1 | #include <utility> |
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2 | |
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3 | #include <kernel/GBEngine/kstd1.h> |
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4 | #include <kernel/ideals.h> |
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5 | #include <Singular/ipid.h> |
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6 | |
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7 | #include <libpolys/polys/monomials/p_polys.h> |
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8 | #include <libpolys/polys/monomials/ring.h> |
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9 | #include <libpolys/polys/prCopy.h> |
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10 | |
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11 | #include <gfanlib/gfanlib.h> |
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12 | #include <gfanlib/gfanlib_matrix.h> |
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13 | |
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14 | #include <tropicalStrategy.h> |
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15 | #include <groebnerCone.h> |
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16 | #include <callgfanlib_conversion.h> |
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17 | #include <containsMonomial.h> |
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18 | #include <initial.h> |
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19 | #include <flip.h> |
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20 | #include <tropicalCurves.h> |
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21 | #include <bbcone.h> |
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22 | |
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23 | static bool checkPolynomialInput(const ideal I, const ring r) |
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24 | { |
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25 | if (r) rTest(r); |
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26 | if (I && r) id_Test(I,r); |
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27 | return ((!I) || (I && r)); |
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28 | } |
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29 | |
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30 | static bool checkOrderingAndCone(const ring r, const gfan::ZCone zc) |
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31 | { |
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32 | if (r) |
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33 | { |
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34 | int n = rVar(r); int* w = r->wvhdl[0]; |
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35 | gfan::ZVector v = wvhdlEntryToZVector(n,w); |
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36 | if (r->order[0]==ringorder_ws) |
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37 | v = gfan::Integer((long)-1)*v; |
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38 | if (!zc.contains(v)) |
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39 | { |
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40 | std::cout << "ERROR: weight of ordering not inside Groebner cone!" << std::endl |
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41 | << "cone: " << std::endl |
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42 | << toString(&zc) |
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43 | << "weight: " << std::endl |
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44 | << v << std::endl; |
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45 | return false; |
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46 | } |
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47 | return true; |
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48 | } |
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49 | return (zc.dimension()==0); |
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50 | } |
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51 | |
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52 | static bool checkPolyhedralInput(const gfan::ZCone zc, const gfan::ZVector p) |
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53 | { |
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54 | return zc.containsRelatively(p); |
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55 | } |
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56 | |
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57 | groebnerCone::groebnerCone(): |
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58 | polynomialIdeal(NULL), |
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59 | polynomialRing(NULL), |
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60 | polyhedralCone(gfan::ZCone(0)), |
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61 | interiorPoint(gfan::ZVector(0)), |
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62 | currentStrategy(NULL) |
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63 | { |
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64 | } |
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65 | |
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66 | groebnerCone::groebnerCone(const ideal I, const ring r, const tropicalStrategy& currentCase): |
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67 | polynomialIdeal(NULL), |
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68 | polynomialRing(NULL), |
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69 | currentStrategy(¤tCase) |
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70 | { |
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71 | assume(checkPolynomialInput(I,r)); |
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72 | if (I) polynomialIdeal = id_Copy(I,r); |
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73 | if (r) polynomialRing = rCopy(r); |
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74 | |
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75 | int n = rVar(polynomialRing); |
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76 | poly g = NULL; |
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77 | int* leadexpv = (int*) omAlloc((n+1)*sizeof(int)); |
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78 | int* tailexpv = (int*) omAlloc((n+1)*sizeof(int)); |
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79 | gfan::ZVector leadexpw = gfan::ZVector(n); |
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80 | gfan::ZVector tailexpw = gfan::ZVector(n); |
