[493c477] | 1 | /* emacs edit mode for this file is -*- C++ -*- */ |
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[341696] | 2 | /* $Id$ */ |
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[9bab9f] | 3 | |
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[ab4548f] | 4 | #include <config.h> |
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| 5 | |
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[c5d0aed] | 6 | #define OM_NO_MALLOC_MACROS |
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| 7 | |
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| 8 | |
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[9bab9f] | 9 | #include "assert.h" |
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[93b061] | 10 | #include "debug.h" |
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| 11 | |
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[9bab9f] | 12 | #include "cf_defs.h" |
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| 13 | #include "canonicalform.h" |
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| 14 | #include "cf_iter.h" |
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| 15 | #include "cf_reval.h" |
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[edb4893] | 16 | #include "cf_primes.h" |
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[fbefc9] | 17 | #include "cf_algorithm.h" |
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[f63dbca] | 18 | #include "fac_util.h" |
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[71da5e] | 19 | #include "ftmpl_functions.h" |
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[49f1f45] | 20 | #include "ffreval.h" |
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[bb82f0] | 21 | #include "algext.h" |
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[598ff8b] | 22 | #include "fieldGCD.h" |
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[10af64] | 23 | #include "cf_gcd_smallp.h" |
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[edb4893] | 24 | |
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[c5d0aed] | 25 | |
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[f11d7b] | 26 | #ifdef HAVE_NTL |
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[034eec] | 27 | #include <NTL/ZZX.h> |
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[f11d7b] | 28 | #include "NTLconvert.h" |
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[a7ec94] | 29 | bool isPurePoly(const CanonicalForm & ); |
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| 30 | static CanonicalForm gcd_univar_ntl0( const CanonicalForm &, const CanonicalForm & ); |
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[c4f4fd] | 31 | static CanonicalForm gcd_univar_ntlp( const CanonicalForm &, const CanonicalForm & ); |
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[f11d7b] | 32 | #endif |
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| 33 | |
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[a7ec94] | 34 | static CanonicalForm cf_content ( const CanonicalForm &, const CanonicalForm & ); |
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| 35 | static bool gcd_avoid_mtaildegree ( CanonicalForm &, CanonicalForm &, CanonicalForm & ); |
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| 36 | static void cf_prepgcd( const CanonicalForm &, const CanonicalForm &, int &, int &, int & ); |
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[edb4893] | 37 | |
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[27bb97f] | 38 | void out_cf(const char *s1,const CanonicalForm &f,const char *s2); |
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[6f62c3] | 39 | |
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[110718] | 40 | CanonicalForm chinrem_gcd(const CanonicalForm & FF,const CanonicalForm & GG); |
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| 41 | CanonicalForm newGCD(CanonicalForm A, CanonicalForm B); |
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[f4b180] | 42 | |
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[f63dbca] | 43 | bool |
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| 44 | gcd_test_one ( const CanonicalForm & f, const CanonicalForm & g, bool swap ) |
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[9bab9f] | 45 | { |
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| 46 | int count = 0; |
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| 47 | // assume polys have same level; |
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| 48 | CFRandom * sample = CFRandomFactory::generate(); |
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[f63dbca] | 49 | REvaluation e( 2, tmax( f.level(), g.level() ), *sample ); |
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[9bab9f] | 50 | delete sample; |
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[f63dbca] | 51 | CanonicalForm lcf, lcg; |
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[6f62c3] | 52 | if ( swap ) |
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| 53 | { |
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[150dc8] | 54 | lcf = swapvar( LC( f ), Variable(1), f.mvar() ); |
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| 55 | lcg = swapvar( LC( g ), Variable(1), f.mvar() ); |
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[f63dbca] | 56 | } |
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[6f62c3] | 57 | else |
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| 58 | { |
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[150dc8] | 59 | lcf = LC( f, Variable(1) ); |
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| 60 | lcg = LC( g, Variable(1) ); |
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[f63dbca] | 61 | } |
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[df497a] | 62 | #define TEST_ONE_MAX 50 |
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| 63 | while ( ( e( lcf ).isZero() || e( lcg ).isZero() ) && count < TEST_ONE_MAX ) |
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| 64 | { |
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[150dc8] | 65 | e.nextpoint(); |
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| 66 | count++; |
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[9bab9f] | 67 | } |
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[df497a] | 68 | if ( count == TEST_ONE_MAX ) |
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[150dc8] | 69 | return false; |
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[f63dbca] | 70 | CanonicalForm F, G; |
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[6f62c3] | 71 | if ( swap ) |
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| 72 | { |
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[150dc8] | 73 | F=swapvar( f, Variable(1), f.mvar() ); |
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| 74 | G=swapvar( g, Variable(1), g.mvar() ); |
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[f63dbca] | 75 | } |
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[6f62c3] | 76 | else |
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| 77 | { |
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[150dc8] | 78 | F = f; |
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| 79 | G = g; |
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[f63dbca] | 80 | } |
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[9bab9f] | 81 | if ( e(F).taildegree() > 0 && e(G).taildegree() > 0 ) |
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[150dc8] | 82 | return false; |
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[9bab9f] | 83 | return gcd( e( F ), e( G ) ).degree() < 1; |
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| 84 | } |
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| 85 | |
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[dd3e561] | 86 | //{{{ static CanonicalForm icontent ( const CanonicalForm & f, const CanonicalForm & c ) |
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| 87 | //{{{ docu |
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| 88 | // |
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| 89 | // icontent() - return gcd of c and all coefficients of f which |
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| 90 | // are in a coefficient domain. |
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| 91 | // |
