[493c477] | 1 | /* emacs edit mode for this file is -*- C++ -*- */ |
---|
[2dd068] | 2 | |
---|
| 3 | #ifndef INCL_GFOPS_H |
---|
| 4 | #define INCL_GFOPS_H |
---|
| 5 | |
---|
[e4fe2b] | 6 | // #include "config.h" |
---|
[25c3c2b] | 7 | |
---|
[bb20e7] | 8 | #ifndef NOSTREAMIO |
---|
[1dc616] | 9 | #ifdef HAVE_IOSTREAM |
---|
| 10 | #include <iostream> |
---|
[181148] | 11 | #define OSTREAM std::ostream |
---|
[1dc616] | 12 | #elif defined(HAVE_IOSTREAM_H) |
---|
[2dd068] | 13 | #include <iostream.h> |
---|
[181148] | 14 | #define OSTREAM ostream |
---|
[1dc616] | 15 | #endif |
---|
[bb20e7] | 16 | #endif /* NOSTREAMIO */ |
---|
[2dd068] | 17 | |
---|
[650f2d8] | 18 | #include "cf_assert.h" |
---|
[bb20e7] | 19 | |
---|
[2dd068] | 20 | #include "cf_defs.h" |
---|
[25c3c2b] | 21 | #include "canonicalform.h" |
---|
[2dd068] | 22 | |
---|
| 23 | extern int gf_q; |
---|
| 24 | extern int gf_p; |
---|
| 25 | extern int gf_n; |
---|
| 26 | extern int gf_q1; |
---|
| 27 | extern int gf_m1; |
---|
| 28 | extern char gf_name; |
---|
| 29 | |
---|
| 30 | extern unsigned short * gf_table; |
---|
| 31 | |
---|
[25c3c2b] | 32 | extern CanonicalForm gf_mipo; |
---|
[2dd068] | 33 | |
---|
[2adb1c] | 34 | //{{{ predicates |
---|
| 35 | inline bool gf_iszero ( int a ) |
---|
| 36 | { |
---|
| 37 | return gf_q == a; |
---|
| 38 | } |
---|
| 39 | |
---|
[8710ff0] | 40 | inline bool gf_iszero ( long a ) |
---|
| 41 | { |
---|
| 42 | return gf_q == a; |
---|
| 43 | } |
---|
| 44 | |
---|
[2adb1c] | 45 | inline bool gf_isone ( int a ) |
---|
| 46 | { |
---|
| 47 | return 0 == a; |
---|
| 48 | } |
---|
[8710ff0] | 49 | |
---|
| 50 | inline bool gf_isone ( long a ) |
---|
| 51 | { |
---|
| 52 | return 0 == a; |
---|
| 53 | } |
---|
[2adb1c] | 54 | //}}} |
---|
| 55 | |
---|
| 56 | //{{{ conversion functions |
---|
[2dd068] | 57 | inline int gf_int2gf ( int i ) |
---|
| 58 | { |
---|
| 59 | while ( i < 0 ) |
---|
| 60 | i += gf_p; |
---|
| 61 | while ( i >= gf_p ) |
---|
| 62 | i -= gf_p; |
---|
| 63 | if ( i == 0 ) |
---|
| 64 | return gf_q; |
---|
| 65 | int c = 0; |
---|
| 66 | while ( i > 1 ) { |
---|
| 67 | c = gf_table[c]; |
---|
| 68 | i--; |
---|
| 69 | } |
---|
| 70 | return c; |
---|
| 71 | } |
---|
[8710ff0] | 72 | |
---|
| 73 | inline long gf_int2gf ( long i ) |
---|
| 74 | { |
---|
| 75 | while ( i < 0 ) |
---|
| 76 | i += gf_p; |
---|
| 77 | while ( i >= gf_p ) |
---|
| 78 | i -= gf_p; |
---|
| 79 | if ( i == 0 ) |
---|
| 80 | return gf_q; |
---|
| 81 | long c = 0; |
---|
| 82 | while ( i > 1 ) { |
