STATICInt GREASEPOS_INT(Obj v, Int p, Int d, Int *pivs, Int pivslen)
{ Int i,j;
seqaccess sa; Int res;
Word *ww = DATA_CVEC(v);
i = pivslen-1;
INIT_SEQ_ACCESS(&sa,v,pivs[i]);
res = 0; while (1) { /* we use break */ /* sa already points to position i! */ for (j = d-1;j >= 0;j--) res = res * p + GET_VEC_ELM(&sa,ww,j); if (--i < 0) break;
MOVE_SEQ_ACCESS(&sa,pivs[i]);
} return res+1;
}
STATICInt GREASEPOS_INT_WITH_DEC(Obj v, Int p, Int d, Int *pivs, Int pivslen,
Obj dec, Int startpos)
{ Int i,j;
seqaccess sa;
seqaccess sadec; Int res;
Word *ww = DATA_CVEC(v);
Word *dd = DATA_CVEC(dec); Int c;
i = pivslen-1;
INIT_SEQ_ACCESS(&sa,v,pivs[i]);
INIT_SEQ_ACCESS(&sadec,dec,startpos+pivslen-1);
res = 0; while (1) { /* we use break */ /* sa already points to position i! */ for (j = d-1;j >= 0;j--) {
c = GET_VEC_ELM(&sa,ww,j);
res = res * p + c;
SET_VEC_ELM(&sadec,dd,j,c);
} if (--i < 0) break;
MOVE_SEQ_ACCESS(&sa,pivs[i]);
STEP_LEFT(&sadec);
} return res+1;
}
STATIC Obj GetLinearCombination(Obj self, Obj lg_vecs, Obj lg_tab, Obj lg_ind, Int lg_lev, Obj vec, Obj cl, Obj fi, Int p, Int d, Int offset, Int *pivs, Int pivslen, Int len, Obj dec, Int wordlen)
{ /* This function may trigger GARBAGE COLLECTIONS! */ Int pos; Int group; Int i;
Obj w;
Obj ourtab;
Obj rows = ElmPRec( lg_tab, RNamName("rows") ); Int tlen;
/* offset must be congruent 1 mod lev */ if (dec != False && dec != True && pivslen == lg_lev)
pos = GREASEPOS_INT_WITH_DEC(vec,p,d,pivs,pivslen,dec,offset); else
pos = GREASEPOS_INT(vec,p,d,pivs,pivslen); if (pos == 1) return INTOBJ_INT(0L);
group = (offset-1) / lg_lev + 1; /* if (LEN_PLIST(lg_ind) < group || ELM_PLIST(lg_ind,group) == 0L) {*/ if (!ISB_LIST(lg_ind,group)) {
ASS_LIST(lg_ind,group,NEW_PLIST(T_PLIST,pos));
} /* GARBAGE COLLECTION POSSIBLE! */
ourtab = ELM_PLIST(lg_ind,group); if (!ISB_LIST(ourtab,pos)) { /* First we need a new vector: */
w = NEW(self,cl,ELM_PLIST(cl,IDX_type)); /* GARBAGE COLLECTION POSSIBLE! */ if (d == 1) { /* We distinguish prime field and extension field: */ /* Cut away all trailing zeroes: */ Int c; /* Note that at least one position is nonzero, otherwise pos==1 */
i = pivslen-1; while (1) {
c = CVEC_Itemp(fi, DATA_CVEC(vec), pivs[i]); if (c) break;
i--;
} /* Again: i < 0 does not happen! */
MUL2_INL(DATA_CVEC(w),DATA_CVEC(ELM_PLIST(lg_vecs,offset+i+1)),fi,
c,wordlen); if (i > 0) {
Obj ww;
ww = GetLinearCombination(self,lg_vecs,lg_tab,lg_ind,lg_lev,
vec,cl,fi,p,d,offset,pivs,i,len,dec,wordlen); if (ww != INTOBJ_INT(0))
ADD2_INL(DATA_CVEC(w),DATA_CVEC(ww),fi,wordlen);
}
tlen = LEN_LIST(rows);
ASS_LIST(rows,tlen+1,w);
AssPRec(lg_tab,RNamName("len"),INTOBJ_INT(tlen)); /* Note the fail in position 1! */
ASS_LIST(ourtab,pos,INTOBJ_INT(tlen)); /* shift intentional because of the fail in position 1 of rows! */ return w;
