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Annotation of OpenXM_contrib2/asir2018/engine/Hgfs.c, Revision 1.1

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

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