_UMALLOC(0); DEG(o) = 0; COEF(o)[0] = _onesf();
                    490:     q = field_order_sf();
                    491:     if ( q % 2 ) {
                    492:       STON(q,n1); pwrn(n1,d,&n2); subn(n2,ONEN,&n3);
                    493:       STON(2,n4); divsn(n3,n4,&n5);
                    494:     } else
                    495:       ed = d*extdeg_sf();
                    496:     while ( 1 ) {
                    497:       randsfum(2*d,t);
                    498:       if ( q % 2 ) {
                    499:         spwrsfum(f,t,n5,s); subsfum(s,o,u);
                    500:       } else
                    501:         tracemodsfum(f,t,ed,u);
                    502:       cpyum(f,w);
                    503:       gcdsfum(w,u,g);
                    504:       if ( (DEG(g) >= 1) && (DEG(g) < DEG(f)) ) {
                    505:         canzassf(g,d,r);
                    506:         cpyum(f,w); divsfum(w,g,s);
                    507:         canzassf(s,d,r+DEG(g)/d);
                    508:         return;
                    509:       }
                    510:     }
                    511:   }
1.1       noro      512: }
                    513:
1.3       noro      514: /* Hensel related functions */
                    515:
1.28      noro      516: int sfberle(V,V,P,int,GFS *,DCP *);
1.3       noro      517: void sfgcdgen(P,ML,ML *);
1.5       noro      518: void sfhenmain2(BM,UM,UM,int,BM *);
                    519: void ptosfbm(int,P,BM);
1.28      noro      520: void sfhensel(int count,P f,V x,V y,int degbound,GFS *evp,P *sfp,ML *listp);
1.3       noro      521:
                    522: /* f = f(x,y) */
                    523:
1.28      noro      524: void sfhensel(int count,P f,V x,V y,int degbound,GFS *evp,P *sfp,ML *listp)
1.3       noro      525: {
1.34      noro      526:   int i;
                    527:   int fn;
                    528:   ML rlist;
                    529:   BM fl;
                    530:   VL vl,nvl;
                    531:   int dx,dy,bound;
                    532:   GFS ev;
                    533:   P f1,t,c,sf;
                    534:   DCP dc,dct,dc0;
                    535:   UM q,fm,hm;
                    536:   UM *gm;
                    537:   struct oEGT tmp0,tmp1,eg_hensel,eg_hensel_t;
                    538:
                    539:   clctv(CO,f,&vl);
                    540:   if ( vl->v != x ) {
                    541:     reordvar(vl,x,&nvl); reorderp(nvl,vl,f,&f1);
                    542:     vl = nvl; f = f1;
                    543:   }
                    544:   if ( vl->next )
                    545:     y = vl->next->v;
                    546:   dx = getdeg(x,f);
                    547:   dy = getdeg(y,f);
                    548:   if ( dx == 1 ) {
                    549:     *listp = rlist = MLALLOC(1); rlist->n = 1; rlist->c[0] = 0;
                    550:     return;
                    551:   }
                    552:   fn = sfberle(x,y,f,count,&ev,&dc);
                    553:   if ( fn <= 1 ) {
                    554:     /* fn == 0 => short of evaluation points */
                    555:     *listp = rlist = MLALLOC(1); rlist->n = fn; rlist->c[0] = 0;
                    556:     return;
                    557:   }
                    558:   if ( degbound >= 0 ) {
                    559:     /*
                    560:      * reconstruct dc so that
                    561:      * dc[1],... : factors satisfy degree bound
                    562:      * dc[0]     : product of others
                    563:      */
                    564:     c = dc->c; dc = NEXT(dc);
                    565:     dc0 = 0;
                    566:     fn = 0;
                    567:     while ( dc ) {
                    568:       if ( getdeg(x,COEF(dc)) <= degbound ) {
                    569:         dct = NEXT(dc); NEXT(dc) = dc0; dc0 = dc; dc = dct;
                    570:         fn++;
                    571:       } else {
                    572:         mulp(vl,COEF(dc),c,&t); c = t;
                    573:         dc = NEXT(dc);
                    574:       }
                    575:     }
                    576:     if ( OID(c) == O_P ) {
                    577:       NEWDC(dc); COEF(dc) = c; DEG(dc) = ONE; NEXT(dc) = dc0;
                    578:       fn++;
                    579:     } else {
                    580:       mulp(vl,dc0->c,c,&t); dc0->c = t; dc = dc0;
                    581:     }
                    582:   } else {
                    583:     /* pass the the leading coeff. to the first element */
                    584:     c = dc->c; dc = NEXT(dc);
                    585:     mulp(vl,dc->c,c,&t); dc->c = t;
                    586:   }
                    587:
                    588:   /* convert mod y-a factors into UM */
                    589:   gm = (UM *)ALLOCA(fn*sizeof(UM));
                    590:   for ( i = 0; i < fn; i++, dc = NEXT(dc) ) {
                    591:     gm[i] = W_UMALLOC(UDEG(dc->c));
                    592:     ptosfum(dc->c,gm[i]);
                    593:   }
                    594:
                    595:   /* set bound */
                    596:   /* g | f, lc_y(g) = lc_y(f) => deg_y(g) <= deg_y(f) */
                    597:   /* so, bound = dy is sufficient, but we use slightly large value */
                    598:   bound = dy+2;
                    599:
                    600:   /* f(x,y) -> f(x,y+ev) */
                    601:   fl = BMALLOC(dx,bound);
                    602:   ptosfbm(bound,f,fl);
                    603:   if ( ev ) shiftsfbm(fl,FTOIF(CONT(ev)));
                    604:
                    605:   /* sf = f(x+ev) */
                    606:   sfbmtop(fl,x,y,&sf);
                    607:
                    608:   /* fm = fl mod y */
                    609:   fm = W_UMALLOC(dx);
                    610:   cpyum(COEF(fl)[0],fm);
                    611:   hm = W_UMALLOC(dx);
                    612:
                    613:   q = W_UMALLOC(dx);
                    614:   rlist = MLALLOC(fn); rlist->n = fn; rlist->bound = bound;
                    615:   if ( debug_sfbfctr )
                    616:     fprintf(asir_out,"%d candidates\n",fn);
                    617:   init_eg(&eg_hensel);
                    618:   for ( i = 0; i < fn-1; i++ ) {
