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Annotation of OpenXM_contrib2/asir2000/lib/bfct, Revision 1.19

1.2       noro        1: /*
                      2:  * Copyright (c) 1994-2000 FUJITSU LABORATORIES LIMITED
                      3:  * All rights reserved.
                      4:  *
                      5:  * FUJITSU LABORATORIES LIMITED ("FLL") hereby grants you a limited,
                      6:  * non-exclusive and royalty-free license to use, copy, modify and
                      7:  * redistribute, solely for non-commercial and non-profit purposes, the
                      8:  * computer program, "Risa/Asir" ("SOFTWARE"), subject to the terms and
                      9:  * conditions of this Agreement. For the avoidance of doubt, you acquire
                     10:  * only a limited right to use the SOFTWARE hereunder, and FLL or any
                     11:  * third party developer retains all rights, including but not limited to
                     12:  * copyrights, in and to the SOFTWARE.
                     13:  *
                     14:  * (1) FLL does not grant you a license in any way for commercial
                     15:  * purposes. You may use the SOFTWARE only for non-commercial and
                     16:  * non-profit purposes only, such as academic, research and internal
                     17:  * business use.
                     18:  * (2) The SOFTWARE is protected by the Copyright Law of Japan and
                     19:  * international copyright treaties. If you make copies of the SOFTWARE,
                     20:  * with or without modification, as permitted hereunder, you shall affix
                     21:  * to all such copies of the SOFTWARE the above copyright notice.
                     22:  * (3) An explicit reference to this SOFTWARE and its copyright owner
                     23:  * shall be made on your publication or presentation in any form of the
                     24:  * results obtained by use of the SOFTWARE.
                     25:  * (4) In the event that you modify the SOFTWARE, you shall notify FLL by
1.3       noro       26:  * e-mail at risa-admin@sec.flab.fujitsu.co.jp of the detailed specification
1.2       noro       27:  * for such modification or the source code of the modified part of the
                     28:  * SOFTWARE.
                     29:  *
                     30:  * THE SOFTWARE IS PROVIDED AS IS WITHOUT ANY WARRANTY OF ANY KIND. FLL
                     31:  * MAKES ABSOLUTELY NO WARRANTIES, EXPRESSED, IMPLIED OR STATUTORY, AND
                     32:  * EXPRESSLY DISCLAIMS ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS
                     33:  * FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT OF THIRD PARTIES'
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                     35:  * MODIFICATIONS, EXTENSIONS, OR ADDITIONS TO THIS WARRANTY.
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                     37:  * OR OTHERWISE, SHALL FLL BE LIABLE TO YOU OR ANY OTHER PERSON FOR ANY
                     38:  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, PUNITIVE OR CONSEQUENTIAL
                     39:  * DAMAGES OF ANY CHARACTER, INCLUDING, WITHOUT LIMITATION, DAMAGES
                     40:  * ARISING OUT OF OR RELATING TO THE SOFTWARE OR THIS AGREEMENT, DAMAGES
                     41:  * FOR LOSS OF GOODWILL, WORK STOPPAGE, OR LOSS OF DATA, OR FOR ANY
                     42:  * DAMAGES, EVEN IF FLL SHALL HAVE BEEN INFORMED OF THE POSSIBILITY OF
                     43:  * SUCH DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY. EVEN IF A PART
                     44:  * OF THE SOFTWARE HAS BEEN DEVELOPED BY A THIRD PARTY, THE THIRD PARTY
                     45:  * DEVELOPER SHALL HAVE NO LIABILITY IN CONNECTION WITH THE USE,
                     46:  * PERFORMANCE OR NON-PERFORMANCE OF THE SOFTWARE.
