1 | /**************************************** |
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2 | * Computer Algebra System SINGULAR * |
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3 | ****************************************/ |
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4 | /* $Id: modulop.cc,v 1.26 2001-08-27 14:47:12 Singular Exp $ */ |
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5 | /* |
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6 | * ABSTRACT: numbers modulo p (<=32003) |
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7 | */ |
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8 | |
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9 | #include <string.h> |
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10 | #include "mod2.h" |
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11 | #include <mylimits.h> |
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12 | #include "tok.h" |
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13 | #include "febase.h" |
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14 | #include "omalloc.h" |
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15 | #include "numbers.h" |
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16 | #include "longrat.h" |
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17 | #include "mpr_complex.h" |
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18 | #include "ring.h" |
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19 | #include "modulop.h" |
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20 | |
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21 | int npPrimeM=0; |
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22 | int npGen=0; |
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23 | int npPminus1M=0; |
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24 | int npMapPrime; |
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25 | |
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26 | CARDINAL *npExpTable=NULL; |
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27 | CARDINAL *npLogTable=NULL; |
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28 | |
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29 | |
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30 | BOOLEAN npGreaterZero (number k) |
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31 | { |
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32 | int h = (int) k; |
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33 | return ((int)h !=0) && (h <= (npPrimeM>>1)); |
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34 | } |
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35 | |
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36 | unsigned long npMultMod(unsigned long a, unsigned long b) |
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37 | { |
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38 | unsigned long c = a*b; |
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39 | c = c % npPrimeM; |
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40 | assume(c == (unsigned long) npMultM((number) a, (number) b)); |
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41 | return c; |
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42 | } |
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43 | |
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44 | number npMult (number a,number b) |
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45 | { |
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46 | if (((int)a == 0) || ((int)b == 0)) |
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47 | return (number)0; |
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48 | else |
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49 | { |
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50 | return npMultM(a,b); |
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51 | } |
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52 | } |
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53 | |
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54 | /*2 |
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55 | * create a number from int |
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56 | */ |
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57 | number npInit (int i) |
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58 | { |
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59 | while (i < 0) i += npPrimeM; |
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60 | while ((i>1) && (i >= npPrimeM)) i -= npPrimeM; |
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61 | return (number)i; |
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62 | } |
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63 | |
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64 | /*2 |
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65 | * convert a number to int (-p/2 .. p/2) |
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66 | */ |
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67 | int npInt(number &n) |
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68 | { |
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69 | if ((int)n > (npPrimeM >>1)) return ((int)n -npPrimeM); |
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70 | else return (int)n; |
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71 | } |
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72 | |
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73 | number npAdd (number a, number b) |
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74 | { |
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75 | return npAddM(a,b); |
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76 | } |
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77 | |
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78 | number npSub (number a, number b) |
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79 | { |
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80 | return npSubM(a,b); |
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81 | } |
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82 | |
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83 | BOOLEAN npIsZero (number a) |
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84 | { |
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85 | return 0 == (int)a; |
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86 | } |
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87 | |
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88 | BOOLEAN npIsOne (number a) |
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89 | { |
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90 | return 1 == (int)a; |
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91 | } |
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92 | |
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93 | BOOLEAN npIsMOne (number a) |
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94 | { |
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95 | return ((npPminus1M == (int)a)&&(1!=(int)a)); |
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96 | } |
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97 | |
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98 | number npDiv (number a,number b) |
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99 | { |
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100 | if ((int)a==0) |
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101 | return (number)0; |
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102 | else if ((int)b==0) |
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103 | { |
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104 | WerrorS("div by 0"); |
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105 | return (number)0; |
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106 | } |
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107 | else |
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108 | { |
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109 | int s = npLogTable[(int)a] - npLogTable[(int)b]; |
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110 | if (s < 0) |
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111 | s += npPminus1M; |
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112 | return (number)npExpTable[s]; |
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113 | } |
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114 | } |
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115 | |
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116 | number npInvers (number c) |
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117 | { |
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118 | if ((int)c==0) |
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119 | { |
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120 | WerrorS("1/0"); |
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121 | return (number)0; |
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122 | } |
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123 | return (number)npExpTable[npPminus1M - npLogTable[(int)c]]; |
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124 | } |
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125 | |
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126 | number npNeg (number c) |
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127 | { |
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128 | if ((int)c==0) return c; |
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129 | return npNegM(c); |
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130 | } |
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131 | |
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132 | BOOLEAN npGreater (number a,number b) |
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133 | { |
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134 | return (int)a != (int)b; |
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135 | } |
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136 | |
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137 | BOOLEAN npEqual (number a,number b) |
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138 | { |
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139 | // return (int)a == (int)b; |
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140 | return npEqualM(a,b); |