---|
| 83 | c = gf_table[c]; |
---|
| 84 | i--; |
---|
| 85 | } |
---|
| 86 | return c; |
---|
| 87 | } |
---|
[2adb1c] | 88 | //}}} |
---|
[2dd068] | 89 | |
---|
[2adb1c] | 90 | //{{{ zero and one |
---|
[2dd068] | 91 | inline int gf_zero() |
---|
| 92 | { |
---|
| 93 | return gf_q; |
---|
| 94 | } |
---|
| 95 | |
---|
| 96 | inline int gf_one() |
---|
| 97 | { |
---|
| 98 | return 0; |
---|
| 99 | } |
---|
[2adb1c] | 100 | //}}} |
---|
[2dd068] | 101 | |
---|
[987a48] | 102 | //{{{ inline int gf_sign ( int a ) |
---|
[2adb1c] | 103 | // docu: see imm_sign() |
---|
[987a48] | 104 | inline |
---|
| 105 | int gf_sign ( int a ) |
---|
[2dd068] | 106 | { |
---|
| 107 | if ( gf_iszero( a ) ) |
---|
| 108 | return 0; |
---|
| 109 | else |
---|
| 110 | return 1; |
---|
| 111 | } |
---|
[987a48] | 112 | //}}} |
---|
[2dd068] | 113 | |
---|
[2adb1c] | 114 | //{{{ arithmetic operators |
---|
[2dd068] | 115 | inline int gf_neg ( int a ) |
---|
| 116 | { |
---|
| 117 | // -z^a=z^a*(-1)=z^a*gf_m1; |
---|
| 118 | if ( a == gf_q ) return a; |
---|
| 119 | int i = a + gf_m1; |
---|
| 120 | if ( i >= gf_q1 ) |
---|
| 121 | i -= gf_q1; |
---|
| 122 | return i; |
---|
| 123 | } |
---|
| 124 | |
---|
| 125 | inline int gf_add ( int a, int b ) |
---|
| 126 | { |
---|
| 127 | // z^a+z^b=z^b*(z^(a-b)+1), if a>=b; |
---|
| 128 | // =z^a*(z^(b-a)+1), if a<b; |
---|
| 129 | if ( a == gf_q ) return b; |
---|
| 130 | if ( b == gf_q ) return a; |
---|
| 131 | int zb, zab, r; |
---|
| 132 | if ( a >= b ) { |
---|
| 133 | zb = b; |
---|
| 134 | zab = a - b; |
---|
| 135 | } |
---|
| 136 | else { |
---|
| 137 | zb = a; |
---|
| 138 | zab = b - a; |
---|
| 139 | } |
---|
| 140 | if ( gf_table[zab] == gf_q ) |
---|
| 141 | r = gf_q; /*if z^(a-b)+1 =0*/ |
---|
| 142 | else { |
---|
| 143 | r= zb + gf_table[zab]; |
---|
| 144 | if ( r >= gf_q1 ) |
---|
| 145 | r -= gf_q1; |
---|
| 146 | } |
---|
| 147 | return r; |
---|
| 148 | } |
---|
| 149 | |
---|
| 150 | inline int gf_sub ( int a, int b ) |
---|
| 151 | { |
---|
| 152 | return gf_add( a, gf_neg( b ) ); |
---|
| 153 | } |
---|
| 154 | |
---|
| 155 | inline int gf_mul ( int a, int b ) |
---|
| 156 | { |
---|
| 157 | if ( a == gf_q || b == gf_q ) |
---|
| 158 | return gf_q; |
---|
| 159 | else { |
---|
| 160 | int i = a + b; |
---|
| 161 | if ( i >= gf_q1 ) i -= gf_q1; |
---|
| 162 | return i; |
---|
| 163 | } |
---|
| 164 | } |
---|
| 165 | |
---|
[8710ff0] | 166 | inline long gf_mul ( long a, int b ) |
---|
| 167 | { |
---|
| 168 | if ( a == gf_q || b == gf_q ) |