                     47:  *
1.19    ! noro       48:  * $OpenXM: OpenXM_contrib2/asir2000/lib/bfct,v 1.18 2002/01/28 02:42:27 noro Exp $
1.10      noro       49:  */
1.1       noro       50: /* requires 'primdec' */
                     51:
1.6       noro       52: /* annihilating ideal of F^s */
1.1       noro       53:
                     54: def ann(F)
                     55: {
                     56:        V = vars(F);
                     57:        N = length(V);
1.8       noro       58:        D = newvect(N);
                     59:
                     60:        for ( I = 0; I < N; I++ )
                     61:                D[I] = [deg(F,V[I]),V[I]];
                     62:        qsort(D,compare_first);
                     63:        for ( V = [], I = N-1; I >= 0; I-- )
                     64:                V = cons(D[I][1],V);
                     65:
1.1       noro       66:        for ( I = N-1, DV = []; I >= 0; I-- )
                     67:                DV = cons(strtov("d"+rtostr(V[I])),DV);
1.8       noro       68:
                     69:        W = append([y1,y2,t],V);
1.1       noro       70:        DW = append([dy1,dy2,dt],DV);
1.8       noro       71:
                     72:        B = [1-y1*y2,t-y1*F];
1.1       noro       73:        for ( I = 0; I < N; I++ ) {
                     74:                B = cons(DV[I]+y1*diff(F,V[I])*dt,B);
                     75:        }
1.10      noro       76:
                     77:        /* homogenized (heuristics) */
1.1       noro       78:        dp_nelim(2);
1.10      noro       79:        G0 = dp_weyl_gr_main(B,append(W,DW),1,0,6);
1.1       noro       80:        G1 = [];
                     81:        for ( T = G0; T != []; T = cdr(T) ) {
                     82:                E = car(T); VL = vars(E);
                     83:                if ( !member(y1,VL) && !member(y2,VL) )
                     84:                        G1 = cons(E,G1);
                     85:        }
1.12      noro       86:        G2 = map(psi,G1,t,dt);
                     87:        G3 = map(subst,G2,t,-1-s);
                     88:        return G3;
1.1       noro       89: }
                     90:
1.10      noro       91: /*
                     92:  * compute J_f|s=r, where r = the minimal integral root of global b_f(s)
                     93:  * ann0(F) returns [MinRoot,Ideal]
                     94:  */
                     95:
                     96: def ann0(F)
                     97: {
                     98:        V = vars(F);
                     99:        N = length(V);
                    100:        D = newvect(N);
                    101:
                    102:        for ( I = 0; I < N; I++ )
                    103:                D[I] = [deg(F,V[I]),V[I]];
                    104:        qsort(D,compare_first);
                    105:        for ( V = [], I = 0; I < N; I++ )
                    106:                V = cons(D[I][1],V);
                    107:
                    108:        for ( I = N-1, DV = []; I >= 0; I-- )
                    109:                DV = cons(strtov("d"+rtostr(V[I])),DV);
                    110:
                    111:        /* XXX : heuristics */
                    112:        W = append([y1,y2,t],reverse(V));
                    113:        DW = append([dy1,dy2,dt],reverse(DV));
                    114:        WDW = append(W,DW);
                    115:
                    116:        B = [1-y1*y2,t-y1*F];
                    117:        for ( I = 0; I < N; I++ ) {
                    118:                B = cons(DV[I]+y1*diff(F,V[I])*dt,B);
                    119:        }
                    120:
                    121:        /* homogenized (heuristics) */
                    122:        dp_nelim(2);
                    123:        G0 = dp_weyl_gr_main(B,WDW,1,0,6);
                    124:        G1 = [];
                    125:        for ( T = G0; T != []; T = cdr(T) ) {
                    126:                E = car(T); VL = vars(E);
                    127:                if ( !member(y1,VL) && !member(y2,VL) )
                    128:                        G1 = cons(E,G1);
                    129:        }
1.12      noro      130:        G2 = map(psi,G1,t,dt);
                    131:        G3 = map(subst,G2,t,-1-s);
1.10      noro      132:
1.12      noro      133:        /* G3 = J_f(s) */
1.10      noro      134:
                    135:        V1 = cons(s,V); DV1 = cons(ds,DV); V1DV1 = append(V1,DV1);
1.12      noro      136:        G4 = dp_weyl_gr_main(cons(F,G3),V1DV1,0,1,0);
                    137:        Bf = weyl_minipoly(G4,V1DV1,0,s);
1.10      noro      138:
                    139:        FList = cdr(fctr(Bf));
                    140:        for ( T = FList, Min = 0; T != []; T = cdr(T) ) {
                    141:                LF = car(car(T));
                    142:                Root = -coef(LF,0)/coef(LF,1);
                    143:                if ( dn(Root) == 1 && Root < Min )
                    144:                        Min = Root;
                    145:        }
1.12      noro      146:        return [Min,map(subst,G3,s,Min)];
1.10      noro      147: }
                    148:
1.7       noro      149: def indicial1(F,V)
1.6       noro      150: {
                    151:        W = append([y1,t],V);
                    152:        N = length(V);
                    153:        B = [t-y1*F];
                    154:        for ( I = N-1, DV = []; I >= 0; I-- )
                    155:                DV = cons(strtov("d"+rtostr(V[I])),DV);