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| 92 | // Used by icontent(). |
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| 93 | // |
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| 94 | //}}} |
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[9bab9f] | 95 | static CanonicalForm |
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| 96 | icontent ( const CanonicalForm & f, const CanonicalForm & c ) |
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| 97 | { |
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[c30347] | 98 | if ( f.inBaseDomain() ) |
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| 99 | { |
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| 100 | if (c.isZero()) return abs(f); |
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| 101 | return bgcd( f, c ); |
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| 102 | } |
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[ef20c7] | 103 | //else if ( f.inCoeffDomain() ) |
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| 104 | // return gcd(f,c); |
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[c30347] | 105 | else |
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| 106 | { |
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[150dc8] | 107 | CanonicalForm g = c; |
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| 108 | for ( CFIterator i = f; i.hasTerms() && ! g.isOne(); i++ ) |
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| 109 | g = icontent( i.coeff(), g ); |
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| 110 | return g; |
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[9bab9f] | 111 | } |
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| 112 | } |
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[dd3e561] | 113 | //}}} |
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[9bab9f] | 114 | |
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[dd3e561] | 115 | //{{{ CanonicalForm icontent ( const CanonicalForm & f ) |
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| 116 | //{{{ docu |
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| 117 | // |
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| 118 | // icontent() - return gcd over all coefficients of f which are |
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| 119 | // in a coefficient domain. |
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| 120 | // |
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| 121 | //}}} |
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[9bab9f] | 122 | CanonicalForm |
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| 123 | icontent ( const CanonicalForm & f ) |
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| 124 | { |
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| 125 | return icontent( f, 0 ); |
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| 126 | } |
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[dd3e561] | 127 | //}}} |
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[9bab9f] | 128 | |
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[dd3e561] | 129 | //{{{ CanonicalForm extgcd ( const CanonicalForm & f, const CanonicalForm & g, CanonicalForm & a, CanonicalForm & b ) |
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| 130 | //{{{ docu |
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| 131 | // |
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| 132 | // extgcd() - returns polynomial extended gcd of f and g. |
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| 133 | // |
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| 134 | // Returns gcd(f, g) and a and b sucht that f*a+g*b=gcd(f, g). |
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| 135 | // The gcd is calculated using an extended euclidean polynomial |
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| 136 | // remainder sequence, so f and g should be polynomials over an |
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| 137 | // euclidean domain. Normalizes result. |
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| 138 | // |
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| 139 | // Note: be sure that f and g have the same level! |
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| 140 | // |
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| 141 | //}}} |
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[9bab9f] | 142 | CanonicalForm |
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| 143 | extgcd ( const CanonicalForm & f, const CanonicalForm & g, CanonicalForm & a, CanonicalForm & b ) |
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| 144 | { |
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[034eec] | 145 | #ifdef HAVE_NTL |
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[963057] | 146 | if (isOn(SW_USE_NTL_GCD_P) && ( getCharacteristic() > 0 ) && (CFFactory::gettype() != GaloisFieldDomain) |
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[a86cda] | 147 | && (f.level()==g.level()) && isPurePoly(f) && isPurePoly(g)) |
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[034eec] | 148 | { |
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[c6eecb] | 149 | if (fac_NTL_char!=getCharacteristic()) |
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| 150 | { |
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| 151 | fac_NTL_char=getCharacteristic(); |
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| 152 | #ifdef NTL_ZZ |
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| 153 | ZZ r; |
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| 154 | r=getCharacteristic(); |
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| 155 | ZZ_pContext ccc(r); |
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| 156 | #else |
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| 157 | zz_pContext ccc(getCharacteristic()); |
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| 158 | #endif |
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| 159 | ccc.restore(); |
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| 160 | #ifdef NTL_ZZ |
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| 161 | ZZ_p::init(r); |
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| 162 | #else |
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| 163 | zz_p::init(getCharacteristic()); |
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| 164 | #endif |
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| 165 | } |
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| 166 | #ifdef NTL_ZZ |
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| 167 | ZZ_pX F1=convertFacCF2NTLZZpX(f); |
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| 168 | ZZ_pX G1=convertFacCF2NTLZZpX(g); |
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| 169 | ZZ_pX R; |
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| 170 | ZZ_pX A,B; |
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| 171 | XGCD(R,A,B,F1,G1); |
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| 172 | a=convertNTLZZpX2CF(A,f.mvar()); |
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| 173 | b=convertNTLZZpX2CF(B,f.mvar()); |
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| 174 | return convertNTLZZpX2CF(R,f.mvar()); |
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| 175 | #else |
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[034eec] | 176 | zz_pX F1=convertFacCF2NTLzzpX(f); |
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| 177 | zz_pX G1=convertFacCF2NTLzzpX(g); |
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| 178 | zz_pX R; |
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| 179 | zz_pX A,B; |
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| 180 | XGCD(R,A,B,F1,G1); |
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| 181 | a=convertNTLzzpX2CF(A,f.mvar()); |
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| 182 | b=convertNTLzzpX2CF(B,f.mvar()); |
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| 183 | return convertNTLzzpX2CF(R,f.mvar()); |
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[c6eecb] | 184 | #endif |
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[034eec] | 185 | } |
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[a86cda] | 186 | if (isOn(SW_USE_NTL_GCD_0) && ( getCharacteristic() ==0) |
