| 1 | gezelter | 1490 | #include <stdio.h> | 
| 2 |  |  | #include <math.h> | 
| 3 |  |  | #include <stdlib.h> | 
| 4 |  |  | #include "MatVec3.h" | 
| 5 |  |  |  | 
| 6 |  |  | /* | 
| 7 |  |  | * Contains various utilities for dealing with 3x3 matrices and | 
| 8 |  |  | * length 3 vectors | 
| 9 |  |  | */ | 
| 10 |  |  |  | 
| 11 |  |  | void identityMat3(double A[3][3]) { | 
| 12 |  |  | int i; | 
| 13 |  |  | for (i = 0; i < 3; i++) { | 
| 14 |  |  | A[i][0] = A[i][1] = A[i][2] = 0.0; | 
| 15 |  |  | A[i][i] = 1.0; | 
| 16 |  |  | } | 
| 17 |  |  | } | 
| 18 |  |  |  | 
| 19 |  |  | void swapVectors3(double v1[3], double v2[3]) { | 
| 20 |  |  | int i; | 
| 21 |  |  | for (i = 0; i < 3; i++) { | 
| 22 |  |  | double tmp = v1[i]; | 
| 23 |  |  | v1[i] = v2[i]; | 
| 24 |  |  | v2[i] = tmp; | 
| 25 |  |  | } | 
| 26 |  |  | } | 
| 27 |  |  |  | 
| 28 |  |  | double normalize3(double x[3]) { | 
| 29 |  |  | double den; | 
| 30 |  |  | int i; | 
| 31 |  |  | if ( (den = norm3(x)) != 0.0 ) { | 
| 32 |  |  | for (i=0; i < 3; i++) | 
| 33 |  |  | { | 
| 34 |  |  | x[i] /= den; | 
| 35 |  |  | } | 
| 36 |  |  | } | 
| 37 |  |  | return den; | 
| 38 |  |  | } | 
| 39 |  |  |  | 
| 40 |  |  | void matMul3(double a[3][3], double b[3][3], double c[3][3]) { | 
| 41 |  |  | double r00, r01, r02, r10, r11, r12, r20, r21, r22; | 
| 42 |  |  |  | 
| 43 |  |  | r00 = a[0][0]*b[0][0] + a[0][1]*b[1][0] + a[0][2]*b[2][0]; | 
| 44 |  |  | r01 = a[0][0]*b[0][1] + a[0][1]*b[1][1] + a[0][2]*b[2][1]; | 
| 45 |  |  | r02 = a[0][0]*b[0][2] + a[0][1]*b[1][2] + a[0][2]*b[2][2]; | 
| 46 |  |  |  | 
| 47 |  |  | r10 = a[1][0]*b[0][0] + a[1][1]*b[1][0] + a[1][2]*b[2][0]; | 
| 48 |  |  | r11 = a[1][0]*b[0][1] + a[1][1]*b[1][1] + a[1][2]*b[2][1]; | 
| 49 |  |  | r12 = a[1][0]*b[0][2] + a[1][1]*b[1][2] + a[1][2]*b[2][2]; | 
| 50 |  |  |  | 
| 51 |  |  | r20 = a[2][0]*b[0][0] + a[2][1]*b[1][0] + a[2][2]*b[2][0]; | 
| 52 |  |  | r21 = a[2][0]*b[0][1] + a[2][1]*b[1][1] + a[2][2]*b[2][1]; | 
| 53 |  |  | r22 = a[2][0]*b[0][2] + a[2][1]*b[1][2] + a[2][2]*b[2][2]; | 
| 54 |  |  |  | 
| 55 |  |  | c[0][0] = r00; c[0][1] = r01; c[0][2] = r02; | 
| 56 |  |  | c[1][0] = r10; c[1][1] = r11; c[1][2] = r12; | 
| 57 |  |  | c[2][0] = r20; c[2][1] = r21; c[2][2] = r22; | 
| 58 |  |  | } | 
| 59 |  |  |  | 
| 60 |  |  | void matVecMul3(double m[3][3], double inVec[3], double outVec[3]) { | 
| 61 |  |  | double a0, a1, a2; | 
| 62 |  |  |  | 
| 63 |  |  | a0 = inVec[0];  a1 = inVec[1];  a2 = inVec[2]; | 
| 64 |  |  |  | 
| 65 |  |  | outVec[0] = m[0][0]*a0 + m[0][1]*a1 + m[0][2]*a2; | 