                    156:        DW = append([dy1,dt],DV);
                    157:        for ( I = 0; I < N; I++ ) {
                    158:                B = cons(DV[I]+y1*diff(F,V[I])*dt,B);
                    159:        }
                    160:        dp_nelim(1);
1.10      noro      161:
                    162:        /* homogenized (heuristics) */
1.7       noro      163:        G0 = dp_weyl_gr_main(B,append(W,DW),1,0,6);
1.6       noro      164:        G1 = map(subst,G0,y1,1);
                    165:        G2 = map(psi,G1,t,dt);
                    166:        G3 = map(subst,G2,t,-s-1);
                    167:        return G3;
                    168: }
                    169:
                    170: def psi(F,T,DT)
                    171: {
                    172:        D = dp_ptod(F,[T,DT]);
                    173:        Wmax = weight(D);
                    174:        D1 = dp_rest(D);
                    175:        for ( ; D1; D1 = dp_rest(D1) )
                    176:                if ( weight(D1) > Wmax )
                    177:                        Wmax = weight(D1);
                    178:        for ( D1 = D, Dmax = 0; D1; D1 = dp_rest(D1) )
                    179:                if ( weight(D1) == Wmax )
                    180:                        Dmax += dp_hm(D1);
                    181:        if ( Wmax >= 0 )
                    182:                Dmax = dp_weyl_mul(<<Wmax,0>>,Dmax);
                    183:        else
                    184:                Dmax = dp_weyl_mul(<<0,-Wmax>>,Dmax);
                    185:        Rmax = dp_dtop(Dmax,[T,DT]);
                    186:        R = b_subst(subst(Rmax,DT,1),T);
                    187:        return R;
                    188: }
                    189:
                    190: def weight(D)
                    191: {
                    192:        V = dp_etov(D);
                    193:        return V[1]-V[0];
                    194: }
                    195:
                    196: def compare_first(A,B)
                    197: {
                    198:        A0 = car(A);
                    199:        B0 = car(B);
                    200:        if ( A0 > B0 )
                    201:                return 1;
                    202:        else if ( A0 < B0 )
                    203:                return -1;
                    204:        else
                    205:                return 0;
                    206: }
                    207:
1.13      noro      208: /* generic b-function w.r.t. weight vector W */
                    209:
                    210: def generic_bfct(F,V,DV,W)
                    211: {
                    212:        N = length(V);
                    213:        N2 = N*2;
                    214:
1.16      noro      215:        /* If W is a list, convert it to a vector */
                    216:        if ( type(W) == 4 )
                    217:                W = newvect(length(W),W);
1.15      noro      218:        dp_weyl_set_weight(W);
                    219:
1.14      noro      220:        /* create a term order M in D<x,d> (DRL) */
1.13      noro      221:        M = newmat(N2,N2);
                    222:        for ( J = 0; J < N2; J++ )
                    223:                M[0][J] = 1;
                    224:        for ( I = 1; I < N2; I++ )
                    225:                M[I][N2-I] = -1;
                    226:
                    227:        VDV = append(V,DV);
                    228:
                    229:        /* create a non-term order MW in D<x,d> */
                    230:        MW = newmat(N2+1,N2);
                    231:        for ( J = 0; J < N; J++ )
                    232:                MW[0][J] = -W[J];
                    233:        for ( ; J < N2; J++ )
                    234:                MW[0][J] = W[J-N];
                    235:        for ( I = 1; I <= N2; I++ )
                    236:                for ( J = 0; J < N2; J++ )
                    237:                        MW[I][J] = M[I-1][J];
                    238:
                    239:        /* create a homogenized term order MWH in D<x,d,h> */
                    240:        MWH = newmat(N2+2,N2+1);
                    241:        for ( J = 0; J <= N2; J++ )
                    242:                MWH[0][J] = 1;
                    243:        for ( I = 1; I <= N2+1; I++ )
                    244:                for ( J = 0; J < N2; J++ )
                    245:                        MWH[I][J] = MW[I-1][J];
                    246:
                    247:        /* homogenize F */
                    248:        VDVH = append(VDV,[h]);
                    249:        FH = map(dp_dtop,map(dp_homo,map(dp_ptod,F,VDV)),VDVH);
                    250:
                    251:        /* compute a groebner basis of FH w.r.t. MWH */
1.15      noro      252:        dp_gr_flags(["Top",1,"NoRA",1]);
                    253:        GH = dp_weyl_gr_main(FH,VDVH,0,1,11);
                    254:        dp_gr_flags(["Top",0,"NoRA",0]);
1.13      noro      255:
                    256:        /* dehomigenize GH */
                    257:        G = map(subst,GH,h,1);
                    258:
                    259:        /* G is a groebner basis w.r.t. a non term order MW */
                    260:        /* take the initial part w.r.t. (-W,W) */
                    261:        GIN = map(initial_part,G,VDV,MW,W);
                    262:
                    263:        /* GIN is a groebner basis w.r.t. a term order M */
                    264:        /* As -W+W=0, gr_(-W,W)(D<x,d>) = D<x,d> */