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81 | gfan::ZMatrix inequalities = gfan::ZMatrix(0,n); |
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82 | for (int i=0; i<idSize(polynomialIdeal); i++) |
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83 | { |
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84 | g = polynomialIdeal->m[i]; |
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85 | pGetExpV(g,leadexpv); |
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86 | leadexpw = intStar2ZVector(n, leadexpv); |
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87 | pIter(g); |
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88 | while (g) |
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89 | { |
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90 | pGetExpV(g,tailexpv); |
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91 | tailexpw = intStar2ZVector(n, tailexpv); |
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92 | inequalities.appendRow(leadexpw-tailexpw); |
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93 | pIter(g); |
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94 | } |
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95 | } |
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96 | omFreeSize(leadexpv,(n+1)*sizeof(int)); |
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97 | omFreeSize(tailexpv,(n+1)*sizeof(int)); |
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98 | polyhedralCone = gfan::ZCone(inequalities,gfan::ZMatrix(0, inequalities.getWidth())); |
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99 | interiorPoint = polyhedralCone.getRelativeInteriorPoint(); |
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100 | assume(checkOrderingAndCone(polynomialRing,polyhedralCone)); |
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101 | } |
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102 | |
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103 | static bool checkOrderingAndWeight(const ideal I, const ring r, const gfan::ZVector w, const tropicalStrategy& currentCase) |
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104 | { |
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105 | groebnerCone sigma(I,r,currentCase); |
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106 | gfan::ZCone zc = sigma.getPolyhedralCone(); |
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107 | return zc.contains(w); |
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108 | } |
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109 | |
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110 | groebnerCone::groebnerCone(const ideal I, const ring r, const gfan::ZVector& w, const tropicalStrategy& currentCase): |
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111 | polynomialIdeal(NULL), |
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112 | polynomialRing(NULL), |
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113 | currentStrategy(¤tCase) |
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114 | { |
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115 | assume(checkPolynomialInput(I,r)); |
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116 | if (I) polynomialIdeal = id_Copy(I,r); |
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117 | if (r) polynomialRing = rCopy(r); |
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118 | |
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119 | int n = rVar(r); |
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120 | gfan::ZMatrix inequalities = gfan::ZMatrix(0,n); |
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121 | gfan::ZMatrix equations = gfan::ZMatrix(0,n); |
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122 | int* expv = (int*) omAlloc((n+1)*sizeof(int)); |
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123 | for (int i=0; i<idSize(polynomialIdeal); i++) |
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124 | { |
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125 | poly g = polynomialIdeal->m[i]; |
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126 | p_GetExpV(g,expv,polynomialRing); |
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127 | gfan::ZVector leadexpv = intStar2ZVector(n,expv); |
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128 | long d = wDeg(g,polynomialRing,w); |
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129 | for (pIter(g); g; pIter(g)) |
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130 | { |
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131 | p_GetExpV(g,expv,polynomialRing); |
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132 | gfan::ZVector tailexpv = intStar2ZVector(n,expv); |
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133 | if (wDeg(g,polynomialRing,w)==d) |
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134 | equations.appendRow(leadexpv-tailexpv); |
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135 | else |
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136 | { |
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137 | assume(wDeg(g,polynomialRing,w)<d); |
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138 | inequalities.appendRow(leadexpv-tailexpv); |
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139 | } |
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140 | } |
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141 | } |
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142 | omFreeSize(expv,(n+1)*sizeof(int)); |
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143 | |
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144 | polyhedralCone = gfan::ZCone(inequalities,equations); |
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145 | interiorPoint = polyhedralCone.getRelativeInteriorPoint(); |
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146 | assume(checkOrderingAndCone(polynomialRing,polyhedralCone)); |
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147 | } |
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148 | |
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149 | /*** |
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150 | * Computes the groebner cone of I around u+e*w for e>0 sufficiently small. |
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151 | * Assumes that this cone is a face of the maximal Groenbner cone given by the ordering of r. |
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152 | **/ |
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153 | groebnerCone::groebnerCone(const ideal I, const ring r, const gfan::ZVector& u, const gfan::ZVector& w, const tropicalStrategy& currentCase): |