| 66 |  |  | outVec[1] = m[1][0]*a0 + m[1][1]*a1 + m[1][2]*a2; | 
| 67 |  |  | outVec[2] = m[2][0]*a0 + m[2][1]*a1 + m[2][2]*a2; | 
| 68 |  |  | } | 
| 69 |  |  |  | 
| 70 |  |  | double matDet3(double a[3][3]) { | 
| 71 |  |  | int i, j, k; | 
| 72 |  |  | double determinant; | 
| 73 |  |  |  | 
| 74 |  |  | determinant = 0.0; | 
| 75 |  |  |  | 
| 76 |  |  | for(i = 0; i < 3; i++) { | 
| 77 |  |  | j = (i+1)%3; | 
| 78 |  |  | k = (i+2)%3; | 
| 79 |  |  |  | 
| 80 |  |  | determinant += a[0][i] * (a[1][j]*a[2][k] - a[1][k]*a[2][j]); | 
| 81 |  |  | } | 
| 82 |  |  |  | 
| 83 |  |  | return determinant; | 
| 84 |  |  | } | 
| 85 |  |  |  | 
| 86 |  |  | void invertMat3(double a[3][3], double b[3][3]) { | 
| 87 |  |  |  | 
| 88 |  |  | int  i, j, k, l, m, n; | 
| 89 |  |  | double determinant; | 
| 90 |  |  |  | 
| 91 |  |  | determinant = matDet3( a ); | 
| 92 |  |  |  | 
| 93 |  |  | if (determinant == 0.0) { | 
| 94 |  |  | sprintf( painCave.errMsg, | 
| 95 |  |  | "Can't invert a matrix with a zero determinant!\n"); | 
| 96 |  |  | painCave.isFatal = 1; | 
| 97 |  |  | simError(); | 
| 98 |  |  | } | 
| 99 |  |  |  | 
| 100 |  |  | for (i=0; i < 3; i++) { | 
| 101 |  |  | j = (i+1)%3; | 
| 102 |  |  | k = (i+2)%3; | 
| 103 |  |  | for(l = 0; l < 3; l++) { | 
| 104 |  |  | m = (l+1)%3; | 
| 105 |  |  | n = (l+2)%3; | 
| 106 |  |  |  | 
| 107 |  |  | b[l][i] = (a[j][m]*a[k][n] - a[j][n]*a[k][m]) / determinant; | 
| 108 |  |  | } | 
| 109 |  |  | } | 
| 110 |  |  | } | 
| 111 |  |  |  | 
| 112 |  |  | void transposeMat3(double in[3][3], double out[3][3]) { | 
| 113 |  |  | double temp[3][3]; | 
| 114 |  |  | int i, j; | 
| 115 |  |  |  | 
| 116 |  |  | for (i = 0; i < 3; i++) { | 
| 117 |  |  | for (j = 0; j < 3; j++) { | 
| 118 |  |  | temp[j][i] = in[i][j]; | 
| 119 |  |  | } | 
| 120 |  |  | } | 
| 121 |  |  | for (i = 0; i < 3; i++) { | 
| 122 |  |  | for (j = 0; j < 3; j++) { | 
| 123 |  |  | out[i][j] = temp[i][j]; | 
| 124 |  |  | } | 
| 125 |  |  | } | 
| 126 |  |  | } | 
| 127 |  |  |  | 
| 128 |  |  | void printMat3(double A[3][3] ){ | 
| 129 |  |  |  | 
| 130 |  |  | fprintf(stderr, "[ %g, %g, %g ]\n[ %g, %g, %g ]\n[ %g, %g, %g ]\n", | 
| 131 |  |  | A[0][0] , A[0][1] , A[0][2], | 
| 132 |  |  | A[1][0] , A[1][1] , A[1][2], | 
| 133 |  |  | A[2][0] , A[2][1] , A[2][2]) ; | 
| 134 |  |  | } | 
| 135 |  |  |  | 
| 136 |  |  | void printMat9(double A[9] ){ | 
| 137 |  |  |  | 
| 138 |  |  | fprintf(stderr, "[ %g, %g, %g ]\n[ %g, %g, %g ]\n[ %g, %g, %g ]\n", | 
| 139 |  |  | A[0], A[1], A[2], | 
| 140 |  |  | A[3], A[4], A[5], | 