                    265:
                    266:        /* find b(W1*x1*d1+...+WN*xN*dN) in Id(GIN) */
                    267:        for ( I = 0, T = 0; I < N; I++ )
                    268:                T += W[I]*V[I]*DV[I];
1.14      noro      269:        B = weyl_minipoly(GIN,VDV,0,T); /* M represents DRL order */
1.13      noro      270:        return B;
                    271: }
                    272:
1.18      noro      273: /* all term reduction + interreduce */
                    274: def generic_bfct_1(F,V,DV,W)
                    275: {
                    276:        N = length(V);
                    277:        N2 = N*2;
                    278:
                    279:        /* If W is a list, convert it to a vector */
                    280:        if ( type(W) == 4 )
                    281:                W = newvect(length(W),W);
                    282:        dp_weyl_set_weight(W);
                    283:
                    284:        /* create a term order M in D<x,d> (DRL) */
                    285:        M = newmat(N2,N2);
                    286:        for ( J = 0; J < N2; J++ )
                    287:                M[0][J] = 1;
                    288:        for ( I = 1; I < N2; I++ )
                    289:                M[I][N2-I] = -1;
                    290:
                    291:        VDV = append(V,DV);
                    292:
                    293:        /* create a non-term order MW in D<x,d> */
                    294:        MW = newmat(N2+1,N2);
                    295:        for ( J = 0; J < N; J++ )
                    296:                MW[0][J] = -W[J];
                    297:        for ( ; J < N2; J++ )
                    298:                MW[0][J] = W[J-N];
                    299:        for ( I = 1; I <= N2; I++ )
                    300:                for ( J = 0; J < N2; J++ )
                    301:                        MW[I][J] = M[I-1][J];
                    302:
                    303:        /* create a homogenized term order MWH in D<x,d,h> */
                    304:        MWH = newmat(N2+2,N2+1);
                    305:        for ( J = 0; J <= N2; J++ )
                    306:                MWH[0][J] = 1;
                    307:        for ( I = 1; I <= N2+1; I++ )
                    308:                for ( J = 0; J < N2; J++ )
                    309:                        MWH[I][J] = MW[I-1][J];
                    310:
                    311:        /* homogenize F */
                    312:        VDVH = append(VDV,[h]);
                    313:        FH = map(dp_dtop,map(dp_homo,map(dp_ptod,F,VDV)),VDVH);
                    314:
                    315:        /* compute a groebner basis of FH w.r.t. MWH */
                    316: /*     dp_gr_flags(["Top",1,"NoRA",1]); */
                    317:        GH = dp_weyl_gr_main(FH,VDVH,0,1,11);
                    318: /*     dp_gr_flags(["Top",0,"NoRA",0]); */
                    319:
                    320:        /* dehomigenize GH */
                    321:        G = map(subst,GH,h,1);
                    322:
                    323:        /* G is a groebner basis w.r.t. a non term order MW */
                    324:        /* take the initial part w.r.t. (-W,W) */
                    325:        GIN = map(initial_part,G,VDV,MW,W);
                    326:
                    327:        /* GIN is a groebner basis w.r.t. a term order M */
                    328:        /* As -W+W=0, gr_(-W,W)(D<x,d>) = D<x,d> */
                    329:
                    330:        /* find b(W1*x1*d1+...+WN*xN*dN) in Id(GIN) */
                    331:        for ( I = 0, T = 0; I < N; I++ )
                    332:                T += W[I]*V[I]*DV[I];
                    333:        B = weyl_minipoly(GIN,VDV,0,T); /* M represents DRL order */
                    334:        return B;
                    335: }
                    336:
1.13      noro      337: def initial_part(F,V,MW,W)
                    338: {
                    339:        N2 = length(V);
                    340:        N = N2/2;
                    341:        dp_ord(MW);
                    342:        DF = dp_ptod(F,V);
                    343:        R = dp_hm(DF);
                    344:        DF = dp_rest(DF);
                    345:
                    346:        E = dp_etov(R);
                    347:        for ( I = 0, TW = 0; I < N; I++ )
                    348:                TW += W[I]*(-E[I]+E[N+I]);
                    349:        RW = TW;
                    350:
                    351:        for ( ; DF; DF = dp_rest(DF) ) {
                    352:                E = dp_etov(DF);
                    353:                for ( I = 0, TW = 0; I < N; I++ )
                    354:                        TW += W[I]*(-E[I]+E[N+I]);
                    355:                if ( TW == RW )
                    356:                        R += dp_hm(DF);
                    357:                else if ( TW < RW )
                    358:                        break;
                    359:                else
                    360:                        error("initial_part : cannot happen");
                    361:        }
                    362:        return dp_dtop(R,V);
                    363:
                    364: }
                    365:
1.1       noro      366: /* b-function of F ? */
                    367:
                    368: def bfct(F)
                    369: {
                    370:        V = vars(F);
                    371:        N = length(V);