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| 187 | && (f.level()==g.level()) && isPurePoly(f) && isPurePoly(g)) |
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| 188 | { |
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| 189 | CanonicalForm fc=bCommonDen(f); |
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| 190 | CanonicalForm gc=bCommonDen(g); |
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| 191 | ZZX F1=convertFacCF2NTLZZX(f*fc); |
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| 192 | ZZX G1=convertFacCF2NTLZZX(g*gc); |
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| 193 | ZZX R=GCD(F1,G1); |
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| 194 | CanonicalForm r=convertNTLZZX2CF(R,f.mvar()); |
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| 195 | ZZ RR; |
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| 196 | ZZX A,B; |
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| 197 | if (r.inCoeffDomain()) |
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| 198 | { |
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| 199 | XGCD(RR,A,B,F1,G1,1); |
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| 200 | CanonicalForm rr=convertZZ2CF(RR); |
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| 201 | ASSERT (!rr.isZero(), "NTL:XGCD failed"); |
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| 202 | a=convertNTLZZX2CF(A,f.mvar())*fc/rr; |
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| 203 | b=convertNTLZZX2CF(B,f.mvar())*gc/rr; |
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| 204 | return CanonicalForm(1); |
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| 205 | } |
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| 206 | else |
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| 207 | { |
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| 208 | fc=bCommonDen(f); |
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| 209 | gc=bCommonDen(g); |
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| 210 | F1=convertFacCF2NTLZZX(f*fc/r); |
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| 211 | G1=convertFacCF2NTLZZX(g*gc/r); |
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| 212 | XGCD(RR,A,B,F1,G1,1); |
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| 213 | a=convertNTLZZX2CF(A,f.mvar())*fc; |
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| 214 | b=convertNTLZZX2CF(B,f.mvar())*gc; |
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| 215 | CanonicalForm rr=convertZZ2CF(RR); |
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| 216 | ASSERT (!rr.isZero(), "NTL:XGCD failed"); |
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| 217 | r*=rr; |
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| 218 | if ( r.sign() < 0 ) { r= -r; a= -a; b= -b; } |
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| 219 | return r; |
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| 220 | } |
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| 221 | } |
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[034eec] | 222 | #endif |
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[a86cda] | 223 | // may contain bug in the co-factors, see track 107 |
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[034eec] | 224 | CanonicalForm contf = content( f ); |
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| 225 | CanonicalForm contg = content( g ); |
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[9bab9f] | 226 | |
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[034eec] | 227 | CanonicalForm p0 = f / contf, p1 = g / contg; |
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| 228 | CanonicalForm f0 = 1, f1 = 0, g0 = 0, g1 = 1, q, r; |
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[9bab9f] | 229 | |
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[c6eecb] | 230 | while ( ! p1.isZero() ) |
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| 231 | { |
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[034eec] | 232 | divrem( p0, p1, q, r ); |
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| 233 | p0 = p1; p1 = r; |
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| 234 | r = g0 - g1 * q; |
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| 235 | g0 = g1; g1 = r; |
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| 236 | r = f0 - f1 * q; |
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| 237 | f0 = f1; f1 = r; |
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| 238 | } |
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| 239 | CanonicalForm contp0 = content( p0 ); |
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| 240 | a = f0 / ( contf * contp0 ); |
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| 241 | b = g0 / ( contg * contp0 ); |
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| 242 | p0 /= contp0; |
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[c6eecb] | 243 | if ( p0.sign() < 0 ) |
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| 244 | { |
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[034eec] | 245 | p0 = -p0; |
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| 246 | a = -a; |
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| 247 | b = -b; |
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| 248 | } |
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| 249 | return p0; |
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[9bab9f] | 250 | } |
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[dd3e561] | 251 | //}}} |
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[9bab9f] | 252 | |
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[a7ec94] | 253 | //{{{ static CanonicalForm balance ( const CanonicalForm & f, const CanonicalForm & q ) |
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| 254 | //{{{ docu |
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| 255 | // |
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| 256 | // balance() - map f from positive to symmetric representation |
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| 257 | // mod q. |
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| 258 | // |
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| 259 | // This makes sense for univariate polynomials over Z only. |
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| 260 | // q should be an integer. |
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| 261 | // |
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| 262 | // Used by gcd_poly_univar0(). |
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| 263 | // |
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| 264 | //}}} |
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[edb4893] | 265 | static CanonicalForm |
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[a7ec94] | 266 | balance ( const CanonicalForm & f, const CanonicalForm & q ) |
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[edb4893] | 267 | { |
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[a7ec94] | 268 | Variable x = f.mvar(); |
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| 269 | CanonicalForm result = 0, qh = q / 2; |
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| 270 | CanonicalForm c; |
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| 271 | CFIterator i; |
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| 272 | for ( i = f; i.hasTerms(); i++ ) { |
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| 273 | c = mod( i.coeff(), q ); |
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| 274 | if ( c > qh ) |
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| 275 | result += power( x, i.exp() ) * (c - q); |
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| 276 | else |
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| 277 | result += power( x, i.exp() ) * c; |
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[edb4893] | 278 | } |
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[a7ec94] | 279 | return result; |
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| 280 | } |
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| 281 | //}}} |
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| 282 | |
