1 | /**************************************** |
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2 | * Computer Algebra System SINGULAR * |
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3 | ****************************************/ |
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4 | /* $Id: binom.cc,v 1.3 1997-04-02 15:06:55 Singular Exp $ */ |
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5 | |
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6 | /* |
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7 | * ABSTRACT - set order (=number of monomial) for dp |
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8 | */ |
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9 | |
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10 | /* includes */ |
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11 | #include <limits.h> |
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12 | #include "mod2.h" |
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13 | #include "tok.h" |
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14 | #include "mmemory.h" |
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15 | #include "febase.h" |
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16 | #include "polys.h" |
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17 | #include "binom.h" |
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18 | |
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19 | #ifdef TEST_MAC_ORDER |
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20 | static char rcsid[] = "$Id: binom.cc,v 1.3 1997-04-02 15:06:55 Singular Exp $"; |
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21 | |
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22 | extern int pComponentOrder; |
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23 | /* ----------- global variables, set by bBinomSet --------------------- */ |
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24 | static int *bBinomials=NULL; |
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25 | static int bSize; |
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26 | int bHighdeg; |
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27 | static int bHighdeg_1; |
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28 | |
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29 | /*0 implementation*/ |
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30 | static inline int bBinom(int i,int j) |
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31 | { |
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32 | return bBinomials[(j-1)*(bHighdeg_1)+i-j+1/*j-1,i-j*/]; |
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33 | } |
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34 | |
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35 | void bSetm(poly p) |
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36 | { |
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37 | int i = pTotaldegree(p); |
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38 | |
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39 | if (i<=bHighdeg) |
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40 | { |
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41 | i=1; |
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42 | p->Order = -INT_MAX; |
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43 | //int expsum=0; |
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44 | //while (i<=pVariables) |
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45 | //{ |
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46 | // expsum += pGetExp(p,i); |
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47 | // p->Order += bBinom(expsum,i); |
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48 | // expsum++; |
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49 | // i++; |
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50 | //} |
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51 | |
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52 | int *ip=bBinomials+pGetExp(p,1); |
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53 | loop |
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54 | { |
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55 | p->Order += (*ip); |
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56 | if (i==pVariables) break; |
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57 | i++; |
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58 | ip+=bHighdeg_1+pGetExp(p,i); |
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59 | } |
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60 | } |
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61 | else |
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62 | p->Order=i; |
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63 | } |
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64 | |
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65 | static int bComp1dpc(poly p1, poly p2) |
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66 | { |
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67 | int o1=p1->Order, o2=p2->Order; |
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68 | if (o1 > o2) return 1; |
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69 | if (o1 < o2) return -1; |
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70 | |
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71 | /* now o1==o2: */ |
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72 | if (o1>0) |
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73 | { |
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74 | int i = pVariables; |
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75 | while ((i>1) && (p1->exp[i]==p2->exp[i])) |
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76 | i--; |
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77 | if (i>1) |
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78 | { |
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79 | if (p1->exp[i] < p2->exp[i]) return 1; |
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80 | return -1; |
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81 | } |
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82 | } |
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83 | o1=p1->exp[0]; |
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84 | o2=p2->exp[0]; |
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85 | if (o1==o2/*p1->exp[0]==p2->exp[0]*/) return 0; |
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86 | if (o1>o2) return -pComponentOrder; |
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87 | return pComponentOrder; |
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88 | } |
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89 | |
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90 | /*2 |
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91 | * compute the length of a polynomial (in l) |
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92 | * and the degree of the monomial with maximal degree: the first one |
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93 | * this works for the polynomial case with degree orderings |
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94 | * (both c,dp and dp,c) |
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95 | */ |
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96 | static int bLDegb(poly p,int *l) |
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97 | { |
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98 | short k=p->exp[0]; |
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99 | int o = pFDeg(p); |
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100 | int ll=1; |
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101 | |
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102 | while (((p=pNext(p))!=NULL) && (pGetComp(p)==k)) |
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103 | { |
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104 | ll++; |
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105 | } |
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106 | *l=ll; |
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107 | return o; |
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108 | } |
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109 | |
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110 | /*2 |
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111 | * compute the length of a polynomial (in l) |
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112 | * and the degree of the monomial with maximal degree: the last one |
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113 | */ |
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114 | static int bLDeg0(poly p,int *l) |
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115 | { |
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116 | short k=p->exp[0]; |
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117 | int ll=1; |
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118 | |
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119 | while ((pNext(p)!=NULL) && (pGetComp(pNext(p))==k)) |
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120 | { |
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121 | pIter(p); |
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122 | ll++; |
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123 | } |
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124 | *l=ll; |
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125 | return (pFDeg(p)); |
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126 | } |
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127 | |
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128 | /* |
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129 | * (i,j) in bBinomials[j-1,i-j+1] |
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130 | * table size is: pVariables * (bHighdeg+1) |
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131 | * bHighdeg_1==bHighdeg+1 |
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132 | */ |
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133 | void bBinomSet() |
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134 | { |
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135 | bHighdeg=1; |
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136 | long long t=1; |
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137 | long long h_n=1+pVariables; |
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138 | while ((bHighdeg<512) |
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139 | && ((t=(((long long)t*(long long)h_n)/(long long)bHighdeg))<INT_MAX)) |
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140 | { |
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141 | bHighdeg++; |
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142 | h_n++; |
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143 | } |
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144 | bHighdeg_1=bHighdeg; |
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145 | bHighdeg--; |
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146 | |
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147 | if(bBinomials!=NULL) Free((ADDRESS)bBinomials,bSize); |
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148 | bSize = pVariables*(bHighdeg+1)*sizeof(int); |
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149 | bBinomials = (int*)Alloc(bSize); |
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150 | |
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151 | Print("max deg=%d, table size=%d bytes\n",bHighdeg,bSize); |
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152 | |
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153 | for(int j=1;j<=bHighdeg;j++) |
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154 | { |
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155 | bBinomials[j/*0,j*/] = j; |
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156 | for (int i=1;i<pVariables;i++) |
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157 | { |
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158 | bBinomials[i*(bHighdeg_1)+j/*i,j*/] |
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159 | = bBinomials[(i-1)*(bHighdeg_1)+j/*i-1,j*/]*(j+i)/(i+1); |
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160 | } |
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161 | } |
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162 | for (int i=0;i<pVariables;i++) |
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163 | { |
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164 | bBinomials[i*(bHighdeg_1)/*i,0*/]=0; |
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165 | } |
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166 | pSetm =bSetm; |
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167 | pComp0=bComp1dpc; |
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168 | pFDeg =pTotaldegree; |
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169 | pLDeg =bLDegb; /* if pOrdSgn==1 */ |
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170 | } |
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171 | #endif |
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