| 141 |  |  | A[6], A[7], A[8]); | 
| 142 |  |  | } | 
| 143 |  |  |  | 
| 144 |  |  | double matTrace3(double m[3][3]){ | 
| 145 |  |  | double trace; | 
| 146 |  |  | trace = m[0][0] + m[1][1] + m[2][2]; | 
| 147 |  |  |  | 
| 148 |  |  | return trace; | 
| 149 |  |  | } | 
| 150 |  |  |  | 
| 151 |  |  | void crossProduct3(double a[3],double b[3], double out[3]){ | 
| 152 |  |  |  | 
| 153 |  |  | out[0] = a[1] * b[2] - a[2] * b[1]; | 
| 154 |  |  | out[1] = a[2] * b[0] - a[0] * b[2] ; | 
| 155 |  |  | out[2] = a[0] * b[1] - a[1] * b[0]; | 
| 156 |  |  |  | 
| 157 |  |  | } | 
| 158 |  |  |  | 
| 159 |  |  | double dotProduct3(double a[3], double b[3]){ | 
| 160 |  |  | return a[0]*b[0] + a[1]*b[1]+ a[2]*b[2]; | 
| 161 |  |  | } | 
| 162 |  |  |  | 
| 163 |  |  | //---------------------------------------------------------------------------- | 
| 164 |  |  | // Extract the eigenvalues and eigenvectors from a 3x3 matrix. | 
| 165 |  |  | // The eigenvectors (the columns of V) will be normalized. | 
| 166 |  |  | // The eigenvectors are aligned optimally with the x, y, and z | 
| 167 |  |  | // axes respectively. | 
| 168 |  |  |  | 
| 169 |  |  | void diagonalize3x3(const double A[3][3], double w[3], double V[3][3]) { | 
| 170 |  |  | int i,j,k,maxI; | 
| 171 |  |  | double tmp, maxVal; | 
| 172 |  |  |  | 
| 173 |  |  | // do the matrix[3][3] to **matrix conversion for Jacobi | 
| 174 |  |  | double C[3][3]; | 
| 175 |  |  | double *ATemp[3],*VTemp[3]; | 
| 176 |  |  | for (i = 0; i < 3; i++) | 
| 177 |  |  | { | 
| 178 |  |  | C[i][0] = A[i][0]; | 
| 179 |  |  | C[i][1] = A[i][1]; | 
| 180 |  |  | C[i][2] = A[i][2]; | 
| 181 |  |  | ATemp[i] = C[i]; | 
| 182 |  |  | VTemp[i] = V[i]; | 
| 183 |  |  | } | 
| 184 |  |  |  | 
| 185 |  |  | // diagonalize using Jacobi | 
| 186 |  |  | JacobiN(ATemp,3,w,VTemp); | 
| 187 |  |  |  | 
| 188 |  |  | // if all the eigenvalues are the same, return identity matrix | 
| 189 |  |  | if (w[0] == w[1] && w[0] == w[2]) | 
| 190 |  |  | { | 
| 191 |  |  | identityMat3(V); | 
| 192 |  |  | return; | 
| 193 |  |  | } | 
| 194 |  |  |  | 
| 195 |  |  | // transpose temporarily, it makes it easier to sort the eigenvectors | 
| 196 |  |  | transposeMat3(V,V); | 
| 197 |  |  |  | 
| 198 |  |  | // if two eigenvalues are the same, re-orthogonalize to optimally line | 
| 199 |  |  | // up the eigenvectors with the x, y, and z axes | 
| 200 |  |  | for (i = 0; i < 3; i++) | 
| 201 |  |  | { | 
| 202 |  |  | if (w[(i+1)%3] == w[(i+2)%3]) // two eigenvalues are the same | 
| 203 |  |  | { | 