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[01e8874] | 283 | static CanonicalForm gcd_poly_univar0( const CanonicalForm & F, const CanonicalForm & G, bool primitive ) |
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[a7ec94] | 284 | { |
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[f11d7b] | 285 | CanonicalForm f, g, c, cg, cl, BB, B, M, q, Dp, newD, D, newq; |
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[01e8874] | 286 | int p, i; |
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[f11d7b] | 287 | |
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| 288 | if ( primitive ) |
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| 289 | { |
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| 290 | f = F; |
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| 291 | g = G; |
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| 292 | c = 1; |
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| 293 | } |
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| 294 | else |
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| 295 | { |
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| 296 | CanonicalForm cF = content( F ), cG = content( G ); |
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| 297 | f = F / cF; |
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| 298 | g = G / cG; |
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| 299 | c = bgcd( cF, cG ); |
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| 300 | } |
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| 301 | cg = gcd( f.lc(), g.lc() ); |
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| 302 | cl = ( f.lc() / cg ) * g.lc(); |
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[93b061] | 303 | // B = 2 * cg * tmin( |
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[150dc8] | 304 | // maxnorm(f)*power(CanonicalForm(2),f.degree())*isqrt(f.degree()+1), |
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| 305 | // maxnorm(g)*power(CanonicalForm(2),g.degree())*isqrt(g.degree()+1) |
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| 306 | // )+1; |
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[f11d7b] | 307 | M = tmin( maxNorm(f), maxNorm(g) ); |
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| 308 | BB = power(CanonicalForm(2),tmin(f.degree(),g.degree()))*M; |
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| 309 | q = 0; |
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| 310 | i = cf_getNumSmallPrimes() - 1; |
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| 311 | while ( true ) |
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| 312 | { |
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| 313 | B = BB; |
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| 314 | while ( i >= 0 && q < B ) |
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| 315 | { |
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| 316 | p = cf_getSmallPrime( i ); |
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| 317 | i--; |
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| 318 | while ( i >= 0 && mod( cl, p ) == 0 ) |
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| 319 | { |
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| 320 | p = cf_getSmallPrime( i ); |
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| 321 | i--; |
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| 322 | } |
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| 323 | setCharacteristic( p ); |
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| 324 | Dp = gcd( mapinto( f ), mapinto( g ) ); |
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| 325 | Dp = ( Dp / Dp.lc() ) * mapinto( cg ); |
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| 326 | setCharacteristic( 0 ); |
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| 327 | if ( Dp.degree() == 0 ) |
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| 328 | return c; |
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| 329 | if ( q.isZero() ) |
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| 330 | { |
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| 331 | D = mapinto( Dp ); |
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| 332 | q = p; |
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| 333 | B = power(CanonicalForm(2),D.degree())*M+1; |
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| 334 | } |
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| 335 | else |
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| 336 | { |
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| 337 | if ( Dp.degree() == D.degree() ) |
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| 338 | { |
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| 339 | chineseRemainder( D, q, mapinto( Dp ), p, newD, newq ); |
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| 340 | q = newq; |
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| 341 | D = newD; |
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[150dc8] | 342 | } |
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[f11d7b] | 343 | else if ( Dp.degree() < D.degree() ) |
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| 344 | { |
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| 345 | // all previous p's are bad primes |
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| 346 | q = p; |
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| 347 | D = mapinto( Dp ); |
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| 348 | B = power(CanonicalForm(2),D.degree())*M+1; |
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[150dc8] | 349 | } |
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[f11d7b] | 350 | // else p is a bad prime |
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| 351 | } |
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| 352 | } |
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| 353 | if ( i >= 0 ) |
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| 354 | { |
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| 355 | // now balance D mod q |
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| 356 | D = pp( balance( D, q ) ); |
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[ebc602] | 357 | if ( fdivides( D, f ) && fdivides( D, g ) ) |
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[f11d7b] | 358 | return D * c; |
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| 359 | else |
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| 360 | q = 0; |
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[edb4893] | 361 | } |
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[f11d7b] | 362 | else |
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[a7ec94] | 363 | return gcd_poly( F, G ); |
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[f11d7b] | 364 | DEBOUTLN( cerr, "another try ..." ); |
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| 365 | } |
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[edb4893] | 366 | } |
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| 367 | |
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[c4f4fd] | 368 | static CanonicalForm |
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| 369 | gcd_poly_p( const CanonicalForm & f, const CanonicalForm & g ) |
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| 370 | { |
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| 371 | CanonicalForm pi, pi1; |
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| 372 | CanonicalForm C, Ci, Ci1, Hi, bi, pi2; |
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| 373 | bool bpure; |
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| 374 | int delta = degree( f ) - degree( g ); |
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| 375 | |
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| 376 | if ( delta >= 0 ) |
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| 377 | { |
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| 378 | pi = f; pi1 = g; |
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| 379 | } |
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| 380 | else |
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| 381 | { |
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| 382 | pi = g; pi1 = f; delta = -delta; |