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154 | polynomialIdeal(NULL), |
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155 | polynomialRing(NULL), |
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156 | currentStrategy(¤tCase) |
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157 | { |
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158 | assume(checkPolynomialInput(I,r)); |
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159 | if (I) polynomialIdeal = id_Copy(I,r); |
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160 | if (r) polynomialRing = rCopy(r); |
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161 | |
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162 | int n = rVar(r); |
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163 | gfan::ZMatrix inequalities = gfan::ZMatrix(0,n); |
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164 | gfan::ZMatrix equations = gfan::ZMatrix(0,n); |
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165 | int* expv = (int*) omAlloc((n+1)*sizeof(int)); |
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166 | for (int i=0; i<idSize(polynomialIdeal); i++) |
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167 | { |
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168 | poly g = polynomialIdeal->m[i]; |
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169 | p_GetExpV(g,expv,polynomialRing); |
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170 | gfan::ZVector leadexpv = intStar2ZVector(n,expv); |
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171 | long d1 = wDeg(g,polynomialRing,u); |
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172 | long d2 = wDeg(g,polynomialRing,w); |
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173 | for (pIter(g); g; pIter(g)) |
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174 | { |
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175 | p_GetExpV(g,expv,polynomialRing); |
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176 | gfan::ZVector tailexpv = intStar2ZVector(n,expv); |
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177 | if (wDeg(g,polynomialRing,u)==d1 && wDeg(g,polynomialRing,w)==d2) |
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178 | equations.appendRow(leadexpv-tailexpv); |
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179 | else |
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180 | { |
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181 | assume(wDeg(g,polynomialRing,u)<d1 || wDeg(g,polynomialRing,w)<d2); |
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182 | inequalities.appendRow(leadexpv-tailexpv); |
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183 | } |
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184 | } |
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185 | } |
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186 | omFreeSize(expv,(n+1)*sizeof(int)); |
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187 | |
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188 | polyhedralCone = gfan::ZCone(inequalities,equations); |
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189 | interiorPoint = polyhedralCone.getRelativeInteriorPoint(); |
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190 | assume(checkOrderingAndCone(polynomialRing,polyhedralCone)); |
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191 | } |
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192 | |
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193 | |
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194 | groebnerCone::groebnerCone(const ideal I, const ideal inI, const ring r, const tropicalStrategy& currentCase): |
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195 | polynomialIdeal(id_Copy(I,r)), |
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196 | polynomialRing(rCopy(r)), |
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197 | currentStrategy(¤tCase) |
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198 | { |
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199 | assume(checkPolynomialInput(I,r)); |
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200 | assume(checkPolynomialInput(inI,r)); |
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201 | int n = rVar(r); |
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202 | gfan::ZMatrix equations = gfan::ZMatrix(0,n); |
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203 | int* expv = (int*) omAlloc((n+1)*sizeof(int)); |
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204 | for (int i=0; i<idSize(inI); i++) |
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205 | { |
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206 | poly g = inI->m[i]; |
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207 | p_GetExpV(g,expv,r); |
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208 | gfan::ZVector leadexpv = intStar2ZVector(n,expv); |
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209 | for (pIter(g); g; pIter(g)) |
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210 | { |
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211 | p_GetExpV(g,expv,r); |
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212 | gfan::ZVector tailexpv = intStar2ZVector(n,expv); |
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213 | equations.appendRow(leadexpv-tailexpv); |
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214 | } |
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215 | } |
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216 | gfan::ZMatrix inequalities = gfan::ZMatrix(0,n); |
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217 | for (int i=0; i<idSize(I); i++) |
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218 | { |
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219 | poly g = I->m[i]; |
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220 | p_GetExpV(g,expv,r); |
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221 | gfan::ZVector leadexpv = intStar2ZVector(n,expv); |
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222 | for (pIter(g); g; pIter(g)) |
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223 | { |
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224 | p_GetExpV(g,expv,r); |
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225 | gfan::ZVector tailexpv = intStar2ZVector(n,expv); |
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226 | inequalities.appendRow(leadexpv-tailexpv); |