| 204 |  |  | // find maximum element of the independant eigenvector | 
| 205 |  |  | maxVal = fabs(V[i][0]); | 
| 206 |  |  | maxI = 0; | 
| 207 |  |  | for (j = 1; j < 3; j++) | 
| 208 |  |  | { | 
| 209 |  |  | if (maxVal < (tmp = fabs(V[i][j]))) | 
| 210 |  |  | { | 
| 211 |  |  | maxVal = tmp; | 
| 212 |  |  | maxI = j; | 
| 213 |  |  | } | 
| 214 |  |  | } | 
| 215 |  |  | // swap the eigenvector into its proper position | 
| 216 |  |  | if (maxI != i) | 
| 217 |  |  | { | 
| 218 |  |  | tmp = w[maxI]; | 
| 219 |  |  | w[maxI] = w[i]; | 
| 220 |  |  | w[i] = tmp; | 
| 221 |  |  | swapVectors3(V[i],V[maxI]); | 
| 222 |  |  | } | 
| 223 |  |  | // maximum element of eigenvector should be positive | 
| 224 |  |  | if (V[maxI][maxI] < 0) | 
| 225 |  |  | { | 
| 226 |  |  | V[maxI][0] = -V[maxI][0]; | 
| 227 |  |  | V[maxI][1] = -V[maxI][1]; | 
| 228 |  |  | V[maxI][2] = -V[maxI][2]; | 
| 229 |  |  | } | 
| 230 |  |  |  | 
| 231 |  |  | // re-orthogonalize the other two eigenvectors | 
| 232 |  |  | j = (maxI+1)%3; | 
| 233 |  |  | k = (maxI+2)%3; | 
| 234 |  |  |  | 
| 235 |  |  | V[j][0] = 0.0; | 
| 236 |  |  | V[j][1] = 0.0; | 
| 237 |  |  | V[j][2] = 0.0; | 
| 238 |  |  | V[j][j] = 1.0; | 
| 239 |  |  | crossProduct3(V[maxI],V[j],V[k]); | 
| 240 |  |  | normalize3(V[k]); | 
| 241 |  |  | crossProduct3(V[k],V[maxI],V[j]); | 
| 242 |  |  |  | 
| 243 |  |  | // transpose vectors back to columns | 
| 244 |  |  | transposeMat3(V,V); | 
| 245 |  |  | return; | 
| 246 |  |  | } | 
| 247 |  |  | } | 
| 248 |  |  |  | 
| 249 |  |  | // the three eigenvalues are different, just sort the eigenvectors | 
| 250 |  |  | // to align them with the x, y, and z axes | 
| 251 |  |  |  | 
| 252 |  |  | // find the vector with the largest x element, make that vector | 
| 253 |  |  | // the first vector | 
| 254 |  |  | maxVal = fabs(V[0][0]); | 
| 255 |  |  | maxI = 0; | 
| 256 |  |  | for (i = 1; i < 3; i++) | 
| 257 |  |  | { | 
| 258 |  |  | if (maxVal < (tmp = fabs(V[i][0]))) | 
| 259 |  |  | { | 
| 260 |  |  | maxVal = tmp; | 
| 261 |  |  | maxI = i; | 
| 262 |  |  | } | 
| 263 |  |  | } | 
| 264 |  |  | // swap eigenvalue and eigenvector | 
| 265 |  |  | if (maxI != 0) | 
| 266 |  |  | { | 
| 267 |  |  | tmp = w[maxI]; | 
| 268 |  |  | w[maxI] = w[0]; | 
| 269 |  |  | w[0] = tmp; | 
| 270 |  |  | swapVectors3(V[maxI],V[0]); | 
| 271 |  |  | } | 
| 272 |  |  | // do the same for the y element | 
| 273 |  |  | if (fabs(V[1][1]) < fabs(V[2][1])) | 
| 274 |  |  | { | 
| 275 |  |  | tmp = w[2]; | 
| 276 |  |  | w[2] = w[1]; | 
| 277 |  |  | w[1] = tmp; | 