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| 383 | } |
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| 384 | Ci = content( pi ); Ci1 = content( pi1 ); |
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| 385 | pi1 = pi1 / Ci1; pi = pi / Ci; |
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| 386 | C = gcd( Ci, Ci1 ); |
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| 387 | if ( !( pi.isUnivariate() && pi1.isUnivariate() ) ) |
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| 388 | { |
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| 389 | //out_cf("F:",f,"\n"); |
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| 390 | //out_cf("G:",g,"\n"); |
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| 391 | //out_cf("newGCD:",newGCD(f,g),"\n"); |
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| 392 | if (isOn(SW_USE_GCD_P) && (getCharacteristic()>0)) |
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| 393 | { |
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| 394 | return newGCD(f,g); |
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| 395 | } |
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| 396 | if ( gcd_test_one( pi1, pi, true ) ) |
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| 397 | { |
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| 398 | C=abs(C); |
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| 399 | //out_cf("GCD:",C,"\n"); |
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| 400 | return C; |
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| 401 | } |
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| 402 | bpure = false; |
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| 403 | } |
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| 404 | else |
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| 405 | { |
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| 406 | bpure = isPurePoly(pi) && isPurePoly(pi1); |
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| 407 | #ifdef HAVE_NTL |
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| 408 | if ( isOn(SW_USE_NTL_GCD_P) && bpure && (CFFactory::gettype() != GaloisFieldDomain)) |
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| 409 | return gcd_univar_ntlp(pi, pi1 ) * C; |
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| 410 | #endif |
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| 411 | } |
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| 412 | Variable v = f.mvar(); |
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| 413 | Hi = power( LC( pi1, v ), delta ); |
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| 414 | if ( (delta+1) % 2 ) |
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| 415 | bi = 1; |
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| 416 | else |
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| 417 | bi = -1; |
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| 418 | while ( degree( pi1, v ) > 0 ) |
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| 419 | { |
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| 420 | pi2 = psr( pi, pi1, v ); |
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| 421 | pi2 = pi2 / bi; |
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| 422 | pi = pi1; pi1 = pi2; |
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| 423 | if ( degree( pi1, v ) > 0 ) |
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| 424 | { |
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| 425 | delta = degree( pi, v ) - degree( pi1, v ); |
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| 426 | if ( (delta+1) % 2 ) |
---|
| 427 | bi = LC( pi, v ) * power( Hi, delta ); |
---|
| 428 | else |
---|
| 429 | bi = -LC( pi, v ) * power( Hi, delta ); |
---|
| 430 | Hi = power( LC( pi1, v ), delta ) / power( Hi, delta-1 ); |
---|
| 431 | } |
---|
| 432 | } |
---|
| 433 | if ( degree( pi1, v ) == 0 ) |
---|
| 434 | { |
---|
| 435 | C=abs(C); |
---|
| 436 | //out_cf("GCD:",C,"\n"); |
---|
| 437 | return C; |
---|
| 438 | } |
---|
| 439 | pi /= content( pi ); |
---|
| 440 | if ( bpure ) |
---|
| 441 | pi /= pi.lc(); |
---|
| 442 | C=abs(C*pi); |
---|
| 443 | //out_cf("GCD:",C,"\n"); |
---|
| 444 | return C; |
---|
| 445 | } |
---|
| 446 | |
---|
[a7ec94] | 447 | static CanonicalForm |
---|
| 448 | gcd_poly_0( const CanonicalForm & f, const CanonicalForm & g ) |
---|
| 449 | { |
---|
| 450 | CanonicalForm pi, pi1; |
---|
[df497a] | 451 | CanonicalForm C, Ci, Ci1, Hi, bi, pi2; |
---|
[a7ec94] | 452 | int delta = degree( f ) - degree( g ); |
---|
| 453 | |
---|
| 454 | if ( delta >= 0 ) |
---|
| 455 | { |
---|
| 456 | pi = f; pi1 = g; |
---|
| 457 | } |
---|
| 458 | else |
---|
| 459 | { |
---|
| 460 | pi = g; pi1 = f; delta = -delta; |
---|
| 461 | } |
---|
[9bab9f] | 462 | Ci = content( pi ); Ci1 = content( pi1 ); |
---|
| 463 | pi1 = pi1 / Ci1; pi = pi / Ci; |
---|
[df497a] | 464 | C = gcd( Ci, Ci1 ); |
---|
[034eec] | 465 | if ( pi.isUnivariate() && pi1.isUnivariate() ) |
---|
| 466 | { |
---|
| 467 | #ifdef HAVE_NTL |
---|
[a7ec94] | 468 | if ( isOn(SW_USE_NTL_GCD_0) && isPurePoly(pi) && isPurePoly(pi1) ) |
---|
| 469 | return gcd_univar_ntl0(pi, pi1 ) * C; |
---|
[df497a] | 470 | #endif |
---|
[a7ec94] | 471 | return gcd_poly_univar0( pi, pi1, true ) * C; |
---|
[edb4893] | 472 | } |
---|
[034eec] | 473 | else if ( gcd_test_one( pi1, pi, true ) ) |
---|
| 474 | return C; |
---|
[a7ec94] | 475 | Variable v = f.mvar(); |
---|
[9bab9f] | 476 | Hi = power( LC( pi1, v ), delta ); |
---|
| 477 | if ( (delta+1) % 2 ) |
---|
[150dc8] | 478 | bi = 1; |
---|
[9bab9f] | 479 | else |
---|
[150dc8] | 480 | bi = -1; |
---|
[6f62c3] | 481 | while ( degree( pi1, v ) > 0 ) |
---|
| 482 | { |
---|
[150dc8] | 483 | pi2 = psr( pi, pi1, v ); |
---|
| 484 | pi2 = pi2 / bi; |
---|
| 485 | pi = pi1; pi1 = pi2; |
---|
[6f62c3] | 486 | if ( degree( pi1, v ) > 0 ) |
---|
| 487 | { |
---|
[150dc8] | 488 | delta = degree( pi, v ) - degree( pi1, v ); |
---|
| 489 | if ( (delta+1) % 2 ) |
---|
| 490 | bi = LC( pi, v ) * power( Hi, delta ); |
---|
| 491 | else |
---|
| 492 | bi = -LC( pi, v ) * power( Hi, delta ); |
---|
| 493 | Hi = power( LC( pi1, v ), delta ) / power( Hi, delta-1 ); |
---|
| 494 | } |
---|
[9bab9f] | 495 | } |
---|
| 496 | if ( degree( pi1, v ) == 0 ) |
---|
[150dc8] | 497 | return C; |
---|
[df497a] | 498 | else |
---|
[150dc8] | 499 | return C * pp( pi ); |
---|
[9bab9f] | 500 | } |
---|
| 501 | |
---|
[b809a8] | 502 | //{{{ CanonicalForm gcd_poly ( const CanonicalForm & f, const CanonicalForm & g ) |
---|
[dd3e561] | 503 | //{{{ docu |
---|
| 504 | // |
---|
| 505 | // gcd_poly() - calculate polynomial gcd. |
---|
| 506 | // |
---|
| 507 | // This is the dispatcher for polynomial gcd calculation. We call either |
---|
| 508 | // ezgcd(), sparsemod() or gcd_poly1() in dependecy on the current |
---|
| 509 | // characteristic and settings of SW_USE_EZGCD and SW_USE_SPARSEMOD, resp. |
---|
| 510 | // |
---|
| 511 | // Used by gcd() and gcd_poly_univar0(). |
---|
| 512 | // |
---|
| 513 | //}}} |
---|
[0b6919] | 514 | #if 0 |
---|
[bfc606] | 515 | int si_factor_reminder=1; |
---|
[0b6919] | 516 | #endif |
---|
[b809a8] | 517 | CanonicalForm gcd_poly ( const CanonicalForm & f, const CanonicalForm & g ) |
---|
[f63dbca] | 518 | { |
---|
[110718] | 519 | CanonicalForm fc, gc, d1; |
---|
| 520 | int mp, cc, p1, pe; |
---|
| 521 | mp = f.level()+1; |
---|
[ed9927] | 522 | bool fc_isUnivariate=f.isUnivariate(); |
---|
| 523 | bool gc_isUnivariate=g.isUnivariate(); |
---|
| 524 | bool fc_and_gc_Univariate=fc_isUnivariate && gc_isUnivariate; |
---|
[1e6de6] | 525 | #if 1 |
---|
[c30347] | 526 | if (( getCharacteristic() == 0 ) |
---|
| 527 | && (f.level() >4) |
---|
| 528 | && (g.level() >4) |
---|
| 529 | && isOn( SW_USE_CHINREM_GCD) |
---|
[ed9927] | 530 | && (!fc_and_gc_Univariate) |
---|
[c30347] | 531 | && (isPurePoly_m(f)) |
---|
| 532 | && (isPurePoly_m(g)) |
---|
| 533 | ) |
---|
| 534 | { |
---|
| 535 | return chinrem_gcd( f, g ); |
---|
| 536 | } |
---|
| 537 | #endif |
---|
[ed9927] | 538 | cf_prepgcd( f, g, cc, p1, pe); |
---|
| 539 | if ( cc != 0 ) |
---|
[110718] | 540 | { |
---|
[ed9927] | 541 | if ( cc > 0 ) |
---|
[abfc3b] | 542 | { |
---|
[ed9927] | 543 | fc = replacevar( f, Variable(cc), Variable(mp) ); |
---|
| 544 | gc = g; |
---|
[e074407] | 545 | } |
---|
