source: git/kernel/p_Add_q__T.cc @ 3a67ea7

spielwiese
Last change on this file since 3a67ea7 was 35aab3, checked in by Hans Schönemann <hannes@…>, 20 years ago
This commit was generated by cvs2svn to compensate for changes in r6879, which included commits to RCS files with non-trunk default branches. git-svn-id: file:///usr/local/Singular/svn/trunk@6880 2c84dea3-7e68-4137-9b89-c4e89433aadc
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1/****************************************
2*  Computer Algebra System SINGULAR     *
3****************************************/
4/***************************************************************
5 *  File:    p_Add_q__Template.cc
6 *  Purpose: template for p_Add_q
7 *  Author:  obachman (Olaf Bachmann)
8 *  Created: 8/00
9 *  Version: $Id: p_Add_q__T.cc,v 1.1.1.1 2003-10-06 12:15:58 Singular Exp $
10 *******************************************************************/
11
12/***************************************************************
13 *
14 * Returns:  p + q,
15 *           Shorter, where Shorter == Length(p) + Length(q) - Length(p+q);
16 * Destroys: p, q
17 *
18 ***************************************************************/
19LINKAGE poly p_Add_q(poly p, poly q, int &Shorter, const ring r)
20{
21  p_Test(p, r);
22  p_Test(q, r);
23#if PDEBUG > 0
24  int l = pLength(p) + pLength(q);
25#endif
26
27  // test for trivial cases
28  Shorter = 0;
29  if (q == NULL) return p;
30  if (p == NULL) return q;
31
32  number t, n1, n2;
33  int shorter = 0;
34  spolyrec rp;
35  poly a = &rp;
36  DECLARE_LENGTH(const unsigned long length = r->CmpL_Size);
37  DECLARE_ORDSGN(const long* ordsgn = r->ordsgn);
38
39  Top:     // compare p and q w.r.t. monomial ordering
40  p_MemCmp(p->exp, q->exp, length, ordsgn, goto Equal, goto Greater , goto Smaller);
41
42  Equal:
43  n1 = pGetCoeff(p);
44  n2 = pGetCoeff(q);
45  t = n_Add(n1,n2, r);
46  n_Delete(&n1, r);
47  n_Delete(&n2, r);
48  q = p_LmFreeAndNext(q, r);
49
50  if (n_IsZero(t, r))
51  {
52    shorter += 2;
53    n_Delete(&t, r);
54    p = p_LmFreeAndNext(p, r);
55  }
56  else
57  {
58    shorter++;
59    pSetCoeff0(p,t);
60    a = pNext(a) = p;
61    pIter(p);
62  }
63  if (p==NULL) { pNext(a) = q; goto Finish;}
64  if (q==NULL) { pNext(a) = p; goto Finish;}
65  goto Top;
66
67  Greater:
68  a = pNext(a) = p;
69  pIter(p);
70  if (p==NULL) { pNext(a) = q; goto Finish;}
71  goto Top;
72
73  Smaller:
74  a = pNext(a) = q;
75  pIter(q);
76  if (q==NULL) { pNext(a) = p; goto Finish;}
77  goto Top;
78
79
80  Finish:
81  Shorter = shorter;
82
83  p_Test(pNext(&rp), r);
84#if PDEBUG > 0
85  pAssume1(l - pLength(pNext(&rp)) == Shorter);
86#endif
87  return pNext(&rp);
88}
89
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