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227 | } |
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228 | } |
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229 | omFreeSize(expv,(n+1)*sizeof(int)); |
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230 | |
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231 | polyhedralCone = gfan::ZCone(inequalities,equations); |
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232 | interiorPoint = polyhedralCone.getRelativeInteriorPoint(); |
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233 | assume(checkOrderingAndCone(polynomialRing,polyhedralCone)); |
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234 | } |
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235 | |
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236 | groebnerCone::groebnerCone(const groebnerCone &sigma): |
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237 | polynomialIdeal(NULL), |
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238 | polynomialRing(NULL), |
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239 | polyhedralCone(gfan::ZCone(sigma.getPolyhedralCone())), |
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240 | interiorPoint(gfan::ZVector(sigma.getInteriorPoint())), |
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241 | currentStrategy(sigma.getTropicalStrategy()) |
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242 | { |
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243 | assume(checkPolynomialInput(sigma.getPolynomialIdeal(),sigma.getPolynomialRing())); |
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244 | assume(checkOrderingAndCone(sigma.getPolynomialRing(),sigma.getPolyhedralCone())); |
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245 | assume(checkPolyhedralInput(sigma.getPolyhedralCone(),sigma.getInteriorPoint())); |
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246 | if (sigma.getPolynomialIdeal()) polynomialIdeal = id_Copy(sigma.getPolynomialIdeal(),sigma.getPolynomialRing()); |
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247 | if (sigma.getPolynomialRing()) polynomialRing = rCopy(sigma.getPolynomialRing()); |
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248 | } |
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249 | |
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250 | groebnerCone::~groebnerCone() |
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251 | { |
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252 | assume(checkPolynomialInput(polynomialIdeal,polynomialRing)); |
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253 | assume(checkOrderingAndCone(polynomialRing,polyhedralCone)); |
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254 | assume(checkPolyhedralInput(polyhedralCone,interiorPoint)); |
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255 | if (polynomialIdeal) id_Delete(&polynomialIdeal,polynomialRing); |
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256 | if (polynomialRing) rDelete(polynomialRing); |
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257 | } |
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258 | |
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259 | groebnerCone& groebnerCone::operator=(const groebnerCone& sigma) |
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260 | { |
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261 | assume(checkPolynomialInput(sigma.getPolynomialIdeal(),sigma.getPolynomialRing())); |
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262 | assume(checkOrderingAndCone(sigma.getPolynomialRing(),sigma.getPolyhedralCone())); |
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263 | assume(checkPolyhedralInput(sigma.getPolyhedralCone(),sigma.getInteriorPoint())); |
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264 | if (sigma.getPolynomialIdeal()) polynomialIdeal = id_Copy(sigma.getPolynomialIdeal(),sigma.getPolynomialRing()); |
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265 | if (sigma.getPolynomialRing()) polynomialRing = rCopy(sigma.getPolynomialRing()); |
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266 | polyhedralCone = sigma.getPolyhedralCone(); |
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267 | interiorPoint = sigma.getInteriorPoint(); |
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268 | currentStrategy = sigma.getTropicalStrategy(); |
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269 | return *this; |
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270 | } |
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271 | |
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272 | |
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273 | /*** |
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274 | * Returns a point in the tropical variety, if the groebnerCone contains one. |
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275 | * Returns an empty vector otherwise. |
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276 | **/ |
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277 | gfan::ZVector groebnerCone::tropicalPoint() const |
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278 | { |
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279 | ideal I = polynomialIdeal; |
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280 | ring r = polynomialRing; |
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281 | gfan::ZCone zc = polyhedralCone; |
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282 | gfan::ZMatrix R = zc.extremeRays(); |
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283 | assume(checkOrderingAndCone(r,zc)); |
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284 | for (int i=0; i<R.getHeight(); i++) |
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285 | { |
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286 | ideal inI = initial(I,r,R[i]); |
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287 | poly s = checkForMonomialViaSuddenSaturation(inI,r); |
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288 | if (s == NULL) |
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289 | { |
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290 | id_Delete(&inI,r); |
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291 | p_Delete(&s,r); |
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292 | return R[i]; |
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293 | } |
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294 | id_Delete(&inI,r); |
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295 | p_Delete(&s,r); |