[ed9927] | 546 | else |
---|
[110718] | 547 | { |
---|
[ed9927] | 548 | fc = replacevar( g, Variable(-cc), Variable(mp) ); |
---|
| 549 | gc = f; |
---|
[110718] | 550 | } |
---|
[ed9927] | 551 | return cf_content( fc, gc ); |
---|
| 552 | } |
---|
| 553 | // now each appearing variable is in f and g |
---|
| 554 | fc = f; |
---|
| 555 | gc = g; |
---|
| 556 | if( gcd_avoid_mtaildegree ( fc, gc, d1 ) ) |
---|
| 557 | return d1; |
---|
| 558 | if ( getCharacteristic() != 0 ) |
---|
| 559 | { |
---|
[e6f7ee1] | 560 | if ((!fc_and_gc_Univariate) |
---|
| 561 | && isOn(SW_USE_fieldGCD) |
---|
[598ff8b] | 562 | && (getCharacteristic() >100)) |
---|
| 563 | { |
---|
[ad8e1b] | 564 | return fieldGCD(f,g); |
---|
[598ff8b] | 565 | } |
---|
| 566 | else if (isOn( SW_USE_EZGCD_P ) && (!fc_and_gc_Univariate)) |
---|
[49f1f45] | 567 | { |
---|
[c4f4fd] | 568 | if ( pe == 1 ) |
---|
| 569 | fc = fin_ezgcd( fc, gc ); |
---|
| 570 | else if ( pe > 0 )// no variable at position 1 |
---|
| 571 | { |
---|
| 572 | fc = replacevar( fc, Variable(pe), Variable(1) ); |
---|
| 573 | gc = replacevar( gc, Variable(pe), Variable(1) ); |
---|
| 574 | fc = replacevar( fin_ezgcd( fc, gc ), Variable(1), Variable(pe) ); |
---|
| 575 | } |
---|
| 576 | else |
---|
| 577 | { |
---|
| 578 | pe = -pe; |
---|
| 579 | fc = swapvar( fc, Variable(pe), Variable(1) ); |
---|
| 580 | gc = swapvar( gc, Variable(pe), Variable(1) ); |
---|
| 581 | fc = swapvar( fin_ezgcd( fc, gc ), Variable(1), Variable(pe) ); |
---|
| 582 | } |
---|
[c30347] | 583 | } |
---|
[ed9927] | 584 | else if (isOn(SW_USE_GCD_P)) |
---|
| 585 | { |
---|
| 586 | fc=newGCD(fc,gc); |
---|
| 587 | } |
---|
[10af64] | 588 | else if (isOn(SW_USE_FF_MOD_GCD) && !fc_and_gc_Univariate) |
---|
| 589 | { |
---|
| 590 | Variable a; |
---|
| 591 | if (hasFirstAlgVar (fc, a) || hasFirstAlgVar (gc, a)) |
---|
| 592 | { |
---|
| 593 | fc=GCD_Fp_extension (fc, gc, a); |
---|
| 594 | } |
---|
| 595 | if (CFFactory::gettype() == GaloisFieldDomain) |
---|
| 596 | { |
---|
| 597 | fc=GCD_GF (fc, gc); |
---|
| 598 | } |
---|
| 599 | fc=GCD_small_p (fc, gc); |
---|
| 600 | } |
---|
[ed9927] | 601 | else if ( p1 == fc.level() ) |
---|
| 602 | fc = gcd_poly_p( fc, gc ); |
---|
| 603 | else |
---|
| 604 | { |
---|
| 605 | fc = replacevar( fc, Variable(p1), Variable(mp) ); |
---|
| 606 | gc = replacevar( gc, Variable(p1), Variable(mp) ); |
---|
| 607 | fc = replacevar( gcd_poly_p( fc, gc ), Variable(mp), Variable(p1) ); |
---|
| 608 | } |
---|
[110718] | 609 | } |
---|
[c30347] | 610 | else if (!fc_and_gc_Univariate) |
---|
[110718] | 611 | { |
---|
[c30347] | 612 | if ( |
---|
| 613 | isOn(SW_USE_CHINREM_GCD) |
---|
[ed9927] | 614 | && (gc.level() >5) |
---|
| 615 | && (fc.level() >5) |
---|
| 616 | && (isPurePoly_m(fc)) && (isPurePoly_m(gc)) |
---|
[c30347] | 617 | ) |
---|
| 618 | { |
---|
[ed9927] | 619 | #if 0 |
---|
| 620 | if ( p1 == fc.level() ) |
---|
| 621 | fc = chinrem_gcd( fc, gc ); |
---|
| 622 | else |
---|
| 623 | { |
---|
| 624 | fc = replacevar( fc, Variable(p1), Variable(mp) ); |
---|
| 625 | gc = replacevar( gc, Variable(p1), Variable(mp) ); |
---|
| 626 | fc = replacevar( chinrem_gcd( fc, gc ), Variable(mp), Variable(p1) ); |
---|
| 627 | } |
---|
| 628 | #else |
---|
| 629 | fc = chinrem_gcd( fc, gc); |
---|
| 630 | #endif |
---|
[c30347] | 631 | } |
---|
[e6f7ee1] | 632 | else if ( isOn( SW_USE_EZGCD ) ) |
---|
[110718] | 633 | { |
---|
[ed9927] | 634 | if ( pe == 1 ) |
---|
| 635 | fc = ezgcd( fc, gc ); |
---|
| 636 | else if ( pe > 0 )// no variable at position 1 |
---|
| 637 | { |
---|
| 638 | fc = replacevar( fc, Variable(pe), Variable(1) ); |
---|
| 639 | gc = replacevar( gc, Variable(pe), Variable(1) ); |
---|
| 640 | fc = replacevar( ezgcd( fc, gc ), Variable(1), Variable(pe) ); |
---|
| 641 | } |
---|
| 642 | else |
---|
| 643 | { |
---|
| 644 | pe = -pe; |
---|
| 645 | fc = swapvar( fc, Variable(pe), Variable(1) ); |
---|
| 646 | gc = swapvar( gc, Variable(pe), Variable(1) ); |
---|
| 647 | fc = swapvar( ezgcd( fc, gc ), Variable(1), Variable(pe) ); |
---|
| 648 | } |
---|
[1b73cc0] | 649 | } |
---|
[110718] | 650 | else if ( |
---|
| 651 | isOn(SW_USE_CHINREM_GCD) |
---|
[ed9927] | 652 | && (isPurePoly_m(fc)) && (isPurePoly_m(gc)) |
---|
[110718] | 653 | ) |
---|
[de1a82] | 654 | { |
---|
[ed9927] | 655 | #if 0 |
---|
| 656 | if ( p1 == fc.level() ) |
---|
| 657 | fc = chinrem_gcd( fc, gc ); |
---|
| 658 | else |
---|
| 659 | { |
---|
| 660 | fc = replacevar( fc, Variable(p1), Variable(mp) ); |
---|
| 661 | gc = replacevar( gc, Variable(p1), Variable(mp) ); |
---|
| 662 | fc = replacevar( chinrem_gcd( fc, gc ), Variable(mp), Variable(p1) ); |
---|
| 663 | } |
---|
| 664 | #else |
---|
| 665 | fc = chinrem_gcd( fc, gc); |
---|
| 666 | #endif |
---|
[f63dbca] | 667 | } |
---|
[c30347] | 668 | else |
---|
| 669 | { |
---|
[ed9927] | 670 | fc = gcd_poly_0( fc, gc ); |
---|
[c30347] | 671 | } |
---|
[110718] | 672 | } |
---|
| 673 | else |
---|
| 674 | { |
---|
| 675 | fc = gcd_poly_0( fc, gc ); |
---|
| 676 | } |
---|
| 677 | if ( d1.degree() > 0 ) |
---|
| 678 | fc *= d1; |
---|
| 679 | return fc; |
---|
[f63dbca] | 680 | } |
---|
[dd3e561] | 681 | //}}} |
---|
[93b061] | 682 | |
---|
[dd3e561] | 683 | //{{{ static CanonicalForm cf_content ( const CanonicalForm & f, const CanonicalForm & g ) |
---|
| 684 | //{{{ docu |
---|
| 685 | // |
---|
| 686 | // cf_content() - return gcd(g, content(f)). |
---|
| 687 | // |
---|
| 688 | // content(f) is calculated with respect to f's main variable. |
---|
| 689 | // |
---|
| 690 | // Used by gcd(), content(), content( CF, Variable ). |
---|
| 691 | // |
---|
| 692 | //}}} |
---|
[9bab9f] | 693 | static CanonicalForm |
---|
| 694 | cf_content ( const CanonicalForm & f, const CanonicalForm & g ) |
---|
| 695 | { |
---|
[6f62c3] | 696 | if ( f.inPolyDomain() || ( f.inExtension() && ! getReduce( f.mvar() ) ) ) |
---|
| 697 | { |
---|
[150dc8] | 698 | CFIterator i = f; |
---|
| 699 | CanonicalForm result = g; |
---|
[6f62c3] | 700 | while ( i.hasTerms() && ! result.isOne() ) |
---|
| 701 | { |
---|
[a7ec94] | 702 | result = gcd( i.coeff(), result ); |
---|
[150dc8] | 703 | i++; |
---|
| 704 | } |
---|
| 705 | return result; |
---|
[9bab9f] | 706 | } |
---|
| 707 | else |
---|
[a7ec94] | 708 | return abs( f ); |
---|
[9bab9f] | 709 | } |
---|
[dd3e561] | 710 | //}}} |
---|
[9bab9f] | 711 | |
---|
[4ea0ab] | 712 | //{{{ CanonicalForm content ( const CanonicalForm & f ) |
---|
| 713 | //{{{ docu |
---|
| 714 | // |
---|
| 715 | // content() - return content(f) with respect to main variable. |
---|
| 716 | // |
---|
[dd3e561] | 717 | // Normalizes result. |
---|
| 718 | // |
---|
[4ea0ab] | 719 | //}}} |
---|
[9bab9f] | 720 | CanonicalForm |
---|
| 721 | content ( const CanonicalForm & f ) |
---|
| 722 | { |
---|
[6f62c3] | 723 | if ( f.inPolyDomain() || ( f.inExtension() && ! getReduce( f.mvar() ) ) ) |
---|
| 724 | { |
---|
[a7ec94] | 725 | CFIterator i = f; |
---|
| 726 | CanonicalForm result = abs( i.coeff() ); |
---|
| 727 | i++; |
---|
[6f62c3] | 728 | while ( i.hasTerms() && ! result.isOne() ) |
---|
| 729 | { |
---|
[a7ec94] | 730 | result = gcd( i.coeff(), result ); |
---|
| 731 | i++; |
---|
| 732 | } |
---|
| 733 | return result; |
---|
| 734 | } |
---|
| 735 | else |
---|
| 736 | return abs( f ); |
---|
[9bab9f] | 737 | } |
---|
[4ea0ab] | 738 | //}}} |
---|
[9bab9f] | 739 | |
---|
[dd3e561] | 740 | //{{{ CanonicalForm content ( const CanonicalForm & f, const Variable & x ) |
---|
| 741 | //{{{ docu |
---|
| 742 | // |
---|
| 743 | // content() - return content(f) with respect to x. |
---|
| 744 | // |
---|
| 745 | // x should be a polynomial variable. |
---|
| 746 | // |
---|
| 747 | //}}} |
---|
[9bab9f] | 748 | CanonicalForm |
---|
| 749 | content ( const CanonicalForm & f, const Variable & x ) |
---|
| 750 | { |
---|
[dd3e561] | 751 | ASSERT( x.level() > 0, "cannot calculate content with respect to algebraic variable" ); |
---|
| 752 | Variable y = f.mvar(); |
---|
| 753 | |
---|
| 754 | if ( y == x ) |
---|
[150dc8] | 755 | return cf_content( f, 0 ); |
---|
[dd3e561] | 756 | else if ( y < x ) |
---|
[150dc8] | 757 | return f; |
---|
[9bab9f] | 758 | else |
---|
[150dc8] | 759 | return swapvar( content( swapvar( f, y, x ), y ), y, x ); |
---|
[9bab9f] | 760 | } |
---|
[dd3e561] | 761 | //}}} |
---|
[9bab9f] | 762 | |
---|