| 278 |  |  | swapVectors3(V[2],V[1]); | 
| 279 |  |  | } | 
| 280 |  |  |  | 
| 281 |  |  | // ensure that the sign of the eigenvectors is correct | 
| 282 |  |  | for (i = 0; i < 2; i++) | 
| 283 |  |  | { | 
| 284 |  |  | if (V[i][i] < 0) | 
| 285 |  |  | { | 
| 286 |  |  | V[i][0] = -V[i][0]; | 
| 287 |  |  | V[i][1] = -V[i][1]; | 
| 288 |  |  | V[i][2] = -V[i][2]; | 
| 289 |  |  | } | 
| 290 |  |  | } | 
| 291 |  |  | // set sign of final eigenvector to ensure that determinant is positive | 
| 292 |  |  | if (matDet3(V) < 0) | 
| 293 |  |  | { | 
| 294 |  |  | V[2][0] = -V[2][0]; | 
| 295 |  |  | V[2][1] = -V[2][1]; | 
| 296 |  |  | V[2][2] = -V[2][2]; | 
| 297 |  |  | } | 
| 298 |  |  |  | 
| 299 |  |  | // transpose the eigenvectors back again | 
| 300 |  |  | transposeMat3(V,V); | 
| 301 |  |  | } | 
| 302 |  |  |  | 
| 303 |  |  |  | 
| 304 |  |  | #define MAT_ROTATE(a,i,j,k,l) g=a[i][j];h=a[k][l];a[i][j]=g-s*(h+g*tau); a[k][l]=h+s*(g-h*tau); | 
| 305 |  |  |  | 
| 306 |  |  | #define MAX_ROTATIONS 20 | 
| 307 |  |  |  | 
| 308 |  |  | // Jacobi iteration for the solution of eigenvectors/eigenvalues of a nxn | 
| 309 |  |  | // real symmetric matrix. Square nxn matrix a; size of matrix in n; | 
| 310 |  |  | // output eigenvalues in w; and output eigenvectors in v. Resulting | 
| 311 |  |  | // eigenvalues/vectors are sorted in decreasing order; eigenvectors are | 
| 312 |  |  | // normalized. | 
| 313 |  |  | int JacobiN(double **a, int n, double *w, double **v) { | 
| 314 |  |  |  | 
| 315 |  |  | int i, j, k, iq, ip, numPos; | 
| 316 |  |  | int ceil_half_n; | 
| 317 |  |  | double tresh, theta, tau, t, sm, s, h, g, c, tmp; | 
| 318 |  |  | double bspace[4], zspace[4]; | 
| 319 |  |  | double *b = bspace; | 
| 320 |  |  | double *z = zspace; | 
| 321 |  |  |  | 
| 322 |  |  |  | 
| 323 |  |  | // only allocate memory if the matrix is large | 
| 324 |  |  | if (n > 4) | 
| 325 |  |  | { | 
| 326 |  |  | b = (double *) calloc(n, sizeof(double)); | 
| 327 |  |  | z = (double *) calloc(n, sizeof(double)); | 
| 328 |  |  | } | 
| 329 |  |  |  | 
| 330 |  |  | // initialize | 
| 331 |  |  | for (ip=0; ip<n; ip++) | 
| 332 |  |  | { | 
| 333 |  |  | for (iq=0; iq<n; iq++) | 
| 334 |  |  | { | 
| 335 |  |  | v[ip][iq] = 0.0; | 
| 336 |  |  | } | 
| 337 |  |  | v[ip][ip] = 1.0; | 
| 338 |  |  | } | 
| 339 |  |  | for (ip=0; ip<n; ip++) | 
| 340 |  |  | { | 
| 341 |  |  | b[ip] = w[ip] = a[ip][ip]; | 
| 342 |  |  | z[ip] = 0.0; | 
| 343 |  |  | } | 
| 344 |  |  |  | 
| 345 |  |  | // begin rotation sequence | 
