[35aab3] | 1 | // emacs edit mode for this file is -*- C++ -*- |
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[341696] | 2 | // $Id$ |
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[35aab3] | 3 | |
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| 4 | /**************************************** |
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| 5 | * Computer Algebra System SINGULAR * |
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| 6 | ****************************************/ |
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| 7 | /* |
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| 8 | * ABSTRACT - class gaussReducer. Used in fglmzero.cc and fglmhom.cc |
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| 9 | * to find linear dependecies of fglmVectors. |
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| 10 | */ |
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| 11 | |
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[599326] | 12 | #include <kernel/mod2.h> |
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[35aab3] | 13 | |
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| 14 | #ifdef HAVE_FACTORY |
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[599326] | 15 | #include <kernel/structs.h> |
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| 16 | #include <kernel/numbers.h> |
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| 17 | #include <kernel/ring.h> |
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[b1dfaf] | 18 | #include <omalloc/omalloc.h> |
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[35aab3] | 19 | |
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[599326] | 20 | #include <kernel/fglmvec.h> |
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| 21 | #include <kernel/fglmgauss.h> |
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[35aab3] | 22 | |
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| 23 | class gaussElem |
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| 24 | { |
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| 25 | public: |
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| 26 | fglmVector v; |
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| 27 | fglmVector p; |
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| 28 | number pdenom; |
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| 29 | number fac; |
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| 30 | gaussElem( const fglmVector newv, const fglmVector newp, number & newpdenom, number & newfac ) : v( newv ), p( newp ), pdenom( newpdenom ), fac( newfac ) |
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| 31 | { |
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| 32 | newpdenom= NULL; |
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| 33 | newfac= NULL; |
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| 34 | } |
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| 35 | |
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| 36 | #ifndef HAVE_EXPLICIT_CONSTR |
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| 37 | gaussElem() : v(), p(), pdenom(NULL), fac(NULL) {} |
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| 38 | |
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| 39 | void mac_gaussElem( const fglmVector newv, const fglmVector newp, number & newpdenom, number & newfac ) |
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| 40 | { |
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| 41 | v= newv; |
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| 42 | p= newp; |
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| 43 | pdenom=newpdenom; |
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| 44 | fac=newfac; |
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| 45 | newpdenom= NULL; |
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| 46 | newfac= NULL; |
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| 47 | } |
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| 48 | #endif |
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| 49 | |
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| 50 | ~gaussElem() |
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| 51 | { |
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| 52 | nDelete( & pdenom ); |
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| 53 | nDelete( & fac ); |
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| 54 | } |
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| 55 | }; |
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| 56 | |
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| 57 | gaussReducer::gaussReducer( int dimen ) |
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| 58 | { |
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| 59 | int k; |
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| 60 | size= 0; |
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| 61 | max= dimen; |
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| 62 | #ifndef HAVE_EXPLICIT_CONSTR |
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| 63 | elems= new gaussElem[ max+1 ]; |
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| 64 | #else |
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| 65 | elems= (gaussElem *)omAlloc( (max+1)*sizeof( gaussElem ) ); |
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| 66 | #endif |
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| 67 | isPivot= (BOOLEAN *)omAlloc( (max+1)*sizeof( BOOLEAN ) ); |
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| 68 | for ( k= max; k > 0; k-- ) |
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| 69 | isPivot[k]= FALSE; |
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| 70 | perm= (int *)omAlloc( (max+1)*sizeof( int ) ); |
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| 71 | } |
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| 72 | |
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| 73 | gaussReducer::~gaussReducer() |
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| 74 | { |
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| 75 | int k; |
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| 76 | |
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| 77 | #ifndef HAVE_EXPLICIT_CONSTR |
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| 78 | delete [] elems; |
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| 79 | #else |
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| 80 | for ( k= size; k > 0; k-- ) |
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| 81 | elems[k].~gaussElem(); |
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| 82 | omFreeSize( (ADDRESS)elems, (max+1)*sizeof( gaussElem ) ); |
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| 83 | #endif |
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| 84 | |
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| 85 | omFreeSize( (ADDRESS)isPivot, (max+1)*sizeof( BOOLEAN ) ); |
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| 86 | omFreeSize( (ADDRESS)perm, (max+1)*sizeof( int ) ); |
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| 87 | } |
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| 88 | |
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| 89 | BOOLEAN |
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| 90 | gaussReducer::reduce( fglmVector thev ) |
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| 91 | { |
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| 92 | number fac1, fac2; |
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| 93 | number temp; |
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| 94 | // Hier ueberlegen, ob thev als referenz, oder wie wann was kopiert usw. |
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| 95 | v= thev; |
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| 96 | p= fglmVector( size + 1, size + 1 ); |
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| 97 | // fglmASSERT( pdenom == NULL ); |
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| 98 | pdenom= nInit( 1 ); |
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| 99 | number vdenom = v.clearDenom(); |
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| 100 | if ( ! nIsOne( vdenom ) && ! nIsZero( vdenom ) ) { |
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| 101 | p.setelem( p.size(), vdenom ); |
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| 102 | } |
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| 103 | else { |
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| 104 | nDelete( & vdenom ); |
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| 105 | } |
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| 106 | number gcd = v.gcd(); |
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| 107 | if ( ! nIsOne( gcd ) && ! nIsZero( gcd ) ) { |