[dd3e561] | 763 | //{{{ CanonicalForm vcontent ( const CanonicalForm & f, const Variable & x ) |
---|
| 764 | //{{{ docu |
---|
| 765 | // |
---|
| 766 | // vcontent() - return content of f with repect to variables >= x. |
---|
| 767 | // |
---|
| 768 | // The content is recursively calculated over all coefficients in |
---|
| 769 | // f having level less than x. x should be a polynomial |
---|
| 770 | // variable. |
---|
| 771 | // |
---|
| 772 | //}}} |
---|
[9bab9f] | 773 | CanonicalForm |
---|
| 774 | vcontent ( const CanonicalForm & f, const Variable & x ) |
---|
| 775 | { |
---|
[dd3e561] | 776 | ASSERT( x.level() > 0, "cannot calculate vcontent with respect to algebraic variable" ); |
---|
| 777 | |
---|
[9bab9f] | 778 | if ( f.mvar() <= x ) |
---|
[150dc8] | 779 | return content( f, x ); |
---|
[9bab9f] | 780 | else { |
---|
[150dc8] | 781 | CFIterator i; |
---|
| 782 | CanonicalForm d = 0; |
---|
| 783 | for ( i = f; i.hasTerms() && ! d.isOne(); i++ ) |
---|
| 784 | d = gcd( d, vcontent( i.coeff(), x ) ); |
---|
| 785 | return d; |
---|
[9bab9f] | 786 | } |
---|
| 787 | } |
---|
[dd3e561] | 788 | //}}} |
---|
[9bab9f] | 789 | |
---|
[4ea0ab] | 790 | //{{{ CanonicalForm pp ( const CanonicalForm & f ) |
---|
| 791 | //{{{ docu |
---|
| 792 | // |
---|
| 793 | // pp() - return primitive part of f. |
---|
| 794 | // |
---|
[dd3e561] | 795 | // Returns zero if f equals zero, otherwise f / content(f). |
---|
| 796 | // |
---|
[4ea0ab] | 797 | //}}} |
---|
[9bab9f] | 798 | CanonicalForm |
---|
| 799 | pp ( const CanonicalForm & f ) |
---|
| 800 | { |
---|
| 801 | if ( f.isZero() ) |
---|
[150dc8] | 802 | return f; |
---|
[9bab9f] | 803 | else |
---|
[150dc8] | 804 | return f / content( f ); |
---|
[9bab9f] | 805 | } |
---|
[4ea0ab] | 806 | //}}} |
---|
[9bab9f] | 807 | |
---|
[ff6222] | 808 | CanonicalForm |
---|
[9bab9f] | 809 | gcd ( const CanonicalForm & f, const CanonicalForm & g ) |
---|
| 810 | { |
---|
[a7ec94] | 811 | bool b = f.isZero(); |
---|
| 812 | if ( b || g.isZero() ) |
---|
| 813 | { |
---|
| 814 | if ( b ) |
---|
| 815 | return abs( g ); |
---|
[abfc3b] | 816 | else |
---|
[a7ec94] | 817 | return abs( f ); |
---|
| 818 | } |
---|
| 819 | if ( f.inPolyDomain() || g.inPolyDomain() ) |
---|
| 820 | { |
---|
| 821 | if ( f.mvar() != g.mvar() ) |
---|
| 822 | { |
---|
| 823 | if ( f.mvar() > g.mvar() ) |
---|
| 824 | return cf_content( f, g ); |
---|
| 825 | else |
---|
| 826 | return cf_content( g, f ); |
---|
| 827 | } |
---|
[bb82f0] | 828 | if (isOn(SW_USE_QGCD)) |
---|
| 829 | { |
---|
| 830 | Variable m; |
---|
[fc9f44] | 831 | if ( |
---|
| 832 | (getCharacteristic() == 0) && |
---|
[e6f7ee1] | 833 | (hasFirstAlgVar(f,m) || hasFirstAlgVar(g,m)) |
---|
[bb82f0] | 834 | //&& f.isUnivariate() |
---|
| 835 | //&& g.isUnivariate() |
---|
| 836 | ) |
---|
[fc31bce] | 837 | { |
---|
[ad8e1b] | 838 | //if ((f.level()==g.level()) && f.isUnivariate() && g.isUnivariate()) |
---|
| 839 | // return univarQGCD(f,g); |
---|
| 840 | //else |
---|
[713bdb] | 841 | //return QGCD(f,g); |
---|
| 842 | bool on_rational = isOn(SW_RATIONAL); |
---|
| 843 | CanonicalForm r=QGCD(f,g); |
---|
[f06059] | 844 | On(SW_RATIONAL); |
---|
[713bdb] | 845 | CanonicalForm cdF = bCommonDen( r ); |
---|
| 846 | if (!on_rational) Off(SW_RATIONAL); |
---|
| 847 | return cdF*r; |
---|
[fc31bce] | 848 | } |
---|
[bb82f0] | 849 | } |
---|
[713bdb] | 850 | |
---|
[150dc8] | 851 | if ( f.inExtension() && getReduce( f.mvar() ) ) |
---|
[bb82f0] | 852 | return CanonicalForm(1); |
---|
[a7ec94] | 853 | else |
---|
| 854 | { |
---|
[ebc602] | 855 | if ( fdivides( f, g ) ) |
---|
[a7ec94] | 856 | return abs( f ); |
---|
[ebc602] | 857 | else if ( fdivides( g, f ) ) |
---|
[a7ec94] | 858 | return abs( g ); |
---|
| 859 | if ( !( getCharacteristic() == 0 && isOn( SW_RATIONAL ) ) ) |
---|
| 860 | { |
---|
| 861 | CanonicalForm d; |
---|
[5944b4] | 862 | #if 1 |
---|
[a7ec94] | 863 | do{ d = gcd_poly( f, g ); } |
---|
[ebc602] | 864 | while ((!fdivides(d,f)) || (!fdivides(d,g))); |
---|
[5944b4] | 865 | #else |
---|
| 866 | while(1) |
---|
[f4b180] | 867 | { |
---|
| 868 | d = gcd_poly( f, g ); |
---|
[5944b4] | 869 | if ((fdivides(d,f)) && (fdivides(d,g))) break; |
---|
| 870 | printf("g"); fflush(stdout); |
---|
| 871 | } |
---|
| 872 | #endif |
---|
[a7ec94] | 873 | return abs( d ); |
---|
| 874 | } |
---|
| 875 | else |
---|
| 876 | { |
---|
[150dc8] | 877 | CanonicalForm cdF = bCommonDen( f ); |
---|
| 878 | CanonicalForm cdG = bCommonDen( g ); |
---|
| 879 | Off( SW_RATIONAL ); |
---|
| 880 | CanonicalForm l = lcm( cdF, cdG ); |
---|
| 881 | On( SW_RATIONAL ); |
---|
| 882 | CanonicalForm F = f * l, G = g * l; |
---|
| 883 | Off( SW_RATIONAL ); |
---|
[a7ec94] | 884 | do { l = gcd_poly( F, G ); } |
---|
[ebc602] | 885 | while ((!fdivides(l,F)) || (!fdivides(l,G))); |
---|
[150dc8] | 886 | On( SW_RATIONAL ); |
---|
[a7ec94] | 887 | return abs( l ); |
---|
[150dc8] | 888 | } |
---|
| 889 | } |
---|
[a7ec94] | 890 | } |
---|
| 891 | if ( f.inBaseDomain() && g.inBaseDomain() ) |
---|
| 892 | return bgcd( f, g ); |
---|
[9bab9f] | 893 | else |
---|
[a7ec94] | 894 | return 1; |
---|
[9bab9f] | 895 | } |
---|
| 896 | |
---|
[dd3e561] | 897 | //{{{ CanonicalForm lcm ( const CanonicalForm & f, const CanonicalForm & g ) |
---|
| 898 | //{{{ docu |
---|
| 899 | // |
---|
| 900 | // lcm() - return least common multiple of f and g. |
---|
| 901 | // |
---|
| 902 | // The lcm is calculated using the formula lcm(f, g) = f * g / gcd(f, g). |
---|
| 903 | // |
---|
| 904 | // Returns zero if one of f or g equals zero. |
---|
| 905 | // |
---|
| 906 | //}}} |
---|
[9bab9f] | 907 | CanonicalForm |
---|
| 908 | lcm ( const CanonicalForm & f, const CanonicalForm & g ) |
---|
| 909 | { |
---|
[dd3e561] | 910 | if ( f.isZero() || g.isZero() ) |
---|
[a7ec94] | 911 | return 0; |
---|
[dd3e561] | 912 | else |
---|
[150dc8] | 913 | return ( f / gcd( f, g ) ) * g; |
---|
[9bab9f] | 914 | } |
---|
[dd3e561] | 915 | //}}} |
---|
[a7ec94] | 916 | |
---|
| 917 | #ifdef HAVE_NTL |
---|
| 918 | |
---|
| 919 | static CanonicalForm |
---|
| 920 | gcd_univar_ntl0( const CanonicalForm & F, const CanonicalForm & G ) |
---|
| 921 | { |
---|
| 922 | ZZX F1=convertFacCF2NTLZZX(F); |
---|
| 923 | ZZX G1=convertFacCF2NTLZZX(G); |
---|
| 924 | ZZX R=GCD(F1,G1); |
---|
| 925 | return convertNTLZZX2CF(R,F.mvar()); |
---|
| 926 | } |
---|
| 927 | |
---|
[c4f4fd] | 928 | static CanonicalForm |
---|
| 929 | gcd_univar_ntlp( const CanonicalForm & F, const CanonicalForm & G ) |
---|
| 930 | { |
---|
| 931 | if (fac_NTL_char!=getCharacteristic()) |
---|
| 932 | { |
---|
| 933 | fac_NTL_char=getCharacteristic(); |
---|
| 934 | #ifdef NTL_ZZ |
---|
| 935 | ZZ r; |
---|
| 936 | r=getCharacteristic(); |
---|
| 937 | ZZ_pContext ccc(r); |
---|
| 938 | #else |
---|
| 939 | zz_pContext ccc(getCharacteristic()); |
---|
| 940 | #endif |
---|
| 941 | ccc.restore(); |
---|
| 942 | #ifdef NTL_ZZ |
---|
| 943 | ZZ_p::init(r); |
---|
| 944 | #else |
---|
| 945 | zz_p::init(getCharacteristic()); |
---|
| 946 | #endif |
---|
| 947 | } |
---|
| 948 | #ifdef NTL_ZZ |
---|
| 949 | ZZ_pX F1=convertFacCF2NTLZZpX(F); |
---|
| 950 | ZZ_pX G1=convertFacCF2NTLZZpX(G); |
---|
| 951 | ZZ_pX R=GCD(F1,G1); |
---|
| 952 | return convertNTLZZpX2CF(R,F.mvar()); |
---|
| 953 | #else |
---|
| 954 | zz_pX F1=convertFacCF2NTLzzpX(F); |
---|
| 955 | zz_pX G1=convertFacCF2NTLzzpX(G); |
---|
| 956 | zz_pX R=GCD(F1,G1); |
---|
| 957 | return convertNTLzzpX2CF(R,F.mvar()); |
---|
| 958 | #endif |
---|
| 959 | } |
---|
| 960 | |
---|
[a7ec94] | 961 | #endif |
---|
| 962 | |
---|
| 963 | static bool |
---|
| 964 | gcd_avoid_mtaildegree ( CanonicalForm & f1, CanonicalForm & g1, CanonicalForm & d1 ) |
---|
| 965 | { |
---|
| 966 | bool rdy = true; |
---|
| 967 | int df = f1.taildegree(); |
---|
| 968 | int dg = g1.taildegree(); |
---|
| 969 | |
---|
| 970 | d1 = d1.genOne(); |
---|
| 971 | if ( dg == 0 ) |
---|
| 972 | { |
---|
| 973 | if ( df == 0 ) |
---|
| 974 | return false; |
---|
| 975 | else |
---|
| 976 | { |
---|
| 977 | if ( f1.degree() == df ) |
---|
| 978 | d1 = cf_content( g1, LC( f1 ) ); |
---|
| 979 | else |
---|
| 980 | { |
---|
| 981 | f1 /= power( f1.mvar(), df ); |
---|
| 982 | rdy = false; |
---|
| 983 | } |
---|
| 984 | } |
---|
| 985 | } |
---|
| 986 | else |
---|
| 987 | { |
---|
| 988 | if ( df == 0) |
---|