                    619:     if ( debug_sfbfctr )
                    620:       fprintf(asir_out,"deg(fm) = %d, deg(gm[%d]) = %d\n",
                    621:       DEG(fm),i,DEG(gm[i]));
                    622:     init_eg(&eg_hensel_t);
                    623:     get_eg(&tmp0);
                    624:     /* fl = gm[i]*hm mod y */
                    625:     divsfum(fm,gm[i],hm);
                    626:     /* fl is replaced by the cofactor of gk mod y^bound */
                    627:     /* rlist->c[i] = gk */
                    628:     sfhenmain2(fl,gm[i],hm,bound,(BM *)&rlist->c[i]);
                    629:     cpyum(hm,fm);
                    630:     get_eg(&tmp1); add_eg(&eg_hensel_t,&tmp0,&tmp1);
                    631:     add_eg(&eg_hensel,&tmp0,&tmp1);
                    632:     if ( debug_sfbfctr) {
                    633:       print_eg("Hensel",&eg_hensel_t);
                    634:       fprintf(asir_out,"\n");
                    635:     }
                    636:   }
                    637:   if ( debug_sfbfctr) {
                    638:     print_eg("Hensel total",&eg_hensel);
                    639:     fprintf(asir_out,"\n");
                    640:   }
                    641:   /* finally, fl must be the lift of gm[fn-1] */
                    642:   rlist->c[i] = fl;
1.4       noro      643:
1.8       noro      644: #if 0
1.34      noro      645:   /* y -> y-a */
                    646:   mev = _chsgnsf(FTOIF(CONT(ev)));
                    647:   for ( i = 0; i < fn; i++ )
                    648:     shiftsfbm((BM)(rlist->c[i]),mev);
1.8       noro      649: #endif
1.34      noro      650:   *evp = ev;
                    651:   *sfp = sf;
                    652:   *listp = rlist;
1.3       noro      653: }
                    654:
                    655: /* main variable of f = x */
                    656:
1.28      noro      657: int sfberle(V x,V y,P f,int count,GFS *ev,DCP *dcp)
1.3       noro      658: {
1.34      noro      659:   UM wf,wf1,wf2,wfs,gcd;
                    660:   int fn,n;
                    661:   GFS m,fm;
                    662:   DCP dc,dct,dc0;
                    663:   VL vl;
                    664:   P lc,lc0,f0;
                    665:   Obj obj;
                    666:   int j,q,index,i;
                    667:
                    668:   NEWVL(vl); vl->v = x;
                    669:   NEWVL(NEXT(vl)); NEXT(vl)->v = y;
                    670:   NEXT(NEXT(vl)) =0;
                    671:   simp_ff((Obj)f,&obj); f = (P)obj;
                    672:   n = QTOS(DEG(DC(f)));
                    673:   wf = W_UMALLOC(n); wf1 = W_UMALLOC(n); wf2 = W_UMALLOC(n);
                    674:   wfs = W_UMALLOC(n); gcd = W_UMALLOC(n);
                    675:   q = field_order_sf();
                    676:   lc = DC(f)->c;
                    677:   for ( j = 0, fn = n + 1, index = 0;
                    678:     index < q && j < count && fn > 1; index++ ) {
                    679:     indextogfs(index,&m);
                    680:     substp(vl,lc,y,(P)m,&lc0);
                    681:     if ( lc0 ) {
                    682:       substp(vl,f,y,(P)m,&f0);
                    683:       ptosfum(f0,wf); cpyum(wf,wf1);
                    684:       diffsfum(wf1,wf2); gcdsfum(wf1,wf2,gcd);
                    685:       if ( DEG(gcd) == 0 ) {
                    686:         ufctrsf(f0,&dc);
                    687:         for ( dct = NEXT(dc), i = 0; dct; dct = NEXT(dct), i++ );
                    688:         if ( i < fn ) {
                    689:           dc0 = dc; fn = i; fm = m;
                    690:         }
                    691:         j++;
                    692:       }
                    693:     }
                    694:   }
                    695:   if ( index == q )
                    696:     return 0;
                    697:   else if ( fn == 1 )
                    698:     return 1;
                    699:   else {
                    700:     *dcp = dc0;
                    701:     *ev = fm;
                    702:     return fn;
                    703:   }
1.3       noro      704: }
                    705:
1.18      noro      706: void sfgcdgen(P f,ML blist,ML *clistp)
1.3       noro      707: {
1.34      noro      708:   int i;
                    709:   int n,d,np;
                    710:   UM wf,wm,wx,wy,wu,wv,wa,wb,wg,q,tum;
                    711:   UM *in,*out;
                    712:   ML clist;
                    713:
                    714:   n = UDEG(f); np = blist->n;
                    715:   d = 2*n;
                    716:   q = W_UMALLOC(d); wf = W_UMALLOC(d);
                    717:   wm = W_UMALLOC(d); wx = W_UMALLOC(d);
                    718:   wy = W_UMALLOC(d); wu = W_UMALLOC(d);
                    719:   wv = W_UMALLOC(d); wg = W_UMALLOC(d);
                    720:   wa = W_UMALLOC(d); wb = W_UMALLOC(d);
                    721:   ptosfum(f,wf); DEG(wg) = 0; COEF(wg)[0] = _onesf();
                    722:   *clistp = clist = MLALLOC(np); clist->n = np;
                    723:   for ( i = 0, in = (UM *)blist->c, out = (UM *)clist->c; i < np; i++ ) {
                    724:     divsfum(wf,in[i],q); tum = wf; wf = q; q = tum;
                    725:     cpyum(wf,wx); cpyum(in[i],wy);
                    726:     eucsfum(wx,wy,wa,wb); mulsfum(wa,wg,wm);
                    727:     DEG(wm) = divsfum(wm,in[i],q); out[i] = UMALLOC(DEG(wm));
                    728:     cpyum(wm,out[i]); mulsfum(q,wf,wu);
                    729:     mulsfum(wg,wb,wv); addsfum(wu,wv,wg);
                    730:   }
1.3       noro      731: }
                    732:
1.14      noro      733: /* f = g0*h0 mod y -> f = gk*hk mod y^(dy+1), f is replaced by hk */
1.3       noro      734:
1.18      noro      735: void sfhenmain2(BM f,UM g0,UM h0,int dy,BM *gp)
1.4       noro      736: {
1.34      noro      737:   int i,k;
                    738:   int dx;
                    739:   UM wt,wa,wb,q,w1,w2,wh1,wg1,ws;
                    740:   UM wc,wd,we,wz;
                    741:   BM wb0,wb1;
                    742:   int dg,dh;
                    743:   BM fk,gk,hk;
                    744:
                    745:   if ( DEG(f) < dy )
                    746:     error("sfhenmain2 : invalid input");