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296 | } |
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297 | return gfan::ZVector(); |
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298 | } |
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299 | |
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300 | bool groebnerCone::checkFlipConeInput(const gfan::ZVector interiorPoint, const gfan::ZVector facetNormal) const |
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301 | { |
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302 | /* check first whether interiorPoint lies on the boundary of the cone */ |
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303 | if (!polyhedralCone.contains(interiorPoint)) |
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304 | { |
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305 | std::cout << "ERROR: interiorPoint is not contained in the Groebner cone!" << std::endl |
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306 | << "cone: " << std::endl |
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307 | << toString(&polyhedralCone) |
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308 | << "interiorPoint:" << std::endl |
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309 | << interiorPoint << std::endl; |
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310 | return false; |
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311 | } |
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312 | gfan::ZCone hopefullyAFacet = polyhedralCone.faceContaining(interiorPoint); |
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313 | if (hopefullyAFacet.dimension()!=(polyhedralCone.dimension()-1)) |
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314 | { |
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315 | std::cout << "ERROR: interiorPoint is not contained in the interior of a facet!" << std::endl |
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316 | << "cone: " << std::endl |
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317 | << toString(&polyhedralCone) |
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318 | << "interiorPoint:" << std::endl |
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319 | << interiorPoint << std::endl; |
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320 | return false; |
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321 | } |
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322 | /* check whether facet normal points outwards */ |
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323 | gfan::ZCone dual = polyhedralCone.dualCone(); |
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324 | if(dual.contains(facetNormal)) |
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325 | { |
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326 | std::cout << "ERROR: facetNormal is not pointing outwards!" << std::endl |
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327 | << "cone: " << std::endl |
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328 | << toString(&polyhedralCone) |
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329 | << "facetNormal:" << std::endl |
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330 | << facetNormal << std::endl; |
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331 | return false; |
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332 | } |
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333 | return true; |
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334 | } |
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335 | |
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336 | /*** |
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337 | * Given an interior point on the facet and the outer normal factor on the facet, |
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338 | * returns the adjacent groebnerCone sharing that facet |
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339 | **/ |
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340 | groebnerCone groebnerCone::flipCone(const gfan::ZVector interiorPoint, const gfan::ZVector facetNormal) const |
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341 | { |
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342 | assume(this->checkFlipConeInput(interiorPoint,facetNormal)); |
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343 | /* Note: the polynomial ring created will have a weighted ordering with respect to interiorPoint |
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344 | * and with a weighted ordering with respect to facetNormal as tiebreaker. |
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345 | * Hence it is sufficient to compute the initial form with respect to facetNormal, |
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346 | * to obtain an initial form with respect to interiorPoint+e*facetNormal, |
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347 | * for e>0 sufficiently small */ |
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348 | std::pair<ideal,ring> flipped = flip(polynomialIdeal,polynomialRing,interiorPoint,facetNormal,*currentStrategy); |
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349 | assume(checkPolynomialInput(flipped.first,flipped.second)); |
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350 | groebnerCone flippedCone(flipped.first, flipped.second, interiorPoint, facetNormal, *currentStrategy); |
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351 | return flippedCone; |
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352 | } |
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353 | |
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354 | |
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355 | /*** |
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356 | * Computes a relative interior point and an outer normal vector for each facet of zc |
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357 | **/ |
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358 | static std::pair<gfan::ZMatrix,gfan::ZMatrix> interiorPointsAndNormalsOfFacets(const gfan::ZCone zc) |
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359 | { |
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360 | gfan::ZMatrix inequalities = zc.getFacets(); |
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361 | gfan::ZMatrix equations = zc.getImpliedEquations(); |
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362 | int r = inequalities.getHeight(); |