} else { /* extension field case: */ /* Cut away all trailing zeroes: */ /* Note that at least one position is nonzero, otherwise pos==1 */
i = pivslen-1; while (1) {
CVEC_Itemq(fi, DATA_CVEC(vec), pivs[i]); if (sclen > 1 || scbuf[0] != 0) break;
i--;
} /* Again: i < 0 does not happen! */
MUL2_INT(w,cl,fi,ELM_PLIST(lg_vecs,offset+i+1),d,wordlen,scbuf); if (i > 0) {
Obj ww;
ww = GetLinearCombination(self,lg_vecs,lg_tab,lg_ind,lg_lev,
vec,cl,fi,p,d,offset,pivs,i,len,dec,wordlen); if (ww != INTOBJ_INT(0))
ADD2_INL(DATA_CVEC(w),DATA_CVEC(ww),fi,wordlen);
}
tlen = LEN_LIST(rows);
ASS_LIST(rows,tlen+1,w);
AssPRec(lg_tab,RNamName("len"),INTOBJ_INT(tlen)); /* Note the fail in position 1! */
ASS_LIST(ourtab,pos,INTOBJ_INT(tlen)); /* shift intentional because of the fail in position 1 of rows! */ return w;
}
} else { return ELM_PLIST(rows,INT_INTOBJ(ELM_PLIST(ourtab,pos))+1); /* Note the fail in position 1 of lg_tab */
}
}
/* Aus CleanRowKernel: */
Obj lazygreaser = ElmPRec( basis, RNamName( "lazygreaser" ) ); Int pivs[16]; /* we will never see more than level 10 grease or so */
Obj lc; Int shortcut;
if (lazygreaser != Fail) { /* The grease case: */
Obj lg_tab = ElmPRec( lazygreaser, RNamName( "tab" ) );
Obj lg_ind = ElmPRec( lazygreaser, RNamName( "ind" ) ); Int lg_lev = INT_INTOBJ(ElmPRec( lazygreaser, RNamName( "lev" ) ) ); /* Note that lazygrease!.vecs must be the same object as
* basis.vectors! */
for (i = 1;i+lg_lev-1 <= len;i += lg_lev) { /* Fetch the columns to work on: */
shortcut = 1; for (j = 0;j < lg_lev;j++) {
pivs[j] = INT_INTOBJ(ELM_PLIST(pivots,i+j)); if (pivs[j] >= firstnz) shortcut = 0;
} if (!shortcut) { /* Otherwise, there is nothing to do at all */ Int lll = INT_INTOBJ(ElmPRec(lazygreaser,RNamName("count"))); for (; lll > 0;lll--)
lc = GetLinearCombination(self,rows,lg_tab,lg_ind,lg_lev,vec,
cl,fi,p,d,i,pivs,lg_lev,len,dec,wordlen); /* This changes dec in positions i..i+lg_lev-1 if it is a cvec! */ if (lc != INTOBJ_INT(0L)) /* 0 indicates the zero linear combination */
ADDMUL_INL( DATA_CVEC(vec), DATA_CVEC(lc),fi,p-1,wordlen );
}
} /* Now go to the standard case for the rest, starting at i */
} else i = 1; /* The non-grease case starts from the beginning */
/* we have to work without the lazy greaser: */
...
if (lazygreaser != Fail) { /* In the grease case, we do full-echelon form within the
grease block: */ for (j = i;j <= len;j++) {
Word *w = DATA_CVEC(ELM_PLIST(rows,j+1));
c = CVEC_Itemp(fi,w,newpiv); if (c) ADDMUL_INL(w,vecvec,fi,p-c,wordlen);
}
}
...
if (lazygreaser != Fail) { /* In the grease case, we do full-echelon form within the
grease block: */ for (j = i;j <= len;j++) {
Obj w = ELM_PLIST(rows,j+1);
CVEC_Itemq(fi,DATA_CVEC(w),newpiv); if (sclen > 1 || scbuf[0] != 0) { Int k; for (k = sclen-1;k >= 0;k--)
scbuf[k] = scbuf[k] ? p-scbuf[k] : 0;
ADDMUL_INT(w,cl,fi,vec,d,scbuf,0,wordlen);
}
}
}
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