                    747:
                    748:   dx = degbm(f);
                    749:   dg = DEG(g0);
                    750:   dh = DEG(h0);
                    751:
                    752:   W_BMALLOC(dx,dy,wb0); W_BMALLOC(dx,dy,wb1);
                    753:   wt = W_UMALLOC(dx); ws = W_UMALLOC(dx); q = W_UMALLOC(2*dx);
                    754:   wg1 = W_UMALLOC(2*dx); wh1 = W_UMALLOC(2*dx);
                    755:
                    756:   /* fk = gk*hk mod y^k */
                    757:   W_BMALLOC(dx,dy,fk);
                    758:   cpyum(COEF(f)[0],COEF(fk)[0]);
                    759:   gk = BMALLOC(dg,dy);
                    760:   cpyum(g0,COEF(gk)[0]);
                    761:   W_BMALLOC(dh,dy,hk);
                    762:   cpyum(h0,COEF(hk)[0]);
                    763:
                    764:   wc = W_UMALLOC(2*dx); wd = W_UMALLOC(2*dx);
                    765:   we = W_UMALLOC(2*dx); wz = W_UMALLOC(2*dx);
                    766:
                    767:   /* compute wa,wb s.t. wa*g0+wb*h0 = 1 mod y */
                    768:   w1 = W_UMALLOC(dg); cpyum(g0,w1);
                    769:   w2 = W_UMALLOC(dh); cpyum(h0,w2);
                    770:   wa = W_UMALLOC(2*dx); wb = W_UMALLOC(2*dx);  /* XXX */
                    771:   eucsfum(w1,w2,wa,wb);
                    772:
                    773:   if ( debug_sfbfctr)
                    774:     fprintf(stderr,"dy=%d\n",dy);
                    775:   for ( k = 1; k <= dy; k++ ) {
                    776:     if ( debug_sfbfctr)
                    777:       fprintf(stderr,".");
                    778:
                    779:     /* at this point, f = gk*hk mod y^k */
                    780:
                    781:     /* clear wt */
                    782:     clearum(wt,dx);
                    783:
                    784:     /* wt = (f-gk*hk)/y^k */
                    785:     subsfum(COEF(f)[k],COEF(fk)[k],wt);
                    786:
                    787:     /* compute wf1,wg1 s.t. wh1*g0+wg1*h0 = wt */
                    788:     mulsfum(wa,wt,wh1); DEG(wh1) = divsfum(wh1,h0,q);
                    789:     mulsfum(wh1,g0,wc); subsfum(wt,wc,wd); DEG(wd) = divsfum(wd,h0,wg1);
1.4       noro      790:
1.34      noro      791:     /* check */
1.4       noro      792: #if 0
1.34      noro      793:     if ( DEG(wd) >= 0 || DEG(wg1) > ng )
                    794:       error("henmain2 : cannot happen(adj)");
1.4       noro      795:
1.34      noro      796:     mulsfum(wg1,h0,wc); mulsfum(wh1,g0,wd); addsfum(wc,wd,we);
                    797:     subsfum(we,wt,wz);
                    798:     if ( DEG(wz) >= 0 )
                    799:       error("henmain2 : cannot happen");
1.4       noro      800: #endif
                    801:
1.34      noro      802:     /* fk += ((wg1*hk+wh1*gk)*y^k+wg1*wh1*y^(2*k) mod y^(dy+1) */
                    803:     /* wb0 = wh1*y^k */
                    804:     clearbm(dx,wb0);
                    805:     cpyum(wh1,COEF(wb0)[k]);
                    806:
                    807:     /* wb1 = gk*wb0 mod y^(dy+1) */
                    808:     clearbm(dx,wb1);
                    809:     mulsfbm(gk,wb0,wb1);
                    810:     /* fk += wb1 */
                    811:     addtosfbm(wb1,fk);
                    812:
                    813:     /* wb0 = wg1*y^k */
                    814:     clearbm(dx,wb0);
                    815:     cpyum(wg1,COEF(wb0)[k]);
                    816:
                    817:     /* wb1 = hk*wb0 mod y^(dy+1) */
                    818:     clearbm(dx,wb1);
                    819:     mulsfbm(hk,wb0,wb1);
                    820:     /* fk += wb1 */
                    821:     addtosfbm(wb1,fk);
                    822:
                    823:     /* fk += wg1*wh1*y^(2*k) mod y^(dy+1) */
                    824:     if ( 2*k <= dy ) {
                    825:       mulsfum(wg1,wh1,wt); addsfum(COEF(fk)[2*k],wt,ws);
                    826:       cpyum(ws,COEF(fk)[2*k]);
                    827:     }
                    828:
                    829:     /* gk += wg1*y^k, hk += wh1*y^k */
                    830:     cpyum(wg1,COEF(gk)[k]);
                    831:     cpyum(wh1,COEF(hk)[k]);
                    832:   }
                    833:   if ( debug_sfbfctr)
                    834:     fprintf(stderr,"\n");
                    835:   *gp = gk;
                    836:   DEG(f) = dy;
                    837:   for ( i = 0; i <= dy; i++ )
                    838:     cpyum(COEF(hk)[i],COEF(f)[i]);
1.27      noro      839: }
                    840:
                    841: /* a0*g+b0*h = 1 mod y -> a*g+b*h = 1 mod y^(dy+1) */
                    842:
                    843: void sfexgcd_by_hensel(BM g,BM h,int dy,BM *ap,BM *bp)
                    844: {
1.34      noro      845:   int i,k;
                    846:   int dx;
                    847:   UM wt,wa,wb,q,w1,w2,ws;
                    848:   UM wc,wd,we,wz,wa1,wb1;
                    849:   BM wz0,wz1;
                    850:   int dg,dh;
                    851:   BM a,b,c;
                    852:
                    853:   dg = degbm(g);
                    854:   dh = degbm(h);
                    855:   dx = dg+dh;
                    856:
                    857:   a = BMALLOC(dh,dy);
                    858:   b = BMALLOC(dg,dy);
                    859:   /* c holds a*g+b*h-1 */
                    860:   c = BMALLOC(dg+dh,dy);
                    861:
                    862:   W_BMALLOC(dx,dy,wz0); W_BMALLOC(dx,dy,wz1);
                    863:
                    864:   wt = W_UMALLOC(dx); ws = W_UMALLOC(dx); q = W_UMALLOC(2*dx);
                    865:   wa1 = W_UMALLOC(2*dx); wb1 = W_UMALLOC(2*dx);
                    866:   wc = W_UMALLOC(2*dx); wd = W_UMALLOC(2*dx);
                    867:   we = W_UMALLOC(2*dx); wz = W_UMALLOC(2*dx);
                    868:
                    869:   /* compute wa,wb s.t. wa*g0+wb*h0 = 1 mod y */
                    870:   w1 = W_UMALLOC(dg); cpyum(COEF(g)[0],w1);
                    871:   w2 = W_UMALLOC(dh); cpyum(COEF(h)[0],w2);
                    872:   wa = W_UMALLOC(2*dx); wb = W_UMALLOC(2*dx);  /* XXX */
                    873:   eucsfum(w1,w2,wa,wb);
                    874:   cpyum(wa,COEF(a)[0]); cpyum(wb,COEF(b)[0]);