1.6       noro      372:        D = newvect(N);
1.7       noro      373:
1.6       noro      374:        for ( I = 0; I < N; I++ )
                    375:                D[I] = [deg(F,V[I]),V[I]];
                    376:        qsort(D,compare_first);
                    377:        for ( V = [], I = 0; I < N; I++ )
                    378:                V = cons(D[I][1],V);
1.1       noro      379:        for ( I = N-1, DV = []; I >= 0; I-- )
                    380:                DV = cons(strtov("d"+rtostr(V[I])),DV);
1.6       noro      381:        V1 = cons(s,V); DV1 = cons(ds,DV);
1.7       noro      382:
                    383:        G0 = indicial1(F,reverse(V));
                    384:        G1 = dp_weyl_gr_main(G0,append(V1,DV1),0,1,0);
                    385:        Minipoly = weyl_minipoly(G1,append(V1,DV1),0,s);
1.6       noro      386:        return Minipoly;
                    387: }
                    388:
1.14      noro      389: /* b-function computation via generic_bfct() (experimental) */
                    390:
                    391: def bfct_via_gbfct(F)
                    392: {
                    393:        V = vars(F);
                    394:        N = length(V);
                    395:        D = newvect(N);
                    396:
                    397:        for ( I = 0; I < N; I++ )
                    398:                D[I] = [deg(F,V[I]),V[I]];
                    399:        qsort(D,compare_first);
                    400:        for ( V = [], I = 0; I < N; I++ )
                    401:                V = cons(D[I][1],V);
                    402:        V = reverse(V);
                    403:        for ( I = N-1, DV = []; I >= 0; I-- )
                    404:                DV = cons(strtov("d"+rtostr(V[I])),DV);
                    405:
                    406:        B = [t-F];
                    407:        for ( I = 0; I < N; I++ ) {
                    408:                B = cons(DV[I]+diff(F,V[I])*dt,B);
                    409:        }
                    410:        V1 = cons(t,V); DV1 = cons(dt,DV);
                    411:        W = newvect(N+1);
                    412:        W[0] = 1;
1.18      noro      413:        R = generic_bfct_1(B,V1,DV1,W);
1.14      noro      414:
                    415:        return subst(R,s,-s-1);
                    416: }
                    417:
1.17      noro      418: /* use an order s.t. [t,x,y,z,...,dt,dx,dy,dz,...,h] */
                    419:
                    420: def bfct_via_gbfct_weight(F,V)
                    421: {
                    422:        N = length(V);
                    423:        D = newvect(N);
                    424:        Wt = getopt(weight);
1.18      noro      425:        if ( type(Wt) != 4 ) {
                    426:                for ( I = 0, Wt = []; I < N; I++ )
                    427:                        Wt = cons(1,Wt);
                    428:        }
                    429:        Tdeg = w_tdeg(F,V,Wt);
                    430:        WtV = newvect(2*(N+1)+1);
                    431:        WtV[0] = Tdeg;
                    432:        WtV[N+1] = 1;
                    433:        /* wdeg(V[I])=Wt[I], wdeg(DV[I])=Tdeg-Wt[I]+1 */
                    434:        for ( I = 1; I <= N; I++ ) {
                    435:                WtV[I] = Wt[I-1];
                    436:                WtV[N+1+I] = Tdeg-Wt[I-1]+1;
1.17      noro      437:        }
1.18      noro      438:        WtV[2*(N+1)] = 1;
                    439:        dp_set_weight(WtV);
1.17      noro      440:        for ( I = N-1, DV = []; I >= 0; I-- )
                    441:                DV = cons(strtov("d"+rtostr(V[I])),DV);
                    442:
                    443:        B = [t-F];
                    444:        for ( I = 0; I < N; I++ ) {
                    445:                B = cons(DV[I]+diff(F,V[I])*dt,B);
                    446:        }
                    447:        V1 = cons(t,V); DV1 = cons(dt,DV);
                    448:        W = newvect(N+1);
                    449:        W[0] = 1;
1.18      noro      450:        R = generic_bfct_1(B,V1,DV1,W);
                    451:        dp_set_weight(0);
1.17      noro      452:        return subst(R,s,-s-1);
                    453: }
                    454:
                    455: /* use an order s.t. [x,y,z,...,t,dx,dy,dz,...,dt,h] */
                    456:
                    457: def bfct_via_gbfct_weight_1(F,V)
                    458: {
                    459:        N = length(V);
                    460:        D = newvect(N);
                    461:        Wt = getopt(weight);
1.18      noro      462:        if ( type(Wt) != 4 ) {
                    463:                for ( I = 0, Wt = []; I < N; I++ )
                    464:                        Wt = cons(1,Wt);
                    465:        }
                    466:        Tdeg = w_tdeg(F,V,Wt);
                    467:        WtV = newvect(2*(N+1)+1);
                    468:        /* wdeg(V[I])=Wt[I], wdeg(DV[I])=Tdeg-Wt[I]+1 */
                    469:        for ( I = 0; I < N; I++ ) {
                    470:                WtV[I] = Wt[I];
                    471:                WtV[N+1+I] = Tdeg-Wt[I]+1;
1.17      noro      472:        }
1.18      noro      473:        WtV[N] = Tdeg;
                    474:        WtV[2*N+1] = 1;
                    475:        WtV[2*(N+1)] = 1;
                    476:        dp_set_weight(WtV);
1.17      noro      477:        for ( I = N-1, DV = []; I >= 0; I-- )