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141 | } |
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142 | |
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143 | void npWrite (number &a) |
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144 | { |
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145 | if ((int)a > (npPrimeM >>1)) StringAppend("-%d",npPrimeM-((int)a)); |
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146 | else StringAppend("%d",(int)a); |
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147 | } |
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148 | |
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149 | void npPower (number a, int i, number * result) |
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150 | { |
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151 | if (i==0) |
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152 | { |
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153 | //npInit(1,result); |
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154 | *(int *)result = 1; |
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155 | } |
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156 | else if (i==1) |
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157 | { |
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158 | *result = a; |
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159 | } |
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160 | else |
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161 | { |
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162 | npPower(a,i-1,result); |
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163 | *result = npMultM(a,*result); |
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164 | } |
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165 | } |
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166 | |
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167 | char* npEati(char *s, int *i) |
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168 | { |
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169 | |
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170 | if (((*s) >= '0') && ((*s) <= '9')) |
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171 | { |
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172 | (*i) = 0; |
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173 | do |
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174 | { |
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175 | (*i) *= 10; |
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176 | (*i) += *s++ - '0'; |
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177 | if ((*i) >= (MAX_INT_VAL / 10)) (*i) = (*i) % npPrimeM; |
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178 | } |
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179 | while (((*s) >= '0') && ((*s) <= '9')); |
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180 | if ((*i) >= npPrimeM) (*i) = (*i) % npPrimeM; |
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181 | } |
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182 | else (*i) = 1; |
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183 | return s; |
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184 | } |
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185 | |
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186 | char * npRead (char *s, number *a) |
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187 | { |
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188 | int z; |
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189 | int n=1; |
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190 | |
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191 | s = npEati(s, &z); |
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192 | if ((*s) == '/') |
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193 | { |
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194 | s++; |
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195 | s = npEati(s, &n); |
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196 | } |
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197 | *a = npDiv((number)z,(number)n); |
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198 | return s; |
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199 | } |
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200 | |
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201 | /*2 |
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202 | * the last used charcteristic |
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203 | */ |
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204 | //int npGetChar() |
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205 | //{ |
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206 | // return npPrimeM; |
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207 | //} |
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208 | |
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209 | /*2 |
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210 | * set the charcteristic (allocate and init tables) |
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211 | */ |
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212 | |
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213 | void npSetChar(int c, ring r) |
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214 | { |
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215 | // int i, w; |
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216 | |
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217 | // if (c==npPrimeM) return; |
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218 | // if (npPrimeM > 1) |
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219 | // { |
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220 | // omFreeSize( (ADDRESS)npExpTable,npPrimeM*sizeof(CARDINAL) ); |
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221 | // omFreeSize( (ADDRESS)npLogTable,npPrimeM*sizeof(CARDINAL) ); |
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222 | // } |
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223 | if ((c>1) || (c<(-1))) |
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224 | { |
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225 | if (c>1) npPrimeM = c; |
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226 | else npPrimeM = -c; |
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227 | npPminus1M = npPrimeM - 1; |
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228 | // npExpTable= (CARDINAL *)omAlloc( npPrimeM*sizeof(CARDINAL) ); |
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229 | // npLogTable= (CARDINAL *)omAlloc( npPrimeM*sizeof(CARDINAL) ); |
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230 | // omMarkAsStaticAddr(npExpTable); |
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231 | // omMarkAsStaticAddr(npLogTable); |
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232 | // memcpy(npExpTable,r->cf->npExpTable,npPrimeM*sizeof(CARDINAL)); |
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233 | // memcpy(npLogTable,r->cf->npLogTable,npPrimeM*sizeof(CARDINAL)); |
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234 | npExpTable=r->cf->npExpTable; |
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235 | npLogTable=r->cf->npLogTable; |
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236 | npGen = npExpTable[1]; |
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237 | } |
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238 | else |
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239 | { |
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240 | npPrimeM=0; |
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241 | npExpTable=NULL; |
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242 | npLogTable=NULL; |
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243 | } |
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244 | } |
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245 | |
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246 | void npInitChar(int c, ring r) |
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247 | { |
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248 | int i, w; |
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249 | |
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250 | if ((c>1) || (c<(-1))) |
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251 | { |
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252 | if (c>1) r->cf->npPrimeM = c; |
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253 | else r->cf->npPrimeM = -c; |
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254 | r->cf->npPminus1M = r->cf->npPrimeM - 1; |
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255 | r->cf->npExpTable= (CARDINAL *)omAlloc( r->cf->npPrimeM*sizeof(CARDINAL) ); |
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256 | r->cf->npLogTable= (CARDINAL *)omAlloc( r->cf->npPrimeM*sizeof(CARDINAL) ); |
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257 | r->cf->npExpTable[0] = 1; |
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258 | r->cf->npLogTable[0] = 0; |
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259 | if (r->cf->npPrimeM > 2) |
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260 | { |
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261 | w = 1; |
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262 | loop |
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263 | { |
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264 | r->cf->npLogTable[1] = 0; |
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265 | w++; |
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266 | i = 0; |
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267 | loop |
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268 | { |
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269 | i++; |
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270 | r->cf->npExpTable[i] = (int)(((long)w * (long)r->cf->npExpTable[i-1]) |
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271 | % r->cf->npPrimeM); |
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272 | r->cf->npLogTable[r->cf->npExpTable[i]] = i; |
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273 | if (/*(i == npPrimeM - 1 ) ||*/ (r->cf->npExpTable[i] == 1)) |
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274 | break; |