| 989 | { |
---|
| 990 | if ( g1.degree() == dg ) |
---|
| 991 | d1 = cf_content( f1, LC( g1 ) ); |
---|
| 992 | else |
---|
| 993 | { |
---|
| 994 | g1 /= power( g1.mvar(), dg ); |
---|
| 995 | rdy = false; |
---|
| 996 | } |
---|
| 997 | } |
---|
| 998 | else |
---|
| 999 | { |
---|
| 1000 | if ( df > dg ) |
---|
| 1001 | d1 = power( f1.mvar(), dg ); |
---|
| 1002 | else |
---|
| 1003 | d1 = power( f1.mvar(), df ); |
---|
| 1004 | if ( f1.degree() == df ) |
---|
| 1005 | { |
---|
| 1006 | if (g1.degree() == dg) |
---|
| 1007 | d1 *= gcd( LC( f1 ), LC( g1 ) ); |
---|
| 1008 | else |
---|
| 1009 | { |
---|
| 1010 | g1 /= power( g1.mvar(), dg); |
---|
| 1011 | d1 *= cf_content( g1, LC( f1 ) ); |
---|
| 1012 | } |
---|
| 1013 | } |
---|
| 1014 | else |
---|
| 1015 | { |
---|
| 1016 | f1 /= power( f1.mvar(), df ); |
---|
| 1017 | if ( g1.degree() == dg ) |
---|
| 1018 | d1 *= cf_content( f1, LC( g1 ) ); |
---|
| 1019 | else |
---|
| 1020 | { |
---|
| 1021 | g1 /= power( g1.mvar(), dg ); |
---|
| 1022 | rdy = false; |
---|
| 1023 | } |
---|
| 1024 | } |
---|
| 1025 | } |
---|
| 1026 | } |
---|
| 1027 | return rdy; |
---|
| 1028 | } |
---|
| 1029 | |
---|
| 1030 | /* |
---|
| 1031 | * compute positions p1 and pe of optimal variables: |
---|
| 1032 | * pe is used in "ezgcd" and |
---|
| 1033 | * p1 in "gcd_poly1" |
---|
| 1034 | */ |
---|
| 1035 | static |
---|
| 1036 | void optvalues ( const int * df, const int * dg, const int n, int & p1, int &pe ) |
---|
| 1037 | { |
---|
| 1038 | int i, o1, oe; |
---|
| 1039 | if ( df[n] > dg[n] ) |
---|
| 1040 | { |
---|
| 1041 | o1 = df[n]; oe = dg[n]; |
---|
| 1042 | } |
---|
| 1043 | else |
---|
| 1044 | { |
---|
| 1045 | o1 = dg[n]; oe = df[n]; |
---|
| 1046 | } |
---|
| 1047 | i = n-1; |
---|
| 1048 | while ( i > 0 ) |
---|
| 1049 | { |
---|
| 1050 | if ( df[i] != 0 ) |
---|
| 1051 | { |
---|
| 1052 | if ( df[i] > dg[i] ) |
---|
| 1053 | { |
---|
| 1054 | if ( o1 > df[i]) { o1 = df[i]; p1 = i; } |
---|
| 1055 | if ( oe <= dg[i]) { oe = dg[i]; pe = i; } |
---|
| 1056 | } |
---|
| 1057 | else |
---|
| 1058 | { |
---|
| 1059 | if ( o1 > dg[i]) { o1 = dg[i]; p1 = i; } |
---|
| 1060 | if ( oe <= df[i]) { oe = df[i]; pe = i; } |
---|
| 1061 | } |
---|
| 1062 | } |
---|
| 1063 | i--; |
---|
| 1064 | } |
---|
| 1065 | } |
---|
| 1066 | |
---|
| 1067 | /* |
---|
| 1068 | * make some changes of variables, see optvalues |
---|
| 1069 | */ |
---|
| 1070 | static void |
---|
| 1071 | cf_prepgcd( const CanonicalForm & f, const CanonicalForm & g, int & cc, int & p1, int &pe ) |
---|
| 1072 | { |
---|
| 1073 | int i, k, n; |
---|
| 1074 | n = f.level(); |
---|
| 1075 | cc = 0; |
---|
| 1076 | p1 = pe = n; |
---|
| 1077 | if ( n == 1 ) |
---|
| 1078 | return; |
---|
| 1079 | int * degsf = new int[n+1]; |
---|
| 1080 | int * degsg = new int[n+1]; |
---|
| 1081 | for ( i = n; i > 0; i-- ) |
---|
| 1082 | { |
---|
| 1083 | degsf[i] = degsg[i] = 0; |
---|
| 1084 | } |
---|
| 1085 | degsf = degrees( f, degsf ); |
---|
| 1086 | degsg = degrees( g, degsg ); |
---|
| 1087 | |
---|
| 1088 | k = 0; |
---|
| 1089 | for ( i = n-1; i > 0; i-- ) |
---|
| 1090 | { |
---|
[f4b180] | 1091 | if ( degsf[i] == 0 ) |
---|
[a7ec94] | 1092 | { |
---|
| 1093 | if ( degsg[i] != 0 ) |
---|
| 1094 | { |
---|
| 1095 | cc = -i; |
---|
| 1096 | break; |
---|
| 1097 | } |
---|
| 1098 | } |
---|
| 1099 | else |
---|
| 1100 | { |
---|
| 1101 | if ( degsg[i] == 0 ) |
---|
| 1102 | { |
---|
| 1103 | cc = i; |
---|
| 1104 | break; |
---|
| 1105 | } |
---|
| 1106 | else k++; |
---|
| 1107 | } |
---|
| 1108 | } |
---|
| 1109 | |
---|
| 1110 | if ( ( cc == 0 ) && ( k != 0 ) ) |
---|
| 1111 | optvalues( degsf, degsg, n, p1, pe ); |
---|
| 1112 | if ( ( pe != 1 ) && ( degsf[1] != 0 ) ) |
---|
| 1113 | pe = -pe; |
---|
[f4b180] | 1114 | |
---|
[a7ec94] | 1115 | delete [] degsf; |
---|
| 1116 | delete [] degsg; |
---|
| 1117 | } |
---|
[6f62c3] | 1118 | |
---|
| 1119 | |
---|
| 1120 | static CanonicalForm |
---|
| 1121 | balance_p ( const CanonicalForm & f, const CanonicalForm & q ) |
---|
| 1122 | { |
---|
| 1123 | Variable x = f.mvar(); |
---|
| 1124 | CanonicalForm result = 0, qh = q / 2; |
---|
| 1125 | CanonicalForm c; |
---|
| 1126 | CFIterator i; |
---|
| 1127 | for ( i = f; i.hasTerms(); i++ ) |
---|
| 1128 | { |
---|
| 1129 | c = i.coeff(); |
---|
| 1130 | if ( c.inCoeffDomain()) |
---|
| 1131 | { |
---|
| 1132 | if ( c > qh ) |
---|
| 1133 | result += power( x, i.exp() ) * (c - q); |
---|
| 1134 | else |
---|
| 1135 | result += power( x, i.exp() ) * c; |
---|
| 1136 | } |
---|
[f4b180] | 1137 | else |
---|
[6f62c3] | 1138 | result += power( x, i.exp() ) * balance_p(c,q); |
---|
| 1139 | } |
---|
| 1140 | return result; |
---|
| 1141 | } |
---|
| 1142 | |
---|
| 1143 | CanonicalForm chinrem_gcd ( const CanonicalForm & FF, const CanonicalForm & GG ) |
---|
| 1144 | { |
---|
[01e8874] | 1145 | CanonicalForm f, g, cg, cl, q(0), Dp, newD, D, newq; |
---|
| 1146 | int p, i, dp_deg, d_deg; |
---|
[6f62c3] | 1147 | |
---|
[01e8874] | 1148 | CanonicalForm cd ( bCommonDen( FF )); |
---|
[6f62c3] | 1149 | f=cd*FF; |
---|
| 1150 | f /=vcontent(f,Variable(1)); |
---|
[08a6ebb] | 1151 | //cd = bCommonDen( f ); f *=cd; |
---|
| 1152 | //f /=vcontent(f,Variable(1)); |
---|
[6f62c3] | 1153 | |
---|
| 1154 | cd = bCommonDen( GG ); |
---|
| 1155 | g=cd*GG; |
---|
| 1156 | g /=vcontent(g,Variable(1)); |
---|
[08a6ebb] | 1157 | //cd = bCommonDen( g ); g *=cd; |
---|
| 1158 | //g /=vcontent(g,Variable(1)); |
---|
[6f62c3] | 1159 | |
---|
| 1160 | i = cf_getNumBigPrimes() - 1; |
---|
| 1161 | cl = f.lc()* g.lc(); |
---|
| 1162 | |
---|
| 1163 | while ( true ) |
---|
| 1164 | { |
---|
| 1165 | p = cf_getBigPrime( i ); |
---|
| 1166 | i--; |
---|
| 1167 | while ( i >= 0 && mod( cl, p ) == 0 ) |
---|
| 1168 | { |
---|
| 1169 | p = cf_getBigPrime( i ); |
---|
| 1170 | i--; |
---|
| 1171 | } |
---|
[c30347] | 1172 | //printf("try p=%d\n",p); |
---|
[6f62c3] | 1173 | setCharacteristic( p ); |
---|
[c30347] | 1174 | Dp = gcd_poly( mapinto( f ), mapinto( g ) ); |
---|
[08a6ebb] | 1175 | Dp /=Dp.lc(); |
---|
[6f62c3] | 1176 | setCharacteristic( 0 ); |
---|
| 1177 | dp_deg=totaldegree(Dp); |
---|
| 1178 | if ( dp_deg == 0 ) |
---|
[c30347] | 1179 | { |
---|
| 1180 | //printf(" -> 1\n"); |
---|
[6f62c3] | 1181 | return CanonicalForm(1); |
---|
[c30347] | 1182 | } |
---|
[6f62c3] | 1183 | if ( q.isZero() ) |
---|
| 1184 | { |
---|
| 1185 | D = mapinto( Dp ); |
---|
| 1186 | d_deg=dp_deg; |
---|
| 1187 | q = p; |
---|
| 1188 | } |
---|
| 1189 | else |
---|
| 1190 | { |
---|
| 1191 | if ( dp_deg == d_deg ) |
---|
| 1192 | { |
---|
| 1193 | chineseRemainder( D, q, mapinto( Dp ), p, newD, newq ); |
---|
| 1194 | q = newq; |
---|
| 1195 | D = newD; |
---|
| 1196 | } |
---|
[f4b180] | 1197 | else if ( dp_deg < d_deg ) |
---|
[6f62c3] | 1198 | { |
---|
[c30347] | 1199 | //printf(" were all bad, try more\n"); |
---|
[6f62c3] | 1200 | // all previous p's are bad primes |
---|
| 1201 | q = p; |
---|
| 1202 | D = mapinto( Dp ); |
---|
| 1203 | d_deg=dp_deg; |
---|
| 1204 | } |
---|
[c30347] | 1205 | else |
---|
| 1206 | { |
---|
| 1207 | //printf(" was bad, try more\n"); |
---|
| 1208 | } |
---|
[f4b180] | 1209 | //else dp_deg > d_deg: bad prime |
---|
[6f62c3] | 1210 | } |
---|
[08a6ebb] | 1211 | if ( i >= 0 ) |
---|
[6f62c3] | 1212 | { |
---|
[c992ec1] | 1213 | CanonicalForm Dn= Farey(D,q); |
---|
| 1214 | int is_rat=isOn(SW_RATIONAL); |
---|
| 1215 | On(SW_RATIONAL); |
---|
| 1216 | CanonicalForm cd = bCommonDen( Dn ); // we need On(SW_RATIONAL) |
---|
| 1217 | if (!is_rat) Off(SW_RATIONAL); |
---|
| 1218 | Dn *=cd; |
---|
| 1219 | //Dn /=vcontent(Dn,Variable(1)); |
---|
| 1220 | if ( fdivides( Dn, f ) && fdivides( Dn, g ) ) |
---|
[6f62c3] | 1221 | { |
---|
[c30347] | 1222 | //printf(" -> success\n"); |
---|
[c992ec1] | 1223 | return Dn; |
---|
[6f62c3] | 1224 | } |
---|
[c992ec1] | 1225 | //else: try more primes |
---|
[6f62c3] | 1226 | } |
---|
| 1227 | else |
---|
[c992ec1] | 1228 | { // try other method |
---|
[c30347] | 1229 | //printf("try other gcd\n"); |
---|
[6f62c3] | 1230 | Off(SW_USE_CHINREM_GCD); |
---|
| 1231 | D=gcd_poly( f, g ); |
---|
| 1232 | On(SW_USE_CHINREM_GCD); |
---|
| 1233 | return D; |
---|
| 1234 | } |
---|
| 1235 | } |
---|
| 1236 | } |
---|
[c5d0aed] | 1237 | |
---|
[bb82f0] | 1238 | #include "algext.cc" |
---|
[c5d0aed] | 1239 | |
---|