---|
| 169 | return gf_q; |
---|
| 170 | else { |
---|
| 171 | long i = a + b; |
---|
| 172 | if ( i >= gf_q1 ) i -= gf_q1; |
---|
| 173 | return i; |
---|
| 174 | } |
---|
| 175 | } |
---|
| 176 | |
---|
[2dd068] | 177 | inline int gf_div ( int a, int b ) |
---|
| 178 | { |
---|
| 179 | ASSERT( b != gf_q, "divide by zero" ); |
---|
| 180 | if ( a == gf_q ) |
---|
| 181 | return gf_q; |
---|
| 182 | else { |
---|
| 183 | int s = a - b; |
---|
| 184 | if (s < 0) |
---|
| 185 | s += gf_q1; |
---|
| 186 | return s; |
---|
| 187 | } |
---|
| 188 | } |
---|
| 189 | |
---|
| 190 | inline int gf_inv ( int a ) |
---|
| 191 | { |
---|
| 192 | ASSERT( a != gf_q, "divide by zero" ); |
---|
| 193 | return gf_q1 - a; |
---|
| 194 | } |
---|
[2adb1c] | 195 | //}}} |
---|
[2dd068] | 196 | |
---|
[2adb1c] | 197 | //{{{ input/output |
---|
[bb20e7] | 198 | #ifndef NOSTREAMIO |
---|
[181148] | 199 | inline void gf_print ( OSTREAM & os, int a ) |
---|
[2dd068] | 200 | { |
---|
| 201 | if ( a == gf_q ) |
---|
| 202 | os << "0"; |
---|
| 203 | else if ( a == 0 ) |
---|
| 204 | os << "1"; |
---|
| 205 | else if ( a == 1 ) |
---|
| 206 | os << gf_name; |
---|
| 207 | else |
---|
| 208 | os << gf_name << "^" << a; |
---|
| 209 | } |
---|
[bb20e7] | 210 | #endif /* NOSTREAMIO */ |
---|
[2adb1c] | 211 | //}}} |
---|
[2dd068] | 212 | |
---|
[2adb1c] | 213 | //{{{ exponentation |
---|
[2dd068] | 214 | inline int gf_power ( int a, int n ) |
---|
| 215 | { |
---|
| 216 | if ( n == 0 ) |
---|
| 217 | return 0; |
---|
| 218 | else if ( n == 1 ) |
---|
| 219 | return a; |
---|
| 220 | else |
---|
| 221 | return gf_mul( a, gf_power( a, n-1 ) ); |
---|
| 222 | } |
---|
[8710ff0] | 223 | |
---|
| 224 | inline long gf_power ( long a, int n ) |
---|
| 225 | { |
---|
| 226 | if ( n == 0 ) |
---|
| 227 | return 0; |
---|
| 228 | else if ( n == 1 ) |
---|
| 229 | return a; |
---|
| 230 | else |
---|
| 231 | return gf_mul( a, gf_power( a, n-1 ) ); |
---|
| 232 | } |
---|
[2adb1c] | 233 | //}}} |
---|
[2dd068] | 234 | |
---|
| 235 | void gf_setcharacteristic ( int p, int n, char name ); |
---|
| 236 | |
---|
[25c3c2b] | 237 | // Singular needs this |
---|
| 238 | /*BEGINPUBLIC*/ |
---|
| 239 | |
---|
[8710ff0] | 240 | long gf_gf2ff ( long a ); |
---|
[2dd068] | 241 | int gf_gf2ff ( int a ); |
---|
| 242 | |
---|
[8710ff0] | 243 | bool gf_isff ( long a ); |
---|
[2dd068] | 244 | bool gf_isff ( int a ); |
---|
| 245 | |
---|
[25c3c2b] | 246 | /*ENDPUBLIC*/ |
---|
| 247 | |
---|
[493c477] | 248 | #endif /* ! INCL_GFOPS_H */ |
---|