[35aab3] | 1 | /**************************************** |
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| 2 | * Computer Algebra System SINGULAR * |
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| 3 | ****************************************/ |
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[341696] | 4 | /* $Id$ */ |
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[35aab3] | 5 | |
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| 6 | /*************************************************************** |
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| 7 | * |
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| 8 | * File: polys-impl.cc |
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| 9 | * Purpose: low-level procuders for polys. |
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| 10 | * |
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| 11 | * If you touch anything here, you better know what you are doing. |
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| 12 | * What is here should not be used directly from other routines -- the |
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| 13 | * encapsulations in polys.[h,cc] should be used, instead. |
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| 14 | * |
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| 15 | ***************************************************************/ |
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| 16 | #ifndef POLYS_IMPL_CC |
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| 17 | #define POLYS_IMPL_CC |
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| 18 | |
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| 19 | #include <stdio.h> |
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| 20 | #include <string.h> |
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[0ceb74] | 21 | |
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| 22 | #include "config.h" |
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[35aab3] | 23 | |
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[b1dfaf] | 24 | #include <omalloc/omalloc.h> |
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[0ceb74] | 25 | #include <misc/auxiliary.h> |
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| 26 | |
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[35aab3] | 27 | #ifdef PDEBUG |
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| 28 | #undef NO_INLINE3 |
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| 29 | #define NO_INLINE3 |
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| 30 | #endif |
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[20b794] | 31 | #include <polys/monomials/polys-impl.h> |
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| 32 | |
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| 33 | #include <polys/monomials/ring.h> |
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| 34 | #include <reporter/reporter.h> |
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| 35 | #include <coeffs/numbers.h> |
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| 36 | #include <polys/monomials/ring.h> |
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[8a8c9e] | 37 | #include <polys/monomials/p_polys.h> |
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[20b794] | 38 | #include <polys/templates/p_Procs.h> |
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[6bec87] | 39 | #include <reporter/reporter.h> |
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[35aab3] | 40 | |
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| 41 | #ifdef PDEBUG |
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| 42 | int pDBsyzComp=0; |
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| 43 | #endif |
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| 44 | |
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| 45 | /*************************************************************** |
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| 46 | * |
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| 47 | * Storage Managament Routines |
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| 48 | * |
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| 49 | ***************************************************************/ |
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| 50 | |
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| 51 | |
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[0b5e3d] | 52 | static inline unsigned long GetBitFields(long e, |
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[35aab3] | 53 | unsigned int s, unsigned int n) |
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| 54 | { |
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[6f1441] | 55 | #define Sy_bit_L(x) (((unsigned long)1L)<<(x)) |
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| 56 | unsigned int i = 0; |
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| 57 | unsigned long ev = 0L; |
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[35aab3] | 58 | assume(n > 0 && s < BIT_SIZEOF_LONG); |
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| 59 | do |
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| 60 | { |
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| 61 | assume(s+i < BIT_SIZEOF_LONG); |
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[0b5e3d] | 62 | if (e > (long) i) ev |= Sy_bit_L(s+i); |
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[35aab3] | 63 | else break; |
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| 64 | i++; |
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| 65 | } |
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| 66 | while (i < n); |
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| 67 | return ev; |
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| 68 | } |
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| 69 | |
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| 70 | // Short Exponent Vectors are used for fast divisibility tests |
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| 71 | // ShortExpVectors "squeeze" an exponent vector into one word as follows: |
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| 72 | // Let n = BIT_SIZEOF_LONG / pVariables. |
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| 73 | // If n == 0 (i.e. pVariables > BIT_SIZE_OF_LONG), let m == the number |
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| 74 | // of non-zero exponents. If (m>BIT_SIZEOF_LONG), then sev = ~0, else |
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| 75 | // first m bits of sev are set to 1. |
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| 76 | // Otherwise (i.e. pVariables <= BIT_SIZE_OF_LONG) |
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| 77 | // represented by a bit-field of length n (resp. n+1 for some |
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| 78 | // exponents). If the value of an exponent is greater or equal to n, then |
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| 79 | // all of its respective n bits are set to 1. If the value of an exponent |
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| 80 | // is smaller than n, say m, then only the first m bits of the respective |
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| 81 | // n bits are set to 1, the others are set to 0. |
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| 82 | // This way, we have: |
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| 83 | // exp1 / exp2 ==> (ev1 & ~ev2) == 0, i.e., |
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| 84 | // if (ev1 & ~ev2) then exp1 does not divide exp2 |
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| 85 | unsigned long p_GetShortExpVector(poly p, ring r) |
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| 86 | { |
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| 87 | assume(p != NULL); |
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| 88 | if (p == NULL) return 0; |
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| 89 | unsigned long ev = 0; // short exponent vector |
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| 90 | unsigned int n = BIT_SIZEOF_LONG / r->N; // number of bits per exp |
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| 91 | unsigned int m1; // highest bit which is filled with (n+1) |
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| 92 | unsigned int i = 0, j=1; |
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| 93 | |
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| 94 | if (n == 0) |
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| 95 | { |
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| 96 | if (r->N <2*BIT_SIZEOF_LONG) |
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| 97 | { |
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| 98 | n=1; |
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| 99 | m1=0; |
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| 100 | } |
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| 101 | else |
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| 102 | { |
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| 103 | for (; j<=(unsigned long) r->N; j++) |
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| 104 | { |
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| 105 | if (p_GetExp(p,j,r) > 0) i++; |
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| 106 | if (i == BIT_SIZEOF_LONG) break; |
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| 107 | } |
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| 108 | if (i>0) |
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| 109 | ev = ~((unsigned long)0) >> ((unsigned long) (BIT_SIZEOF_LONG - i)); |
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| 110 | return ev; |
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| 111 | } |
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| 112 | } |
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| 113 | else |
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| 114 | { |
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| 115 | m1 = (n+1)*(BIT_SIZEOF_LONG - n*r->N); |
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| 116 | } |
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| 117 | |
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| 118 | n++; |
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| 119 | while (i<m1) |
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| 120 | { |
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| 121 | ev |= GetBitFields(p_GetExp(p, j,r), i, n); |
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| 122 | i += n; |
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| 123 | j++; |
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| 124 | } |
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| 125 | |
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| 126 | n--; |
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| 127 | while (i<BIT_SIZEOF_LONG) |
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| 128 | { |
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| 129 | ev |= GetBitFields(p_GetExp(p, j,r), i, n); |
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| 130 | i += n; |
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| 131 | j++; |
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| 132 | } |
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| 133 | return ev; |
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| 134 | } |
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| 135 | |
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| 136 | #endif // POLYS_IMPL_CC |
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