| 1 | /**************************************** |
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| 2 | * Computer Algebra System SINGULAR * |
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| 3 | ****************************************/ |
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| 4 | /* $Id: khstd.cc,v 1.8 1998-12-15 10:06:47 pohl Exp $ */ |
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| 5 | /* |
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| 6 | * ABSTRACT:utils for hilbert driven kStd |
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| 7 | */ |
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| 8 | |
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| 9 | #include "mod2.h" |
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| 10 | #include "tok.h" |
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| 11 | #include "febase.h" |
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| 12 | #include "polys.h" |
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| 13 | #include "intvec.h" |
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| 14 | #include "kutil.h" |
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| 15 | #include "stairc.h" |
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| 16 | #include "kstd1.h" |
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| 17 | #include "khstd.h" |
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| 18 | |
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| 19 | /*2 |
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| 20 | * compare the given hilbert series with the current one, |
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| 21 | * delete not needed pairs (if possible) |
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| 22 | */ |
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| 23 | void khCheck( ideal Q, intvec *w, intvec *hilb, int &eledeg, int &count, |
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| 24 | kStrategy strat) |
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| 25 | /* ideal S=strat->Shdl, poly p=strat->P.p */ |
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| 26 | /* |
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| 27 | * compute the number eledeg of elements with a degree >= deg(p) going into kStd, |
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| 28 | * p is already in S and for all further q going into S yields deg(q) >= deg(p), |
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| 29 | * the real computation is only done if the degree has changed, |
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| 30 | * then we have eledeg == 0 on this degree and we make: |
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| 31 | * - compute the Hilbert series newhilb from S |
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| 32 | * (hilb is the final Hilbert series) |
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| 33 | * - compute the eledeg from newhilb-hilb for the first degree deg with |
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| 34 | * newhilb-hilb != 0 |
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| 35 | * (Remark: consider the Hilbert series with coeff. up to infinity) |
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| 36 | * - clear the set L for degree < deg |
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| 37 | * the number count is only for statistics (in the caller initialise count = 0), |
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| 38 | * in order to get a first computation, initialise eledeg = 1 in the caller. |
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| 39 | * The weights w are needed in the module case, otherwise NULL. |
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| 40 | */ |
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| 41 | { |
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| 42 | intvec *newhilb; |
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| 43 | int deg,l,ln,mw; |
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| 44 | pFDegProc degp; |
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| 45 | |
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| 46 | eledeg--; |
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| 47 | if (eledeg == 0) |
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| 48 | { |
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| 49 | degp=pFDeg; |
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| 50 | if ((degp!=kModDeg) && (degp!=kHomModDeg)) degp=pWDegree; |
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| 51 | l = hilb->length()-1; |
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| 52 | mw = (*hilb)[l]; |
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| 53 | newhilb = hHstdSeries(strat->Shdl,w,strat->kHomW,Q); |
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| 54 | ln = newhilb->length()-1; |
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| 55 | deg = degp(strat->P.p)-mw; |
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| 56 | loop // compare the series in degree deg, try to increase deg ----------- |
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| 57 | { |
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| 58 | if (deg < ln) // deg may be out of range |
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| 59 | { |
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| 60 | if (deg < l) |
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| 61 | eledeg = (*newhilb)[deg]-(*hilb)[deg]; |
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| 62 | else |
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| 63 | eledeg = (*newhilb)[deg]; |
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| 64 | } |
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| 65 | else |
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| 66 | { |
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| 67 | if (deg < l) |
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| 68 | eledeg = -(*hilb)[deg]; |
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| 69 | else // we have newhilb = hilb |
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| 70 | { |
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| 71 | while (strat->Ll>=0) |
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| 72 | { |
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| 73 | count++; |
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| 74 | if(TEST_OPT_PROT) |
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| 75 | { |
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| 76 | PrintS("h"); |
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| 77 | mflush(); |
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| 78 | } |
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| 79 | deleteInL(strat->L,&strat->Ll,strat->Ll,strat); |
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| 80 | } |
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| 81 | return; |
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| 82 | } |
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| 83 | } |
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| 84 | if (eledeg != 0) |
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| 85 | break; |
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| 86 | deg++; |
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| 87 | } /* loop */ |
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| 88 | delete newhilb; |
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| 89 | while ((strat->Ll>=0) && (degp(strat->L[strat->Ll].p)-mw < deg)) // the essential step |
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| 90 | { |
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| 91 | count++; |
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| 92 | if(TEST_OPT_PROT) |
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| 93 | { |
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| 94 | PrintS("h"); |
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| 95 | mflush(); |
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| 96 | } |
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| 97 | deleteInL(strat->L,&strat->Ll,strat->Ll,strat); |
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| 98 | } |
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| 99 | } |
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| 100 | } |
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