| 346 |  |  | for (i=0; i<MAX_ROTATIONS; i++) | 
| 347 |  |  | { | 
| 348 |  |  | sm = 0.0; | 
| 349 |  |  | for (ip=0; ip<n-1; ip++) | 
| 350 |  |  | { | 
| 351 |  |  | for (iq=ip+1; iq<n; iq++) | 
| 352 |  |  | { | 
| 353 |  |  | sm += fabs(a[ip][iq]); | 
| 354 |  |  | } | 
| 355 |  |  | } | 
| 356 |  |  | if (sm == 0.0) | 
| 357 |  |  | { | 
| 358 |  |  | break; | 
| 359 |  |  | } | 
| 360 |  |  |  | 
| 361 |  |  | if (i < 3)                                // first 3 sweeps | 
| 362 |  |  | { | 
| 363 |  |  | tresh = 0.2*sm/(n*n); | 
| 364 |  |  | } | 
| 365 |  |  | else | 
| 366 |  |  | { | 
| 367 |  |  | tresh = 0.0; | 
| 368 |  |  | } | 
| 369 |  |  |  | 
| 370 |  |  | for (ip=0; ip<n-1; ip++) | 
| 371 |  |  | { | 
| 372 |  |  | for (iq=ip+1; iq<n; iq++) | 
| 373 |  |  | { | 
| 374 |  |  | g = 100.0*fabs(a[ip][iq]); | 
| 375 |  |  |  | 
| 376 |  |  | // after 4 sweeps | 
| 377 |  |  | if (i > 3 && (fabs(w[ip])+g) == fabs(w[ip]) | 
| 378 |  |  | && (fabs(w[iq])+g) == fabs(w[iq])) | 
| 379 |  |  | { | 
| 380 |  |  | a[ip][iq] = 0.0; | 
| 381 |  |  | } | 
| 382 |  |  | else if (fabs(a[ip][iq]) > tresh) | 
| 383 |  |  | { | 
| 384 |  |  | h = w[iq] - w[ip]; | 
| 385 |  |  | if ( (fabs(h)+g) == fabs(h)) | 
| 386 |  |  | { | 
| 387 |  |  | t = (a[ip][iq]) / h; | 
| 388 |  |  | } | 
| 389 |  |  | else | 
| 390 |  |  | { | 
| 391 |  |  | theta = 0.5*h / (a[ip][iq]); | 
| 392 |  |  | t = 1.0 / (fabs(theta)+sqrt(1.0+theta*theta)); | 
| 393 |  |  | if (theta < 0.0) | 
| 394 |  |  | { | 
| 395 |  |  | t = -t; | 
| 396 |  |  | } | 
| 397 |  |  | } | 
| 398 |  |  | c = 1.0 / sqrt(1+t*t); | 
| 399 |  |  | s = t*c; | 
| 400 |  |  | tau = s/(1.0+c); | 
| 401 |  |  | h = t*a[ip][iq]; | 
| 402 |  |  | z[ip] -= h; | 
| 403 |  |  | z[iq] += h; | 
| 404 |  |  | w[ip] -= h; | 
| 405 |  |  | w[iq] += h; | 
| 406 |  |  | a[ip][iq]=0.0; | 
| 407 |  |  |  | 
| 408 |  |  | // ip already shifted left by 1 unit | 
| 409 |  |  | for (j = 0;j <= ip-1;j++) | 
| 410 |  |  | { | 
| 411 |  |  | MAT_ROTATE(a,j,ip,j,iq) | 
| 412 |  |  | } | 
| 413 |  |  | // ip and iq already shifted left by 1 unit | 
| 414 |  |  | for (j = ip+1;j <= iq-1;j++) | 
| 415 |  |  | { | 
| 416 |  |  | MAT_ROTATE(a,ip,j,j,iq) | 
| 417 |  |  | } | 
| 418 |  |  | // iq already shifted left by 1 unit | 
| 419 |  |  | for (j=iq+1; j<n; j++) | 
| 420 |  |  | { | 
| 421 |  |  | MAT_ROTATE(a,ip,j,iq,j) | 
| 422 |  |  | } | 
| 423 |  |  | for (j=0; j<n; j++) | 
| 424 |  |  | { | 
| 425 |  |  | MAT_ROTATE(v,j,ip,j,iq) | 
| 426 |  |  | } | 
| 427 |  |  | } | 
| 428 |  |  | } | 
| 429 |  |  | } | 