                    875:
                    876:   /* initialize c to a*g+b*h-1 */
                    877:   mulsfbm(a,g,c); mulsfbm(b,h,wz0); addtosfbm(wz0,c);
                    878:   COEF(COEF(c)[0])[0] = 0;
                    879:
                    880:   if ( debug_sfbfctr)
                    881:     fprintf(stderr,"dy=%d\n",dy);
                    882:   for ( k = 1; k <= dy; k++ ) {
                    883:     if ( debug_sfbfctr)
                    884:       fprintf(stderr,".");
                    885:
                    886:     /* at this point, a*g+b*h = 1 mod y^k, c = a*g+b*h-1 */
                    887:
                    888:     /* wt = -((a*g+b*h-1)/y^k) */
                    889:     cpyum(COEF(c)[k],wt);
                    890:     for ( i = DEG(wt); i >= 0; i-- )
                    891:       COEF(wt)[i] = _chsgnsf(COEF(wt)[i]);
                    892:
                    893:     /* compute wa1,wb1 s.t. wa1*g0+wb1*h0 = wt */
                    894:     mulsfum(wa,wt,wa1); DEG(wa1) = divsfum(wa1,COEF(h)[0],q);
                    895:     mulsfum(wa1,COEF(g)[0],wc); subsfum(wt,wc,wd);
                    896:     DEG(wd) = divsfum(wd,COEF(h)[0],wb1);
                    897:
                    898:     /* c += ((wa1*g+wb1*h)*y^k mod y^(dy+1) */
                    899:     /* wz0 = wa1*y^k */
                    900:     clearbm(dx,wz0);
                    901:     cpyum(wa1,COEF(wz0)[k]);
                    902:
                    903:     /* wz1 = wz0*g mod y^(dy+1) */
                    904:     clearbm(dx,wz1);
                    905:     mulsfbm(g,wz0,wz1);
                    906:     /* c += wz1 */
                    907:     addtosfbm(wz1,c);
                    908:
                    909:     /* wz0 = wb1*y^k */
                    910:     clearbm(dx,wz0);
                    911:     cpyum(wb1,COEF(wz0)[k]);
                    912:
                    913:     /* wz1 = wz0*h mod y^(dy+1) */
                    914:     clearbm(dx,wz1);
                    915:     mulsfbm(h,wz0,wz1);
                    916:     /* c += wz1 */
                    917:     addtosfbm(wz1,c);
                    918:
                    919:     /* a += wa1*y^k, b += wb1*y^k */
                    920:     cpyum(wa1,COEF(a)[k]);
                    921:     cpyum(wb1,COEF(b)[k]);
                    922:   }
                    923:   if ( debug_sfbfctr)
                    924:     fprintf(stderr,"\n");
                    925:   DEG(a) = dy;
                    926:   DEG(b) = dy;
                    927:   *ap = a;
                    928:   *bp = b;
1.3       noro      929: }
                    930:
1.5       noro      931: /* fl->c[i] = coef_y(f,i) */
                    932:
1.18      noro      933: void ptosfbm(int dy,P f,BM fl)
1.5       noro      934: {
1.34      noro      935:   DCP dc;
                    936:   int d,i,dx;
                    937:   UM t;
                    938:
                    939:   dx = QTOS(DEG(DC(f)));
                    940:   if ( DEG(fl) < dy )
                    941:     error("ptosfbm : invalid input");
                    942:   DEG(fl) = dy;
                    943:   clearbm(dx,fl);
                    944:   t = UMALLOC(dy);
                    945:   for ( dc = DC(f); dc; dc = NEXT(dc) ) {
                    946:     d = QTOS(DEG(dc));
                    947:     ptosfum(COEF(dc),t);
                    948:     for ( i = 0; i <= DEG(t); i++ )
                    949:       COEF(COEF(fl)[i])[d] = COEF(t)[i];
                    950:   }
                    951:   for ( i = 0; i <= dy; i++ )
                    952:     degum(COEF(fl)[i],dx);
1.5       noro      953: }
                    954:
                    955: /* x : main variable */
                    956:
1.18      noro      957: void sfbmtop(BM f,V x,V y,P *fp)
1.5       noro      958: {
1.34      noro      959:   UM *c;
                    960:   int i,j,d,a,dy;
                    961:   GFS b;
                    962:   DCP dc0,dc,dct;
                    963:
                    964:   dy = DEG(f);
                    965:   c = COEF(f);
                    966:   d = degbm(f);
                    967:
                    968:   dc0 = 0;
                    969:   for ( i = 0; i <= d; i++ ) {
                    970:     dc = 0;
                    971:     for ( j = 0; j <= dy; j++ ) {
                    972:       if ( DEG(c[j]) >= i && (a = COEF(c[j])[i]) ) {
                    973:         NEWDC(dct);
                    974:         STOQ(j,DEG(dct));
                    975:         iftogfs(a,&b);
                    976:         COEF(dct) = (P)b;
                    977:         NEXT(dct) = dc;
                    978:         dc = dct;
                    979:       }
                    980:     }
                    981:     if ( dc ) {
                    982:       NEWDC(dct);
                    983:       STOQ(i,DEG(dct));
                    984:       MKP(y,dc,COEF(dct));
                    985:       NEXT(dct) = dc0;
                    986:       dc0 = dct;
                    987:     }
                    988:   }
                    989:   if ( dc0 )
                    990:     MKP(x,dc0,*fp);
                    991:   else
                    992:     *fp = 0;
1.8       noro      993: }
                    994:
1.18      noro      995: void sfsqfr(P f,DCP *dcp)
1.14      noro      996: {
1.34      noro      997:   Obj obj;
                    998:   DCP dc;
                    999:   VL vl;
                   1000:
                   1001:   simp_ff((Obj)f,&obj); f = (P)obj;
                   1002:   clctv(CO,f,&vl);
                   1003:   if ( !vl ) {
                   1004:     /* f is a const */
                   1005:     NEWDC(dc); DEG(dc) = ONE; COEF(dc) = f; NEXT(dc) = 0; *dcp = dc;
                   1006:   } else if ( !NEXT(vl) )
                   1007:     sfusqfr(f,dcp);
                   1008:   else
                   1009:     sqfrsf(vl,f,dcp);
1.14      noro     1010: }
                   1011:
1.18      noro     1012: void sfusqfr(P f,DCP *dcp)
1.14      noro     1013: {
1.34      noro     1014:   DCP dc,dct;
                   1015:   struct oDUM *udc;
                   1016:   V x;
                   1017:   P lc;
