| 1 | /**************************************** |
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| 2 | * Computer Algebra System SINGULAR * |
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| 3 | ****************************************/ |
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| 4 | /*************************************************************** |
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| 5 | * File: p_Add_q__Template.cc |
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| 6 | * Purpose: template for p_Add_q |
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| 7 | * Author: obachman (Olaf Bachmann) |
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| 8 | * Created: 8/00 |
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| 9 | * Version: $Id: p_Add_q__Template.cc,v 1.2 2000-09-12 16:01:05 obachman Exp $ |
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| 10 | *******************************************************************/ |
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| 11 | |
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| 12 | /*************************************************************** |
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| 13 | * |
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| 14 | * Returns: p + q, |
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| 15 | * Shorter, where Shorter == Length(p) + Length(q) - Length(p+q); |
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| 16 | * Destroys: p, q |
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| 17 | * |
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| 18 | ***************************************************************/ |
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| 19 | poly p_Add_q(poly p, poly q, int &Shorter, const ring r) |
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| 20 | { |
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| 21 | pTest(p); |
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| 22 | pTest(q); |
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| 23 | #ifdef PDEBUG |
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| 24 | int l = pLength(p) + pLength(q); |
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| 25 | #endif |
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| 26 | |
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| 27 | // test for trivial cases |
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| 28 | Shorter = 0; |
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| 29 | if (q == NULL) return p; |
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| 30 | if (p == NULL) return q; |
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| 31 | |
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| 32 | number t, n1, n2; |
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| 33 | int shorter = 0; |
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| 34 | spolyrec rp; |
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| 35 | poly a = &rp; |
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| 36 | DECLARE_LENGTH(const unsigned long length = r->pCompLSize); |
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| 37 | DECLARE_ORDSGN(const long* ordsgn = r->ordsgn); |
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| 38 | |
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| 39 | Top: // compare p and q w.r.t. monomial ordering |
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| 40 | p_MemCmp(p->exp, q->exp, length, ordsgn, goto Equal, goto Greater , goto Smaller ); |
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| 41 | |
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| 42 | Equal: |
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| 43 | n1 = pGetCoeff(p); |
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| 44 | n2 = pGetCoeff(q); |
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| 45 | t = p_nAdd(n1,n2, r); |
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| 46 | p_nDelete(&n1, r); |
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| 47 | p_nDelete(&n2, r); |
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| 48 | FreeAndAdvance(q); |
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| 49 | |
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| 50 | if (p_nIsZero(t, r)) |
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| 51 | { |
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| 52 | shorter += 2; |
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| 53 | p_nDelete(&t, r); |
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| 54 | FreeAndAdvance(p); |
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| 55 | } |
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| 56 | else |
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| 57 | { |
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| 58 | shorter++; |
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| 59 | pSetCoeff0(p,t); |
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| 60 | a = pNext(a) = p; |
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| 61 | pIter(p); |
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| 62 | } |
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| 63 | if (p==NULL) { pNext(a) = q; goto Finish;} |
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| 64 | if (q==NULL) { pNext(a) = p; goto Finish;} |
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| 65 | goto Top; |
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| 66 | |
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| 67 | Greater: |
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| 68 | a = pNext(a) = p; |
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| 69 | pIter(p); |
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| 70 | if (p==NULL) { pNext(a) = q; goto Finish;} |
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| 71 | goto Top; |
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| 72 | |
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| 73 | Smaller: |
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| 74 | a = pNext(a) = q; |
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| 75 | pIter(q); |
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| 76 | if (q==NULL) { pNext(a) = p; goto Finish;} |
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| 77 | goto Top; |
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| 78 | |
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| 79 | |
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| 80 | Finish: |
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| 81 | Shorter = shorter; |
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| 82 | |
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| 83 | pTest(pNext(&rp)); |
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| 84 | #ifdef PDEBUG |
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| 85 | assume(l - pLength(pNext(&rp)) == Shorter); |
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| 86 | #endif |
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| 87 | return pNext(&rp); |
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| 88 | } |
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| 89 | |
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