| 430 |  |  |  | 
| 431 |  |  | for (ip=0; ip<n; ip++) | 
| 432 |  |  | { | 
| 433 |  |  | b[ip] += z[ip]; | 
| 434 |  |  | w[ip] = b[ip]; | 
| 435 |  |  | z[ip] = 0.0; | 
| 436 |  |  | } | 
| 437 |  |  | } | 
| 438 |  |  |  | 
| 439 |  |  | //// this is NEVER called | 
| 440 |  |  | if ( i >= MAX_ROTATIONS ) | 
| 441 |  |  | { | 
| 442 |  |  | sprintf( painCave.errMsg, | 
| 443 |  |  | "Jacobi: Error extracting eigenfunctions!\n"); | 
| 444 |  |  | painCave.isFatal = 1; | 
| 445 |  |  | simError(); | 
| 446 |  |  | return 0; | 
| 447 |  |  | } | 
| 448 |  |  |  | 
| 449 |  |  | // sort eigenfunctions                 these changes do not affect accuracy | 
| 450 |  |  | for (j=0; j<n-1; j++)                  // boundary incorrect | 
| 451 |  |  | { | 
| 452 |  |  | k = j; | 
| 453 |  |  | tmp = w[k]; | 
| 454 |  |  | for (i=j+1; i<n; i++)             // boundary incorrect, shifted already | 
| 455 |  |  | { | 
| 456 |  |  | if (w[i] >= tmp)                   // why exchage if same? | 
| 457 |  |  | { | 
| 458 |  |  | k = i; | 
| 459 |  |  | tmp = w[k]; | 
| 460 |  |  | } | 
| 461 |  |  | } | 
| 462 |  |  | if (k != j) | 
| 463 |  |  | { | 
| 464 |  |  | w[k] = w[j]; | 
| 465 |  |  | w[j] = tmp; | 
| 466 |  |  | for (i=0; i<n; i++) | 
| 467 |  |  | { | 
| 468 |  |  | tmp = v[i][j]; | 
| 469 |  |  | v[i][j] = v[i][k]; | 
| 470 |  |  | v[i][k] = tmp; | 
| 471 |  |  | } | 
| 472 |  |  | } | 
| 473 |  |  | } | 
| 474 |  |  | // insure eigenvector consistency (i.e., Jacobi can compute vectors that | 
| 475 |  |  | // are negative of one another (.707,.707,0) and (-.707,-.707,0). This can | 
| 476 |  |  | // reek havoc in hyperstreamline/other stuff. We will select the most | 
| 477 |  |  | // positive eigenvector. | 
| 478 |  |  | ceil_half_n = (n >> 1) + (n & 1); | 
| 479 |  |  | for (j=0; j<n; j++) | 
| 480 |  |  | { | 
| 481 |  |  | for (numPos=0, i=0; i<n; i++) | 
| 482 |  |  | { | 
| 483 |  |  | if ( v[i][j] >= 0.0 ) | 
| 484 |  |  | { | 
| 485 |  |  | numPos++; | 
| 486 |  |  | } | 
| 487 |  |  | } | 
| 488 |  |  | //    if ( numPos < ceil(double(n)/double(2.0)) ) | 
| 489 |  |  | if ( numPos < ceil_half_n) | 
| 490 |  |  | { | 
| 491 |  |  | for(i=0; i<n; i++) | 
| 492 |  |  | { | 
| 493 |  |  | v[i][j] *= -1.0; | 
| 494 |  |  | } | 
| 495 |  |  | } | 
| 496 |  |  | } | 
| 497 |  |  |  | 
| 498 |  |  | if (n > 4) | 
| 499 |  |  | { | 
| 500 |  |  | free(b); | 
| 501 |  |  | free(z); | 
| 502 |  |  | } | 
| 503 |  |  | return 1; | 
| 504 |  |  | } | 
| 505 |  |  |  | 
| 506 |  |  | #undef MAT_ROTATE | 
| 507 |  |  | #undef MAX_ROTATIONS |