                   1018:   int n,i;
                   1019:   UM mf;
                   1020:
                   1021:   x = VR(f);
                   1022:   n = getdeg(x,f);
                   1023:   mf = W_UMALLOC(n);
                   1024:   ptosfum(f,mf);
                   1025:   lc = COEF(DC(f));
                   1026:   if ( !_isonesf(COEF(mf)[n]) ) {
                   1027:     monicsfum(mf);
                   1028:   }
                   1029:   W_CALLOC(n+1,struct oDUM,udc);
                   1030:   gensqfrsfum(mf,udc);
                   1031:   for ( i = 0, dc = 0; udc[i].f; i++ ) {
                   1032:     NEWDC(dct); STOQ(udc[i].n,DEG(dct));
                   1033:     sfumtop(x,udc[i].f,&COEF(dct));
                   1034:     NEXT(dct) = dc; dc = dct;
                   1035:   }
                   1036:   NEWDC(dct); DEG(dct) = ONE; COEF(dct) = (P)lc; NEXT(dct) = dc;
                   1037:   *dcp = dct;
1.14      noro     1038: }
                   1039:
1.24      noro     1040: #if 0
1.21      noro     1041: void sfbsqfrmain(P f,V x,V y,DCP *dcp)
                   1042: {
1.34      noro     1043:   /* XXX*/
1.21      noro     1044: }
                   1045:
                   1046: /* f is bivariate */
                   1047:
1.18      noro     1048: void sfbsqfr(P f,V x,V y,DCP *dcp)
1.14      noro     1049: {
1.34      noro     1050:   P t,rf,cx,cy;
                   1051:   VL vl,rvl;
                   1052:   DCP dcx,dcy,dct,dc;
                   1053:   struct oVL vl0,vl1;
                   1054:
                   1055:   /* cy(y) = cont(f,x), f /= cy */
                   1056:   cont_pp_sfp(vl,f,&cy,&t); f = t;
                   1057:   /* rvl = [y,x] */
                   1058:   reordvar(vl,y,&rvl); reorderp(rvl,vl,f,&rf);
                   1059:   /* cx(x) = cont(rf,y), Rf /= cy */
                   1060:   cont_pp_sfp(rvl,rf,&cx,&t); rf = t;
                   1061:   reorderp(vl,rvl,rf,&f);
                   1062:
                   1063:   /* f -> cx*cy*f */
                   1064:   sfsqfr(cx,&dcx); dcx = NEXT(dcx);
                   1065:   sfsqfr(cy,&dcy); dcy = NEXT(dcy);
                   1066:   if ( dcx ) {
                   1067:     for ( dct = dcx; NEXT(dct); dct = NEXT(dct) );
                   1068:     NEXT(dct) = dcy;
                   1069:   } else
                   1070:     dcx = dcy;
                   1071:   if ( OID(f) == O_N )
                   1072:     *dcp = dcx;
                   1073:   else {
                   1074:     /* f must be bivariate */
                   1075:     sfbsqfrmain(f,x,y,&dc);
                   1076:     if ( dcx ) {
                   1077:       for ( dct = dcx; NEXT(dct); dct = NEXT(dct) );
                   1078:       NEXT(dct) = dc;
                   1079:     } else
                   1080:       dcx = dc;
                   1081:     *dcp = dcx;
                   1082:   }
1.14      noro     1083: }
1.24      noro     1084: #endif
1.14      noro     1085:
1.8       noro     1086: void sfdtest(P,ML,V,V,DCP *);
                   1087:
1.21      noro     1088: /* if degbound >= 0 find factor s.t. deg_x(factor) <= degbound */
                   1089:
                   1090: void sfbfctr(P f,V x,V y,int degbound,DCP *dcp)
1.8       noro     1091: {
1.34      noro     1092:   ML list;
                   1093:   P sf;
                   1094:   GFS ev;
                   1095:   DCP dc,dct;
                   1096:   BM fl;
                   1097:   int dx,dy;
                   1098:
                   1099:   /* sf(x) = f(x+ev) = list->c[0]*list->c[1]*... */
                   1100:   sfhensel(5,f,x,y,degbound,&ev,&sf,&list);
                   1101:   if ( list->n == 0 )
                   1102:     error("sfbfctr : short of evaluation points");
                   1103:   else if ( list->n == 1 ) {
                   1104:     /* f is irreducible */
                   1105:     NEWDC(dc); DEG(dc) = ONE; COEF(dc) = f; NEXT(dc) = 0;
                   1106:     *dcp = dc;
                   1107:     return;
                   1108:   }
                   1109:   sfdtest(sf,list,x,y,&dc);
                   1110:   if ( ev ) {
                   1111:     dx = getdeg(x,sf);
                   1112:     dy = getdeg(y,sf);
                   1113:     W_BMALLOC(dx,dy,fl);
                   1114:     for ( dct = dc; dct; dct = NEXT(dct) ) {
                   1115:       ptosfbm(dy,COEF(dct),fl);
                   1116:       shiftsfbm(fl,_chsgnsf(FTOIF(CONT(ev))));
                   1117:       sfbmtop(fl,x,y,&COEF(dct));
                   1118:     }
                   1119:   }
                   1120:   *dcp = dc;
1.26      noro     1121: }
                   1122:
                   1123: /* returns shifted f, shifted factors and the eval pt */
                   1124:
                   1125: void sfbfctr_shift(P f,V x,V y,int degbound,GFS *evp,P *sfp,DCP *dcp)
                   1126: {
1.34      noro     1127:   ML list;
                   1128:   P sf;
                   1129:   GFS ev;
                   1130:   DCP dc,dct;
                   1131:   int dx,dy;
                   1132:
                   1133:   /* sf(x) = f(x+ev) = list->c[0]*list->c[1]*... */
                   1134:   sfhensel(5,f,x,y,degbound,&ev,&sf,&list);
                   1135:   if ( list->n == 0 )
                   1136:     error("sfbfctr_shift : short of evaluation points");
                   1137:   else if ( list->n == 1 ) {
                   1138:     /* f is irreducible */
                   1139:     NEWDC(dc); DEG(dc) = ONE; COEF(dc) = f; NEXT(dc) = 0;
                   1140:     *evp = 0;
                   1141:     *sfp = f;
                   1142:     *dcp = dc;
                   1143:   } else {
                   1144:     sfdtest(sf,list,x,y,dcp);
                   1145:     *evp = ev;
                   1146:     *sfp = sf;
                   1147:   }
1.8       noro     1148: }
                   1149:
1.14      noro     1150: /* f = f(x,y) = list->c[0]*list->c[1]*... mod y^(list->bound+1) */
1.8       noro     1151:
1.18      noro     1152: void sfdtest(P f,ML list,V x,V y,DCP *dcp)
1.8       noro     1153: {
1.34      noro     1154:   int np,dx,dy;
                   1155:   int i,j,k,bound;
