## [57ebea]: SimpleMatrix.c Maximize Restore History

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287``` ```/* autopano-sift, Automatic panorama image creation * Copyright (C) 2004 -- Sebastian Nowozin * * This program is free software released under the GNU General Public * License, which is included in this software package (doc/LICENSE). */ /* SimpleMatrix.cs * * Minimal two-dimensional matrix class implementation. * * (C) Copyright 2004 -- Sebastian Nowozin (nowozin@cs.tu-berlin.de) */ #include "AutoPanoSift.h" SimpleMatrix* SimpleMatrix_new0 () { SimpleMatrix* self = (SimpleMatrix*)malloc(sizeof(SimpleMatrix)); self->values = NULL; return self; } void SimpleMatrix_delete(SimpleMatrix* self) { if (self) { DoubleMap_delete(self->values); self->values = NULL; free(self); } } void SimpleMatrix_init (SimpleMatrix* self, int yDim, int xDim) { self->xDim = xDim; self->yDim = yDim; self->values = DoubleMap_new(yDim, xDim); } SimpleMatrix* SimpleMatrix_new (int yDim, int xDim) { SimpleMatrix* self = SimpleMatrix_new0(); self->xDim = xDim; self->yDim = yDim; self->values = DoubleMap_new(yDim, xDim); return self; } SimpleMatrix* SimpleMatrix_clone (SimpleMatrix* self) { SimpleMatrix* cp = SimpleMatrix_new (self->yDim, self->xDim); int x, y; for ( y = 0 ; y < self->yDim ; ++y) { for ( x = 0 ; x < self->xDim ; ++x) { cp->values[y][x] = self->values[y][x]; } } return (cp); } double SimpleMatrix_GetValue(SimpleMatrix* self, int y, int x) { return (self->values[y][x]); } void SimpleMatrix_SetValue(SimpleMatrix* self, int y, int x, double value ) { self->values[y][x] = value; } SimpleMatrix* SimpleMatrix_Mul(SimpleMatrix* m1, SimpleMatrix* m2) { if (m1->xDim != m2->yDim) FatalError ("Matrixes cannot be multiplied, dimension mismatch"); // vanilla! SimpleMatrix* res = SimpleMatrix_new (m1->yDim, m2->xDim); int y; for ( y = 0 ; y < m1->yDim ; ++y) { int x; for ( x = 0 ; x < m2->xDim ; ++x) { int k; for ( k = 0 ; k < m2->yDim ; ++k) res->values[y][x] += m1->values[y][k] * m2->values[k][x]; } } return (res); } double SimpleMatrix_Dot (SimpleMatrix* self, SimpleMatrix* m) { if (self->yDim != m->yDim || self->xDim != 1 || m->xDim != 1) FatalError ("Dotproduct only possible for two equal n x 1 matrices"); double sum = 0.0; int y; for ( y = 0 ; y < self->yDim ; ++y) sum += self->values[y][0] * m->values[y][0]; return (sum); } void SimpleMatrix_Negate (SimpleMatrix* self) { int y; for (y = 0 ; y < self->yDim ; ++y) { int x; for ( x = 0 ; x < self->xDim ; ++x) { self->values[y][x] = -self->values[y][x]; } } } void SimpleMatrix_Inverse (SimpleMatrix* self) { if (self->xDim != self->yDim) FatalError("Matrix x dimension != y dimension"); // Shipley-Coleman inversion, from // http://www.geocities.com/SiliconValley/Lab/4223/fault/ach03.html int dim = self->xDim; int i,j,k; for ( k = 0 ; k < dim ; ++k) { self->values[k][k] = - 1.0 / self->values[k][k]; for ( i = 0 ; i < dim ; ++i) { if (i != k) self->values[i][k] *= self->values[k][k]; } for ( i = 0 ; i < dim ; ++i) { if (i != k) { for ( j = 0 ; j < dim ; ++j) { if (j != k) self->values[i][j] += self->values[i][k] * self->values[k][j]; } } } for ( i = 0 ; i < dim ; ++i) { if (i != k) self->values[k][i] *= self->values[k][k]; } } for ( i = 0 ; i < dim ; ++i) { for ( j = 0 ; j < dim ; ++j) self->values[i][j] = -self->values[i][j]; } } // The vector 'vec' is used both for input/output purposes. As input, it // contains the vector v, and after this method finishes it contains x, // the solution in the formula // self * x = v // This matrix might get row-swapped, too. void SimpleMatrix_SolveLinear (SimpleMatrix* self, SimpleMatrix* vec) { if (self->xDim != self->yDim || self->yDim != vec->yDim) FatalError ("Matrix not quadratic or vector dimension mismatch"); // Gaussian Elimination Algorithm, as described by // "Numerical Methods - A Software Approach", R.L. Johnston // Forward elimination with partial pivoting int x, y; for (y = 0 ; y < (self->yDim - 1) ; ++y) { // Searching for the largest pivot (to get "multipliers < 1.0 to // minimize round-off errors") int yMaxIndex = y; double yMaxValue = abs (self->values[y][y]); int py; for (py = y ; py < self->yDim ; ++py) { if (abs (self->values[py][y]) > yMaxValue) { yMaxValue = abs (self->values[py][y]); yMaxIndex = py; } } // if a larger row has been found, swap with the current one SimpleMatrix_SwapRow (self, y, yMaxIndex); SimpleMatrix_SwapRow (vec, y, yMaxIndex); // Now do the elimination left of the diagonal for ( py = y + 1 ; py < self->yDim ; ++py) { // always <= 1.0 double elimMul = self->values[py][y] / self->values[y][y]; for ( x = 0 ; x < self->xDim ; ++x) self->values[py][x] -= elimMul * self->values[y][x]; // FIXME: do we really need this? vec->values[py][0] -= elimMul * vec->values[y][0]; } } // Back substitution for ( y = self->yDim - 1 ; y >= 0 ; --y) { double solY = vec->values[y][0]; for ( x = self->xDim - 1 ; x > y ; --x) solY -= self->values[y][x] * vec->values[x][0]; vec->values[y][0] = solY / self->values[y][y]; } } // Swap two rows r1, r2 void SimpleMatrix_SwapRow (SimpleMatrix* self, int r1, int r2) { if (r1 == r2) return; int x; for ( x = 0 ; x < self->xDim ; ++x) { double temp = self->values[r1][x]; self->values[r1][x] = self->values[r2][x]; self->values[r2][x] = temp; } } char* SimpleMatrix_ToString (SimpleMatrix* self) { int len = 5 + self->yDim * (3 + self->xDim*15); char* str = (char*)malloc(len); char* p = str; p += sprintf(p, "( "); int x,y; for ( y = 0 ; y < self->yDim ; ++y) { if (y > 0) p += sprintf(p, "\n "); for ( x = 0 ; x < self->xDim ; ++x) { if (x > 0) p += sprintf(p, " "); p += sprintf(p, "%3.015g", self->values[y][x]); } } p+= sprintf(p, " )"); if (p > str + len) { FatalError("SimpleMatrix_toString overflow: len=%d, strlen=%d\n", len, p-str); } return str; } #ifdef TEST_MAIN int main(int argc, char* argv[]) { SimpleMatrix * A = SimpleMatrix_new(3,3); A->values[0][0] = 1; A->values[0][1] = 2; A->values[0][2] = 3; A->values[1][0] = 4; A->values[1][1] = 5; A->values[1][2] = 6; A->values[2][0] = 7; A->values[2][1] = 9; A->values[2][2] = 8; WriteLine("A=%s", SimpleMatrix_ToString(A)); SimpleMatrix * B = SimpleMatrix_new(3,1); B->values[0][0] = 1; B->values[1][0] = 2; B->values[2][0] = 3; WriteLine("B=%s", SimpleMatrix_ToString(B)); SimpleMatrix * C = SimpleMatrix_Mul(A,B); WriteLine("A*B=%s", SimpleMatrix_ToString(C)); SimpleMatrix_delete(A); SimpleMatrix_delete(B); SimpleMatrix_delete(C); return 0; } #endif ```