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363 | int c = inequalities.getWidth(); |
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364 | |
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365 | /* our cone has r facets, if r==0 return empty matrices */ |
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366 | gfan::ZMatrix relativeInteriorPoints = gfan::ZMatrix(0,c); |
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367 | gfan::ZMatrix outerFacetNormals = gfan::ZMatrix(0,c); |
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368 | if (r==0) |
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369 | return std::make_pair(relativeInteriorPoints,outerFacetNormals); |
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370 | |
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371 | /* next we iterate over each of the r facets, |
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372 | * build the respective cone and add it to the list |
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373 | * this is the i=0 case */ |
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374 | gfan::ZMatrix newInequalities = inequalities.submatrix(1,0,r,c); |
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375 | gfan::ZMatrix newEquations = equations; |
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376 | newEquations.appendRow(inequalities[0]); |
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377 | gfan::ZCone facet = gfan::ZCone(newInequalities,newEquations); |
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378 | relativeInteriorPoints.appendRow(facet.getRelativeInteriorPoint()); |
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379 | assume(zc.contains(relativeInteriorPoints[0]) && !zc.containsRelatively(relativeInteriorPoints[0])); |
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380 | outerFacetNormals.appendRow(-inequalities[0]); |
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381 | |
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382 | /* these are the cases i=1,...,r-2 */ |
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383 | for (int i=1; i<r-1; i++) |
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384 | { |
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385 | newInequalities = inequalities.submatrix(0,0,i,c); |
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386 | newInequalities.append(inequalities.submatrix(i+1,0,r,c)); |
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387 | newEquations = equations; |
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388 | newEquations.appendRow(inequalities[i]); |
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389 | facet = gfan::ZCone(newInequalities,newEquations); |
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390 | relativeInteriorPoints.appendRow(facet.getRelativeInteriorPoint()); |
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391 | assume(zc.contains(relativeInteriorPoints[i]) && !zc.containsRelatively(relativeInteriorPoints[i])); |
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392 | outerFacetNormals.appendRow(-inequalities[i]); |
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393 | } |
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394 | |
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395 | /* this is the i=r-1 case */ |
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396 | newInequalities = inequalities.submatrix(0,0,r-1,c); |
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397 | newEquations = equations; |
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398 | newEquations.appendRow(inequalities[r-1]); |
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399 | facet = gfan::ZCone(newInequalities,newEquations); |
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400 | relativeInteriorPoints.appendRow(facet.getRelativeInteriorPoint()); |
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401 | assume(zc.contains(relativeInteriorPoints[r-1]) && !zc.containsRelatively(relativeInteriorPoints[r-1])); |
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402 | outerFacetNormals.appendRow(-inequalities[r-1]); |
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403 | |
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404 | return std::make_pair(relativeInteriorPoints,outerFacetNormals); |
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405 | } |
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406 | |
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407 | |
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408 | /*** |
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409 | * Returns a complete list of neighboring Groebner cones. |
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410 | **/ |
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411 | groebnerCones groebnerCone::groebnerNeighbours() const |
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412 | { |
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413 | std::pair<gfan::ZMatrix, gfan::ZMatrix> facetsData = interiorPointsAndNormalsOfFacets(polyhedralCone); |
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414 | gfan::ZMatrix interiorPoints = facetsData.first; |
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415 | gfan::ZMatrix facetNormals = facetsData.second; |
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416 | |
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417 | groebnerCones neighbours; |
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418 | for (int i=0; i<interiorPoints.getHeight(); i++) |
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419 | neighbours.insert(this->flipCone(interiorPoints[i],facetNormals[i])); |
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420 | |
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421 | return neighbours; |
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422 | } |
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423 | |
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424 | |
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425 | /*** |
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426 | * Computes a relative interior point for each facet of zc |
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427 | **/ |
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428 | static gfan::ZMatrix interiorPointsOfFacets(const gfan::ZCone zc) |
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429 | { |
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430 | gfan::ZMatrix inequalities = zc.getFacets(); |