                   1156:   int *win;
                   1157:   P g,lcg,factor,cofactor,lcyx;
                   1158:   P csum;
                   1159:   DCP dcf,dcf0,dc;
                   1160:   BM *c;
                   1161:   BM lcy;
                   1162:   UM lcg0,lcy0,w;
                   1163:   UM *d1c;
                   1164:   ML wlist;
                   1165:   struct oVL vl1,vl0;
                   1166:   VL vl;
                   1167:   int z,dt,dtok;
                   1168:
                   1169:   /* vl = [x,y] */
                   1170:   vl0.v = x; vl0.next = &vl1; vl1.v = y; vl1.next = 0; vl = &vl0;
                   1171:
                   1172:   /* setup various structures and arrays */
                   1173:   dx = getdeg(x,f);
                   1174:   dy = getdeg(y,f);
                   1175:   np = list->n;
                   1176:   win = W_ALLOC(np+1);
                   1177:   wlist = W_MLALLOC(np);
                   1178:   wlist->n = list->n;
                   1179:   bound = wlist->bound = list->bound;
                   1180:   c = (BM *)COEF(wlist);
                   1181:   bcopy((char *)COEF(list),(char *)c,(int)(sizeof(BM)*np));
                   1182:
                   1183:   lcg0 = W_UMALLOC(2*dy);
                   1184:
                   1185:   /* initialize g by f */
                   1186:   g = f;
                   1187:
                   1188:   /* initialize lcg */
                   1189:   mulp(vl,g,COEF(DC(g)),&lcg);
                   1190:
                   1191:   /* initialize lcg0 */
                   1192:   const_term(lcg,lcg0);
                   1193:
                   1194:   /* initialize csum = lcg(1) */
                   1195:   sfcsump(vl,lcg,&csum);
                   1196:
                   1197:   /* initialize lcy by LC(f) */
                   1198:   W_BMALLOC(0,dy,lcy);
                   1199:   NEWDC(dc); COEF(dc) = COEF(DC(g)); DEG(dc) = 0;
                   1200:   NEWP(lcyx); VR(lcyx) = x; DC(lcyx) = dc;
                   1201:   ptosfbm(dy,lcyx,lcy);
                   1202:
                   1203:   /* initialize lcy0 by LC(f) */
                   1204:   lcy0 = W_UMALLOC(bound);
                   1205:   ptosfum(COEF(DC(g)),lcy0);
                   1206:
                   1207:   /* ((d-1 coefs)*lcy0 */
                   1208:   d1c = (UM *)W_ALLOC(np*sizeof(UM));
                   1209:   w = W_UMALLOC(2*bound);
                   1210:   for ( i = 1; i < np; i++ ) {
                   1211:     extractcoefbm(c[i],degbm(c[i])-1,w);
                   1212:     d1c[i] = W_UMALLOC(2*bound);
                   1213:     mulsfum(w,lcy0,d1c[i]);
                   1214:     /* d1c[i] = d1c[i] mod y^(bound+1) */
                   1215:     if ( DEG(d1c[i]) > bound ) {
                   1216:       for ( j = DEG(d1c[i]); j > bound; j-- )
                   1217:         COEF(d1c[i])[j] = 0;
                   1218:       degum(d1c[i],bound);
                   1219:     }
                   1220:   }
                   1221:
                   1222:   if ( debug_sfbfctr)
                   1223:     fprintf(stderr,"np = %d\n",np);
                   1224:   dtok = 0;
                   1225:   for ( g = f, k = 1, dcf = dcf0 = 0, win[0] = 1, --np, z = 0; ; z++ ) {
                   1226:     if ( debug_sfbfctr && !(z % 1000) ) fprintf(stderr,".");
                   1227:     dt = sfdegtest(dy,bound,d1c,k,win);
                   1228:     if ( dt )
                   1229:       dtok++;
                   1230:     if ( dt && sfdtestmain(vl,lcg,lcg0,lcy,csum,wlist,
                   1231:         k,win,&factor,&cofactor) ) {
                   1232:       NEXTDC(dcf0,dcf); DEG(dcf) = ONE; COEF(dcf) = factor;
                   1233:       g = cofactor;
                   1234:
                   1235:       /* update lcg */
                   1236:       mulp(vl,g,COEF(DC(g)),&lcg);
                   1237:
                   1238:       /* update lcg0 */
                   1239:       const_term(lcg,lcg0);
                   1240:
                   1241:       /* update csum */
                   1242:       sfcsump(vl,lcg,&csum);
                   1243:
                   1244:       /* update dy */
                   1245:       dy = getdeg(y,g);
                   1246:
                   1247:       /* update lcy */
                   1248:       clearbm(0,lcy);
                   1249:       COEF(dc) = COEF(DC(g));
                   1250:       ptosfbm(dy,lcyx,lcy);
                   1251:
                   1252:       for ( i = 0; i < k - 1; i++ )
                   1253:         for ( j = win[i] + 1; j < win[i + 1]; j++ )
                   1254:           c[j-i-1] = c[j];
                   1255:       for ( j = win[k-1] + 1; j <= np; j++ )
                   1256:           c[j-k] = c[j];
                   1257:       if ( ( np -= k ) < k )
                   1258:         break;
                   1259:       if ( np - win[0] + 1 < k )
                   1260:         if ( ++k > np )
                   1261:           break;
                   1262:         else
                   1263:           for ( i = 0; i < k; i++ )
                   1264:             win[i] = i + 1;
                   1265:       else
                   1266:         for ( i = 1; i < k; i++ )
                   1267:           win[i] = win[0] + i;
                   1268:
                   1269:
                   1270:       /* update lcy0  */
                   1271:       ptosfum(COEF(DC(g)),lcy0);
                   1272:
                   1273:       /* update d-1 coeffs */
                   1274:       for ( i = 1; i <= np; i++ ) {
                   1275:         extractcoefbm(c[i],degbm(c[i])-1,w);
                   1276:         mulsfum(w,lcy0,d1c[i]);
                   1277:         /* d1c[i] = d1c[1] mod y^(bound+1) */
                   1278:         if ( DEG(d1c[i]) > bound ) {
                   1279:           for ( j = DEG(d1c[i]); j > bound; j-- )
                   1280:             COEF(d1c[i])[j] = 0;
                   1281:           degum(d1c[i],bound);
                   1282:         }
                   1283:       }
                   1284:     } else if ( !ncombi(1,np,k,win) )