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275 | } |
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276 | if (i == r->cf->npPrimeM - 1) |
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277 | break; |
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278 | } |
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279 | } |
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280 | else |
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281 | { |
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282 | r->cf->npExpTable[1] = 1; |
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283 | r->cf->npLogTable[1] = 0; |
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284 | } |
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285 | } |
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286 | else |
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287 | { |
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288 | WarnS("nInitChar failed"); |
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289 | } |
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290 | } |
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291 | |
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292 | #ifdef LDEBUG |
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293 | BOOLEAN npDBTest (number a, char *f, int l) |
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294 | { |
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295 | if (((int)a<0) || ((int)a>npPrimeM)) |
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296 | { |
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297 | return FALSE; |
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298 | } |
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299 | return TRUE; |
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300 | } |
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301 | #endif |
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302 | |
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303 | number npMap0(number from) |
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304 | { |
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305 | return npInit(nlModP(from,npPrimeM)); |
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306 | } |
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307 | |
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308 | number npMapP(number from) |
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309 | { |
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310 | int i = (int)from; |
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311 | if (i>npMapPrime/2) |
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312 | { |
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313 | i-=npMapPrime; |
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314 | while (i < 0) i+=npPrimeM; |
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315 | } |
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316 | i%=npPrimeM; |
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317 | return (number)i; |
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318 | } |
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319 | |
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320 | static number npMapLongR(number from) |
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321 | { |
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322 | gmp_float *ff=(gmp_float*)from; |
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323 | mpf_t *f=ff->_mpfp(); |
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324 | number res; |
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325 | lint *dest,*ndest; |
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326 | int size,i; |
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327 | int e,al,bl,iz,in; |
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328 | mp_ptr qp,dd,nn; |
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329 | |
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330 | size = (*f)[0]._mp_size; |
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331 | if (size == 0) |
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332 | return npInit(0); |
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333 | if(size<0) |
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334 | size = -size; |
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335 | |
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336 | qp = (*f)[0]._mp_d; |
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337 | while(qp[0]==0) |
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338 | { |
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339 | qp++; |
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340 | size--; |
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341 | } |
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342 | |
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343 | if(npPrimeM>2) |
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344 | e=(*f)[0]._mp_exp-size; |
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345 | else |
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346 | e=0; |
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347 | res = (number)omAllocBin(rnumber_bin); |
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348 | #if defined(LDEBUG) |
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349 | res->debug=123456; |
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350 | #endif |
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351 | dest = &(res->z); |
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352 | |
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353 | if (e<0) |
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354 | { |
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355 | al = dest->_mp_size = size; |
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356 | if (al<2) al = 2; |
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357 | dd = (mp_ptr)omAlloc(sizeof(mp_limb_t)*al); |
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358 | for (i=0;i<size;i++) dd[i] = qp[i]; |
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359 | bl = 1-e; |
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360 | nn = (mp_ptr)omAlloc(sizeof(mp_limb_t)*bl); |
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361 | nn[bl-1] = 1; |
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362 | for (i=bl-2;i>=0;i--) nn[i] = 0; |
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363 | ndest = &(res->n); |
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364 | ndest->_mp_d = nn; |
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365 | ndest->_mp_alloc = ndest->_mp_size = bl; |
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366 | res->s = 0; |
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367 | in=mpz_mmod_ui(NULL,ndest,npPrimeM); |
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368 | mpz_clear(ndest); |
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369 | } |
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370 | else |
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371 | { |
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372 | al = dest->_mp_size = size+e; |
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373 | if (al<2) al = 2; |
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374 | dd = (mp_ptr)omAlloc(sizeof(mp_limb_t)*al); |
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375 | for (i=0;i<size;i++) dd[i+e] = qp[i]; |
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376 | for (i=0;i<e;i++) dd[i] = 0; |
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377 | res->s = 3; |
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378 | } |
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379 | |
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380 | dest->_mp_d = dd; |
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381 | dest->_mp_alloc = al; |
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382 | iz=mpz_mmod_ui(NULL,dest,npPrimeM); |
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383 | mpz_clear(dest); |
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384 | omFreeBin((ADDRESS)res, rnumber_bin); |
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385 | if(res->s==0) |
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386 | iz=(int)npDiv((number)iz,(number)in); |
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387 | return (number)iz; |
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388 | } |
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389 | |
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390 | nMapFunc npSetMap(ring src, ring dst) |
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391 | { |
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392 | if (rField_is_Q(src)) |
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393 | { |
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394 | return npMap0; |
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395 | } |
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396 | if ( rField_is_Zp(src) ) |
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397 | { |
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398 | if (rChar(src) == rChar(dst)) |
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399 | { |
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400 | return ndCopy; |
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401 | } |
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402 | else |
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403 | { |
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404 | npMapPrime=rChar(src); |
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405 | return npMapP; |
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406 | } |
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407 | } |
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408 | if (rField_is_long_R(src)) |
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409 | { |
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410 | return npMapLongR; |
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411 | } |
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412 | return NULL; /* default */ |
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413 | } |
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