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431 | gfan::ZMatrix equations = zc.getImpliedEquations(); |
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432 | int r = inequalities.getHeight(); |
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433 | int c = inequalities.getWidth(); |
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434 | |
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435 | /* our cone has r facets, if r==0 return empty matrices */ |
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436 | gfan::ZMatrix relativeInteriorPoints = gfan::ZMatrix(0,c); |
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437 | if (r==0) return relativeInteriorPoints; |
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438 | |
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439 | /* next we iterate over each of the r facets, |
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440 | * build the respective cone and add it to the list |
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441 | * this is the i=0 case */ |
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442 | gfan::ZMatrix newInequalities = inequalities.submatrix(1,0,r,c); |
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443 | gfan::ZMatrix newEquations = equations; |
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444 | newEquations.appendRow(inequalities[0]); |
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445 | gfan::ZCone facet = gfan::ZCone(newInequalities,newEquations); |
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446 | relativeInteriorPoints.appendRow(facet.getRelativeInteriorPoint()); |
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447 | |
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448 | /* these are the cases i=1,...,r-2 */ |
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449 | for (int i=1; i<r-1; i++) |
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450 | { |
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451 | newInequalities = inequalities.submatrix(0,0,i-1,c); |
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452 | newInequalities.append(inequalities.submatrix(i+1,0,r,c)); |
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453 | newEquations = equations; |
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454 | newEquations.appendRow(inequalities[i]); |
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455 | facet = gfan::ZCone(newInequalities,newEquations); |
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456 | relativeInteriorPoints.appendRow(facet.getRelativeInteriorPoint()); |
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457 | } |
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458 | |
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459 | /* this is the i=r-1 case */ |
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460 | newInequalities = inequalities.submatrix(0,0,r-1,c); |
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461 | newEquations = equations; |
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462 | newEquations.appendRow(inequalities[r-1]); |
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463 | facet = gfan::ZCone(newInequalities,newEquations); |
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464 | relativeInteriorPoints.appendRow(facet.getRelativeInteriorPoint()); |
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465 | |
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466 | return relativeInteriorPoints; |
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467 | } |
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468 | |
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469 | |
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470 | /*** |
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471 | * Returns a complete list of neighboring Groebner cones in the tropical variety. |
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472 | **/ |
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473 | groebnerCones groebnerCone::tropicalNeighbours() const |
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474 | { |
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475 | gfan::ZMatrix interiorPoints = interiorPointsOfFacets(polyhedralCone); |
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476 | groebnerCones neighbours; |
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477 | for (int i=0; i<interiorPoints.getHeight(); i++) |
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478 | { |
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479 | ideal initialIdeal = initial(polynomialIdeal,polynomialRing,interiorPoints[i]); |
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480 | std::set<gfan::ZVector> rays = raysOfTropicalStar(initialIdeal,polynomialRing,interiorPoints[i],*currentStrategy); |
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481 | for (std::set<gfan::ZVector>::iterator ray = rays.begin(); ray!=rays.end(); ray++) |
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482 | neighbours.insert(this->flipCone(interiorPoints[i],*ray)); |
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483 | } |
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484 | return neighbours; |
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485 | } |
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486 | |
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487 | |
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488 | gfan::ZFan* toFanStar(groebnerCones setOfCones) |
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489 | { |
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490 | if (setOfCones.size() > 0) |
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491 | { |
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492 | groebnerCones::iterator sigma = setOfCones.begin(); |
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493 | gfan::ZFan* zf = new gfan::ZFan(sigma->getPolyhedralCone().ambientDimension()); |
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494 | for (; sigma!=setOfCones.end(); sigma++) |
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495 | zf->insert(sigma->getPolyhedralCone()); |
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496 | return zf; |
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497 | } |
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498 | else |
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499 | return new gfan::ZFan(gfan::ZFan::fullFan(currRing->N)); |
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500 | } |
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