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| 108 | v /= gcd; |
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| 109 | number temp= nMult( pdenom, gcd ); |
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| 110 | nDelete( & pdenom ); |
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| 111 | pdenom= temp; |
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| 112 | } |
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| 113 | nDelete( & gcd ); |
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| 114 | |
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| 115 | int k; |
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| 116 | for ( k= 1; k <= size; k++ ) { |
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| 117 | if ( ! v.elemIsZero( perm[k] ) ) { |
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| 118 | fac1= elems[k].fac; |
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| 119 | fac2= nCopy( v.getconstelem( perm[k] ) ); |
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| 120 | v.nihilate( fac1, fac2, elems[k].v ); |
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| 121 | fac1= nMult( fac1, elems[k].pdenom ); |
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| 122 | temp= nMult( fac2, pdenom ); |
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| 123 | nDelete( & fac2 ); |
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| 124 | fac2= temp; |
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| 125 | p.nihilate( fac1, fac2, elems[k].p ); |
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| 126 | temp= nMult( pdenom, elems[k].pdenom ); |
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| 127 | nDelete( & pdenom ); |
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| 128 | pdenom= temp; |
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| 129 | |
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| 130 | nDelete( & fac1 ); |
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| 131 | nDelete( & fac2 ); |
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| 132 | number gcd = v.gcd(); |
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| 133 | if ( ! nIsOne( gcd ) && ! nIsZero( gcd ) ) { |
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| 134 | v/= gcd; |
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| 135 | number temp = nMult( pdenom, gcd ); |
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| 136 | nDelete( & pdenom ); |
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| 137 | pdenom= temp; |
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| 138 | } |
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| 139 | nDelete( & gcd ); |
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| 140 | gcd= p.gcd(); |
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| 141 | temp= nGcd( pdenom, gcd, currRing ); |
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| 142 | nDelete( & gcd ); |
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| 143 | gcd= temp; |
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| 144 | if ( ! nIsZero( gcd ) && ! nIsOne( gcd ) ) { |
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| 145 | p/= gcd; |
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| 146 | temp= nDiv( pdenom, gcd ); |
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| 147 | nDelete( & pdenom ); |
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| 148 | pdenom= temp; |
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| 149 | nNormalize( pdenom ); |
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| 150 | } |
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| 151 | nDelete( & gcd ); |
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| 152 | } |
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| 153 | } |
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| 154 | return ( v.isZero() ); |
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| 155 | } |
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| 156 | |
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| 157 | void |
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| 158 | gaussReducer::store() |
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| 159 | { |
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| 160 | // fglmASSERT( size < max ); |
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| 161 | number fac; |
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| 162 | // find the pivot-element in v: |
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| 163 | |
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| 164 | size++; |
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| 165 | int k= 1; |
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| 166 | while ( nIsZero(v.getconstelem(k)) || isPivot[k] ) { |
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| 167 | k++; |
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| 168 | } |
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| 169 | // fglmASSERT( k <= dimen, "Error(1) in fglmDdata::pivot-search"); |
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| 170 | number pivot= v.getconstelem( k ); |
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| 171 | int pivotcol = k; |
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| 172 | k++; |
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| 173 | while ( k <= max ) { |
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| 174 | if ( ! nIsZero( v.getconstelem(k) ) && ! isPivot[k] ) { |
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| 175 | if ( nGreater( v.getconstelem( k ), pivot ) ) { |
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| 176 | pivot= v.getconstelem( k ); |
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| 177 | pivotcol= k; |
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| 178 | } |
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| 179 | } |
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| 180 | k++; |
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| 181 | } |
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| 182 | // fglmASSERT( ! nIsZero( pivot ), "Error(2) fglmDdata::Pivotelement ist Null" ); |
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| 183 | isPivot[ pivotcol ]= TRUE; |
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| 184 | perm[size]= pivotcol; |
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| 185 | |
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| 186 | pivot= nCopy( v.getconstelem( pivotcol ) ); |
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| 187 | #ifndef HAVE_EXPLICIT_CONSTR |
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| 188 | elems[size].mac_gaussElem( v, p, pdenom, pivot ); |
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| 189 | #else |
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| 190 | elems[size].gaussElem( v, p, pdenom, pivot ); |
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| 191 | #endif |
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| 192 | } |
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| 193 | |
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| 194 | fglmVector |
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| 195 | gaussReducer::getDependence() |
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| 196 | { |
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| 197 | nDelete( & pdenom ); |
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| 198 | // hier kann p noch gekuerzt werden, je nach Charakteristik |
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| 199 | fglmVector result = p; |
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| 200 | p= fglmVector(); |
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| 201 | return ( result ); |
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| 202 | } |
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| 203 | // ================================================================================ |
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| 204 | |
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| 205 | // ---------------------------------------------------------------------------- |
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| 206 | // Local Variables: *** |
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| 207 | // compile-command: "make Singular" *** |
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| 208 | // page-delimiter: "^\\(\\|//!\\)" *** |
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| 209 | // fold-internal-margins: nil *** |
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| 210 | // End: *** |
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| 211 | #endif // HAVE_FACTORY |
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