                    478:                DV = cons(strtov("d"+rtostr(V[I])),DV);
                    479:
                    480:        B = [t-F];
                    481:        for ( I = 0; I < N; I++ ) {
                    482:                B = cons(DV[I]+diff(F,V[I])*dt,B);
                    483:        }
                    484:        V1 = append(V,[t]); DV1 = append(DV,[dt]);
                    485:        W = newvect(N+1);
                    486:        W[N] = 1;
                    487:        R = generic_bfct(B,V1,DV1,W);
1.19    ! noro      488:        dp_set_weight(0);
        !           489:        return subst(R,s,-s-1);
        !           490: }
        !           491:
        !           492: def bfct_via_gbfct_weight_2(F,V)
        !           493: {
        !           494:        N = length(V);
        !           495:        D = newvect(N);
        !           496:        Wt = getopt(weight);
        !           497:        if ( type(Wt) != 4 ) {
        !           498:                for ( I = 0, Wt = []; I < N; I++ )
        !           499:                        Wt = cons(1,Wt);
        !           500:        }
        !           501:        Tdeg = w_tdeg(F,V,Wt);
        !           502:
        !           503:        /* a weight for the first GB computation */
        !           504:        /* [t,x1,...,xn,dt,dx1,...,dxn,h] */
        !           505:        WtV = newvect(2*(N+1)+1);
        !           506:        WtV[0] = Tdeg;
        !           507:        WtV[N+1] = 1;
        !           508:        WtV[2*(N+1)] = 1;
        !           509:        /* wdeg(V[I])=Wt[I], wdeg(DV[I])=Tdeg-Wt[I]+1 */
        !           510:        for ( I = 1; I <= N; I++ ) {
        !           511:                WtV[I] = Wt[I-1];
        !           512:                WtV[N+1+I] = Tdeg-Wt[I-1]+1;
        !           513:        }
        !           514:        dp_set_weight(WtV);
        !           515:
        !           516:        /* a weight for the second GB computation */
        !           517:        /* [x1,...,xn,t,dx1,...,dxn,dt,h] */
        !           518:        WtV2 = newvect(2*(N+1)+1);
        !           519:        WtV2[N] = Tdeg;
        !           520:        WtV2[2*N+1] = 1;
        !           521:        WtV2[2*(N+1)] = 1;
        !           522:        for ( I = 0; I < N; I++ ) {
        !           523:                WtV2[I] = Wt[I];
        !           524:                WtV2[N+1+I] = Tdeg-Wt[I]+1;
        !           525:        }
        !           526:
        !           527:        for ( I = N-1, DV = []; I >= 0; I-- )
        !           528:                DV = cons(strtov("d"+rtostr(V[I])),DV);
        !           529:
        !           530:        B = [t-F];
        !           531:        for ( I = 0; I < N; I++ ) {
        !           532:                B = cons(DV[I]+diff(F,V[I])*dt,B);
        !           533:        }
        !           534:        V1 = cons(t,V); DV1 = cons(dt,DV);
        !           535:        V2 = append(V,[t]); DV2 = append(DV,[dt]);
        !           536:        W = newvect(N+1,[1]);
        !           537:        dp_weyl_set_weight(W);
        !           538:
        !           539:        VDV = append(V1,DV1);
        !           540:        N1 = length(V1);
        !           541:        N2 = N1*2;
        !           542:
        !           543:        /* create a non-term order MW in D<x,d> */
        !           544:        MW = newmat(N2+1,N2);
        !           545:        for ( J = 0; J < N1; J++ ) {
        !           546:                MW[0][J] = -W[J]; MW[0][N1+J] = W[J];
        !           547:        }
        !           548:        for ( J = 0; J < N2; J++ ) MW[1][J] = 1;
        !           549:        for ( I = 2; I <= N2; I++ ) MW[I][N2-I+1] = -1;
        !           550:
        !           551:        /* homogenize F */
        !           552:        VDVH = append(VDV,[h]);
        !           553:        FH = map(dp_dtop,map(dp_homo,map(dp_ptod,B,VDV)),VDVH);
        !           554:
        !           555:        /* compute a groebner basis of FH w.r.t. MWH */
        !           556:        GH = dp_weyl_gr_main(FH,VDVH,0,1,11);
        !           557:
        !           558:        /* dehomigenize GH */
        !           559:        G = map(subst,GH,h,1);
        !           560:
        !           561:        /* G is a groebner basis w.r.t. a non term order MW */
        !           562:        /* take the initial part w.r.t. (-W,W) */
        !           563:        GIN = map(initial_part,G,VDV,MW,W);
        !           564:
        !           565:        /* GIN is a groebner basis w.r.t. a term order M */
        !           566:        /* As -W+W=0, gr_(-W,W)(D<x,d>) = D<x,d> */
        !           567:
        !           568:        /* find b(W1*x1*d1+...+WN*xN*dN) in Id(GIN) */
        !           569:        for ( I = 0, T = 0; I < N1; I++ )
        !           570:                T += W[I]*V1[I]*DV1[I];
        !           571:
        !           572:        /* change of ordering from VDV to VDV2 */
        !           573:        VDV2 = append(V2,DV2);
        !           574:        dp_set_weight(WtV2);
        !           575:        GIN2 = dp_weyl_gr_main(GIN,VDV2,0,-1,0);
        !           576:
        !           577:        R = weyl_minipoly(GIN2,VDV2,0,T); /* M represents DRL order */
1.18      noro      578:        dp_set_weight(0);
1.17      noro      579:        return subst(R,s,-s-1);
                    580: }
                    581:
1.6       noro      582: def weyl_minipolym(G,V,O,M,V0)