                   1285:       if ( k == np )
                   1286:         break;
                   1287:       else
                   1288:         for ( i = 0, ++k; i < k; i++ )
                   1289:           win[i] = i + 1;
                   1290:   }
                   1291:   if ( debug_sfbfctr )
                   1292:     fprintf(stderr,"total %d, omitted by degtest %d\n",z,z-dtok);
                   1293:   NEXTDC(dcf0,dcf); COEF(dcf) = g;
                   1294:   DEG(dcf) = ONE; NEXT(dcf) = 0; *dcp = dcf0;
1.8       noro     1295: }
                   1296:
1.20      noro     1297: void extractcoefbm(BM f,int dx,UM r)
1.19      noro     1298: {
1.34      noro     1299:   int j;
                   1300:   UM fj;
1.19      noro     1301:
1.34      noro     1302:   for ( j = DEG(f); j >= 0; j-- ) {
                   1303:     fj = COEF(f)[j];
                   1304:     if ( fj && DEG(fj) >= dx ) {
                   1305:       COEF(r)[j] = COEF(fj)[dx];
                   1306:     } else
                   1307:       COEF(r)[j] = 0;
                   1308:   }
                   1309:   degum(r,DEG(f));
1.19      noro     1310: }
                   1311:
                   1312: /* deg_y(prod mod y^(bound+1)) <= dy ? */
                   1313:
1.20      noro     1314: int sfdegtest(int dy,int bound,UM *d1c,int k,int *in)
1.19      noro     1315: {
1.34      noro     1316:   int i,j;
                   1317:   UM w,w1,wt;
                   1318:   BM t;
                   1319:
                   1320:   w = W_UMALLOC(bound);
                   1321:   w1 = W_UMALLOC(bound);
                   1322:   clearum(w,bound);
                   1323:   for ( i = 0; i < k; i++ ) {
                   1324:     addsfum(w,d1c[in[i]],w1); wt = w; w = w1; w1 = wt;
                   1325:   }
                   1326:   return DEG(w) <= dy ? 1 : 0;
1.19      noro     1327: }
                   1328:
1.9       noro     1329: /* lcy = LC(g), lcg = lcy*g, lcg0 = const part of lcg */
1.19      noro     1330:
1.18      noro     1331: int sfdtestmain(VL vl,P lcg,UM lcg0,BM lcy,P csum,ML list,
1.34      noro     1332:   int k,int *in,P *fp,P *cofp)
1.8       noro     1333: {
1.34      noro     1334:   P fmul,csumg,q,cont;
                   1335:   V x,y;
1.8       noro     1336:
1.34      noro     1337:   x = vl->v;
                   1338:   y = vl->next->v;
                   1339:   if (!sfctest(lcg0,lcy,list,k,in))
                   1340:     return 0;
                   1341:   mulsfbmarray(UDEG(lcg),lcy,list,k,in,x,y,&fmul);
                   1342:   if ( csum ) {
                   1343:     sfcsump(vl,fmul,&csumg);
                   1344:     if ( csumg ) {
                   1345:       if ( !divtp(vl,csum,csumg,&q) )
                   1346:         return 0;
                   1347:     }
                   1348:   }
                   1349:   if ( divtp_by_sfbm(vl,lcg,fmul,&q) ) {
                   1350:     cont_pp_sfp(vl,fmul,&cont,fp);
                   1351:     cont_pp_sfp(vl,q,&cont,cofp);
                   1352:     return 1;
                   1353:   } else
                   1354:     return 0;
1.8       noro     1355: }
                   1356:
1.18      noro     1357: void const_term(P f,UM c)
1.9       noro     1358: {
1.34      noro     1359:   DCP dc;
1.9       noro     1360:
1.34      noro     1361:   for ( dc = DC(f); dc && DEG(dc); dc = NEXT(dc) );
                   1362:   if ( dc )
                   1363:     ptosfum(COEF(dc),c);
                   1364:   else
                   1365:     DEG(c) = -1;
1.9       noro     1366: }
                   1367:
1.18      noro     1368: void const_term_sfbm(BM f,UM c)
1.9       noro     1369: {
1.34      noro     1370:   int i,dy;
1.9       noro     1371:
1.34      noro     1372:   dy = DEG(f);
                   1373:   for ( i = 0; i <= dy; i++ )
                   1374:     if ( DEG(COEF(f)[i]) >= 0 )
                   1375:       COEF(c)[i] = COEF(COEF(f)[i])[0];
                   1376:     else
                   1377:       COEF(c)[i] = 0;
                   1378:   degum(c,dy);
1.9       noro     1379: }
                   1380:
                   1381: /* lcy*(product of const part) | lcg0 ? */
                   1382:
1.18      noro     1383: int sfctest(UM lcg0,BM lcy,ML list,int k,int *in)
1.8       noro     1384: {
1.34      noro     1385:   int dy,i,dr;
                   1386:   UM t,s,u,w;
                   1387:   BM *l;
                   1388:
                   1389:   dy = list->bound;
                   1390:   t = W_UMALLOC(2*dy);
                   1391:   s = W_UMALLOC(2*dy);
                   1392:   u = W_UMALLOC(2*dy);
                   1393:   const_term_sfbm(lcy,t);
                   1394:   if ( DEG(t) < 0 )
                   1395:     return 1;
                   1396:
                   1397:   l = (BM *)list->c;
                   1398:   for ( i = 0; i < k; i++ ) {
                   1399:     const_term_sfbm(l[in[i]],s);
                   1400:     mulsfum(t,s,u);
                   1401:     if ( DEG(u) > dy )
                   1402:       degum(u,dy);
                   1403:     w = t; t = u; u = w;
                   1404:   }
                   1405:   cpyum(lcg0,s);
                   1406:   dr = divsfum(s,t,u);
                   1407:   if ( dr >= 0 )
                   1408:     return 0;
                   1409:   else
                   1410:     return 1;
1.8       noro     1411: }
                   1412:
                   1413: /* main var of f is x */
                   1414:
1.18      noro     1415: void mulsfbmarray(int dx,BM lcy,ML list,int k,int *in,V x,V y,P *g)
1.8       noro     1416: {
1.34      noro     1417:   int dy,i;
                   1418:   BM wb0,wb1,t;
                   1419:   BM *l;
                   1420:
                   1421:   dy = list->bound;
                   1422:   W_BMALLOC(dx,dy,wb0); W_BMALLOC(dx,dy,wb1);
                   1423:   l = (BM *)list->c;
                   1424:   clearbm(dx,wb0);
                   1425:   mulsfbm(lcy,l[in[0]],wb0);
                   1426:   for ( i = 1; i < k; i++ ) {
                   1427:     clearbm(dx,wb1);
                   1428:     mulsfbm(l[in[i]],wb0,wb1);
                   1429:     t = wb0; wb0 = wb1; wb1 = t;