                    583: {
                    584:        N = length(V);
                    585:        Len = length(G);
                    586:        dp_ord(O);
                    587:        setmod(M);
                    588:        PS = newvect(Len);
                    589:        PS0 = newvect(Len);
                    590:
                    591:        for ( I = 0, T = G; T != []; T = cdr(T), I++ )
                    592:                PS0[I] = dp_ptod(car(T),V);
                    593:        for ( I = 0, T = G; T != []; T = cdr(T), I++ )
                    594:                PS[I] = dp_mod(dp_ptod(car(T),V),M,[]);
                    595:
                    596:        for ( I = Len - 1, GI = []; I >= 0; I-- )
                    597:                GI = cons(I,GI);
                    598:
                    599:        U = dp_mod(dp_ptod(V0,V),M,[]);
1.17      noro      600:        U = dp_weyl_nf_mod(GI,U,PS,1,M);
1.6       noro      601:
                    602:        T = dp_mod(<<0>>,M,[]);
                    603:        TT = dp_mod(dp_ptod(1,V),M,[]);
                    604:        G = H = [[TT,T]];
                    605:
                    606:        for ( I = 1; ; I++ ) {
1.14      noro      607:                if ( dp_gr_print() )
                    608:                        print(".",2);
1.6       noro      609:                T = dp_mod(<<I>>,M,[]);
                    610:
                    611:                TT = dp_weyl_nf_mod(GI,dp_weyl_mul_mod(TT,U,M),PS,1,M);
                    612:                H = cons([TT,T],H);
                    613:                L = dp_lnf_mod([TT,T],G,M);
1.14      noro      614:                if ( !L[0] ) {
                    615:                        if ( dp_gr_print() )
                    616:                                print("");
1.13      noro      617:                        return dp_dtop(L[1],[t]); /* XXX */
1.14      noro      618:                } else
1.6       noro      619:                        G = insert(G,L);
                    620:        }
                    621: }
                    622:
1.13      noro      623: def weyl_minipoly(G0,V0,O0,P)
1.6       noro      624: {
1.11      noro      625:        HM = hmlist(G0,V0,O0);
1.13      noro      626:
                    627:        N = length(V0);
                    628:        Len = length(G0);
                    629:        dp_ord(O0);
                    630:        PS = newvect(Len);
                    631:        for ( I = 0, T = G0, HL = []; T != []; T = cdr(T), I++ )
                    632:                PS[I] = dp_ptod(car(T),V0);
                    633:        for ( I = Len - 1, GI = []; I >= 0; I-- )
                    634:                GI = cons(I,GI);
                    635:        DP = dp_ptod(P,V0);
                    636:
1.6       noro      637:        for ( I = 0; ; I++ ) {
                    638:                Prime = lprime(I);
1.11      noro      639:                if ( !valid_modulus(HM,Prime) )
                    640:                        continue;
1.13      noro      641:                MP = weyl_minipolym(G0,V0,O0,Prime,P);
                    642:                D = deg(MP,var(MP));
                    643:
                    644:                NFP = weyl_nf(GI,DP,1,PS);
                    645:                NF = [[dp_ptod(1,V0),1]];
                    646:                LCM = 1;
                    647:
                    648:                for ( J = 1; J <= D; J++ ) {
1.14      noro      649:                        if ( dp_gr_print() )
                    650:                                print(".",2);
1.13      noro      651:                        NFPrev = car(NF);
                    652:                        NFJ = weyl_nf(GI,
                    653:                                dp_weyl_mul(NFP[0],NFPrev[0]),NFP[1]*NFPrev[1],PS);
                    654:                        NFJ = remove_cont(NFJ);
                    655:                        NF = cons(NFJ,NF);
                    656:                        LCM = ilcm(LCM,NFJ[1]);
                    657:                }
1.14      noro      658:                if ( dp_gr_print() )
                    659:                        print("");
1.13      noro      660:                U = NF[0][0]*idiv(LCM,NF[0][1]);
                    661:                Coef = [];
                    662:                for ( J = D-1; J >= 0; J-- ) {
                    663:                        Coef = cons(strtov("u"+rtostr(J)),Coef);
                    664:                        U += car(Coef)*NF[D-J][0]*idiv(LCM,NF[D-J][1]);
                    665:                }
1.6       noro      666:
1.13      noro      667:                for ( UU = U, Eq = []; UU; UU = dp_rest(UU) )
                    668:                        Eq = cons(dp_hc(UU),Eq);
                    669:                M = etom([Eq,Coef]);
                    670:                B = henleq(M,Prime);
                    671:                if ( dp_gr_print() )
                    672:                        print("");
1.6       noro      673:                if ( B ) {
1.13      noro      674:                        R = 0;
                    675:                        for ( I = 0; I < D; I++ )
                    676:                                R += B[0][I]*s^I;
                    677:                        R += B[1]*s^D;
1.6       noro      678:                        return R;
                    679:                }
                    680:        }
                    681: }
                    682:
                    683: def weyl_nf(B,G,M,PS)
                    684: {
                    685:        for ( D = 0; G; ) {
                    686:                for ( U = 0, L = B; L != []; L = cdr(L) ) {
                    687:                        if ( dp_redble(G,R=PS[car(L)]) > 0 ) {
                    688:                                GCD = igcd(dp_hc(G),dp_hc(R));
                    689:                                CG = idiv(dp_hc(R),GCD); CR = idiv(dp_hc(G),GCD);
                    690:                                U = CG*G-dp_weyl_mul(CR*dp_subd(G,R),R);
                    691:                                if ( !U )
                    692:                                        return [D,M];
                    693:                                D *= CG; M *= CG;
                    694:                                break;
                    695:                        }
                    696:                }
                    697:                if ( U )
                    698:                        G = U;
                    699:                else {
                    700:                        D += dp_hm(G); G = dp_rest(G);
                    701:                }
                    702:        }
                    703:        return [D,M];
                    704: }
                    705:
                    706: def weyl_nf_mod(B,G,PS,Mod)
                    707: {
                    708:        for ( D = 0; G; ) {
                    709:                for ( U = 0, L = B; L != []; L = cdr(L) ) {
                    710:                        if ( dp_redble(G,R=PS[car(L)]) > 0 ) {
                    711:                                CR = dp_hc(G)/dp_hc(R);
                    712:                                U = G-dp_weyl_mul_mod(CR*dp_mod(dp_subd(G,R),Mod,[]),R,Mod);
                    713:                                if ( !U )
                    714:                                        return D;
1.1       noro      715:                                break;
1.6       noro      716:                        }
                    717:                }
                    718:                if ( U )
                    719:                        G = U;
                    720:                else {
                    721:                        D += dp_hm(G); G = dp_rest(G);
1.1       noro      722:                }
                    723:        }
1.6       noro      724:        return D;
1.1       noro      725: }
                    726:
                    727: def remove_zero(L)
                    728: {
                    729:        for ( R = []; L != []; L = cdr(L) )
                    730:                if ( car(L) )
                    731:                        R = cons(car(L),R);
                    732:        return R;
                    733: }
                    734:
                    735: def z_subst(F,V)
                    736: {
                    737:        for ( ; V != []; V = cdr(V) )
                    738:                F = subst(F,car(V),0);
                    739:        return F;
                    740: }
                    741:
                    742: def flatmf(L) {
                    743:     for ( S = []; L != []; L = cdr(L) )
                    744:                if ( type(F=car(car(L))) != NUM )
                    745:                        S = append(S,[F]);
                    746:        return S;
                    747: }
                    748:
                    749: def member(A,L) {
                    750:     for ( ; L != []; L = cdr(L) )
                    751:                if ( A == car(L) )
                    752:                        return 1;
                    753:        return 0;
                    754: }
                    755:
                    756: def intersection(A,B)
                    757: {
                    758:        for ( L = []; A != []; A = cdr(A) )
                    759:        if ( member(car(A),B) )
                    760:                L = cons(car(A),L);
                    761:        return L;
                    762: }
                    763:
                    764: def b_subst(F,V)
                    765: {
                    766:        D = deg(F,V);
                    767:        C = newvect(D+1);
                    768:        for ( I = D; I >= 0; I-- )
                    769:                C[I] = coef(F,I,V);
                    770:        for ( I = 0, R = 0; I <= D; I++ )
                    771:                if ( C[I] )
                    772:                        R += C[I]*v_factorial(V,I);
                    773:        return R;
                    774: }
                    775:
                    776: def v_factorial(V,N)
                    777: {
                    778:        for ( J = N-1, R = 1; J >= 0; J-- )
                    779:                R *= V-J;
1.17      noro      780:        return R;
                    781: }
                    782:
                    783: def w_tdeg(F,V,W)
                    784: {
                    785:        dp_set_weight(newvect(length(W),W));
                    786:        T = dp_ptod(F,V);
                    787:        for ( R = 0; T; T = cdr(T) ) {
                    788:                D = dp_td(T);
                    789:                if ( D > R ) R = D;
                    790:        }
1.1       noro      791:        return R;
                    792: }
                    793: end$
                    794:

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