                   1430:   }
                   1431:   sfbmtop(wb0,x,y,g);
1.8       noro     1432: }
                   1433:
1.18      noro     1434: void sfcsump(VL vl,P f,P *s)
1.8       noro     1435: {
1.34      noro     1436:   P t,u;
                   1437:   DCP dc;
1.8       noro     1438:
1.34      noro     1439:   for ( dc = DC(f), t = 0; dc; dc = NEXT(dc) ) {
                   1440:     addp(vl,COEF(dc),t,&u); t = u;
                   1441:   }
                   1442:   *s = t;
1.8       noro     1443: }
                   1444:
                   1445: /* *fp = primitive part of f w.r.t. x */
                   1446:
1.18      noro     1447: void cont_pp_sfp(VL vl,P f,P *cp,P *fp)
1.8       noro     1448: {
1.34      noro     1449:   V x,y;
                   1450:   int d;
                   1451:   UM t,s,gcd;
                   1452:   DCP dc;
                   1453:   GFS g;
                   1454:
                   1455:   x = vl->v;
                   1456:   y = vl->next->v;
                   1457:   d = getdeg(y,f);
                   1458:   if ( d == 0 ) {
                   1459:     itogfs(1,&g);
                   1460:     *cp = (P)g;
                   1461:     *fp = f;  /* XXX */
                   1462:   } else {
                   1463:     t = W_UMALLOC(2*d);
                   1464:     s = W_UMALLOC(2*d);
                   1465:     gcd = W_UMALLOC(2*d);
                   1466:     dc = DC(f);
                   1467:     ptosfum(COEF(dc),gcd);
                   1468:     for ( dc = NEXT(dc); dc; dc = NEXT(dc) ) {
                   1469:       ptosfum(COEF(dc),t);
                   1470:       gcdsfum(gcd,t,s);
                   1471:       cpyum(s,gcd);
                   1472:     }
                   1473:     sfumtop(y,gcd,cp);
                   1474:     divsp(vl,f,*cp,fp);
                   1475:   }
1.11      noro     1476: }
                   1477:
1.18      noro     1478: int divtp_by_sfbm(VL vl,P f,P g,P *qp)
1.11      noro     1479: {
1.34      noro     1480:   V x,y;
                   1481:   int fx,fy,gx,gy;
                   1482:   BM fl,gl,ql;
                   1483:   UM *cf,*cg,*cq;
                   1484:   UM hg,q,t,s;
                   1485:   int i,j,dr;
                   1486:
                   1487:   x = vl->v; y = vl->next->v;
                   1488:   fx = getdeg(x,f); fy = getdeg(y,f);
                   1489:   gx = getdeg(x,g); gy = getdeg(y,g);
                   1490:
                   1491:   if ( fx < gx || fy < gy )
                   1492:     return 0;
                   1493:   W_BMALLOC(fx,fy,fl); ptosfbm(fy,f,fl); cf = COEF(fl);
                   1494:   W_BMALLOC(gx,gy,gl); ptosfbm(gy,g,gl); cg = COEF(gl);
                   1495:   W_BMALLOC(fx-gx,fy-gy,ql); cq = COEF(ql);
                   1496:
                   1497:   hg = cg[gy];
                   1498:   q = W_UMALLOC(fx); t = W_UMALLOC(fx); s = W_UMALLOC(fx);
                   1499:
                   1500:   for ( i = fy; i >= gy; i-- ) {
                   1501:     if ( DEG(cf[i]) < 0 )
                   1502:       continue;
                   1503:     dr = divsfum(cf[i],hg,q);
                   1504:     if ( dr >= 0 )
                   1505:       return 0;
                   1506:     if ( DEG(q) > fx-gx )
                   1507:       return 0;
                   1508:     cpyum(q,cq[i-gy]);
                   1509:     for ( j = 0; j <= gy; j++ ) {
                   1510:       mulsfum(cg[j],q,t);
                   1511:       subsfum(cf[j+i-gy],t,s);
                   1512:       cpyum(s,cf[j+i-gy]);
                   1513:     }
                   1514:   }
                   1515:   for ( j = gy-1; j >= 0 && DEG(cf[j]) < 0; j-- );
                   1516:   if ( j >= 0 )
                   1517:     return 0;
                   1518:   sfbmtop(ql,x,y,qp);
                   1519:   return 1;
1.16      noro     1520: }
                   1521:
                   1522: /* XXX generate an irreducible poly of degree n */
                   1523:
1.17      noro     1524: extern int current_gfs_q1;
1.22      noro     1525: extern int *current_gfs_ntoi;
1.17      noro     1526:
1.18      noro     1527: void generate_defpoly_sfum(int n,UM *dp)
1.16      noro     1528: {
1.34      noro     1529:   UM r,dr,t,g;
                   1530:   UM *f;
                   1531:   int *c,*w;
                   1532:   int max,i,j;
                   1533:
                   1534:   *dp = r = UMALLOC(n);
                   1535:   DEG(r) = n;
                   1536:   c = COEF(r);
                   1537:   c[n] = _onesf();
                   1538:   max = current_gfs_q1;
                   1539:   w = (int *)ALLOCA(n*sizeof(int));
                   1540:   bzero(w,n*sizeof(int));
                   1541:
                   1542:   dr = W_UMALLOC(n); t = W_UMALLOC(n); g = W_UMALLOC(n);
                   1543:   f = (UM *)ALLOCA((n+1)*sizeof(UM));
                   1544:   while ( 1 ) {
                   1545:     for ( i = 0; i < n && w[i] == max; i++ );
                   1546:     if ( i == n ) {
                   1547:       /* XXX cannot happen */
                   1548:       error("generate_defpoly_sfum : cannot happen");
                   1549:     }
                   1550:     for ( j = 0; j < i; j++ )
                   1551:       w[j] = 0;
                   1552:     w[i]++;
                   1553:     if ( !current_gfs_ntoi )
                   1554:       for ( i = 0; i < n; i++ )
                   1555:         c[i] = w[i]?FTOIF(w[i]):0;
                   1556:     else
                   1557:       for ( i = 0; i < n; i++ )
                   1558:         c[i] = w[i]?FTOIF(w[i]-1):0;
                   1559:     if ( !c[0] )
                   1560:       continue;
                   1561:     diffsfum(r,dr); cpyum(r,t); gcdsfum(t,dr,g);
                   1562:     if ( DEG(g) > 0 )
                   1563:       continue;
                   1564:
                   1565:     czsfum(r,f);
                   1566:     for ( i = 0; f[i]; i++ );
                   1567:     if ( i == 1 )
                   1568:       return;
                   1569:   }
1.3       noro     1570: }

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