| 1 | /* | 
| 2 | * Copyright (c) 2005 The University of Notre Dame. All Rights Reserved. | 
| 3 | * | 
| 4 | * The University of Notre Dame grants you ("Licensee") a | 
| 5 | * non-exclusive, royalty free, license to use, modify and | 
| 6 | * redistribute this software in source and binary code form, provided | 
| 7 | * that the following conditions are met: | 
| 8 | * | 
| 9 | * 1. Acknowledgement of the program authors must be made in any | 
| 10 | *    publication of scientific results based in part on use of the | 
| 11 | *    program.  An acceptable form of acknowledgement is citation of | 
| 12 | *    the article in which the program was described (Matthew | 
| 13 | *    A. Meineke, Charles F. Vardeman II, Teng Lin, Christopher | 
| 14 | *    J. Fennell and J. Daniel Gezelter, "OOPSE: An Object-Oriented | 
| 15 | *    Parallel Simulation Engine for Molecular Dynamics," | 
| 16 | *    J. Comput. Chem. 26, pp. 252-271 (2005)) | 
| 17 | * | 
| 18 | * 2. Redistributions of source code must retain the above copyright | 
| 19 | *    notice, this list of conditions and the following disclaimer. | 
| 20 | * | 
| 21 | * 3. Redistributions in binary form must reproduce the above copyright | 
| 22 | *    notice, this list of conditions and the following disclaimer in the | 
| 23 | *    documentation and/or other materials provided with the | 
| 24 | *    distribution. | 
| 25 | * | 
| 26 | * This software is provided "AS IS," without a warranty of any | 
| 27 | * kind. All express or implied conditions, representations and | 
| 28 | * warranties, including any implied warranty of merchantability, | 
| 29 | * fitness for a particular purpose or non-infringement, are hereby | 
| 30 | * excluded.  The University of Notre Dame and its licensors shall not | 
| 31 | * be liable for any damages suffered by licensee as a result of | 
| 32 | * using, modifying or distributing the software or its | 
| 33 | * derivatives. In no event will the University of Notre Dame or its | 
| 34 | * licensors be liable for any lost revenue, profit or data, or for | 
| 35 | * direct, indirect, special, consequential, incidental or punitive | 
| 36 | * damages, however caused and regardless of the theory of liability, | 
| 37 | * arising out of the use of or inability to use software, even if the | 
| 38 | * University of Notre Dame has been advised of the possibility of | 
| 39 | * such damages. | 
| 40 | */ | 
| 41 |  | 
| 42 | #include <stdio.h> | 
| 43 | #include <math.h> | 
| 44 | #include <stdlib.h> | 
| 45 | #include "math/MatVec3.h" | 
| 46 |  | 
| 47 | /* | 
| 48 | * Contains various utilities for dealing with 3x3 matrices and | 
| 49 | * length 3 vectors | 
| 50 | */ | 
| 51 |  | 
| 52 | void identityMat3(RealType A[3][3]) { | 
| 53 | int i; | 
| 54 | for (i = 0; i < 3; i++) { | 
| 55 | A[i][0] = A[i][1] = A[i][2] = 0.0; | 
| 56 | A[i][i] = 1.0; | 
| 57 | } | 
| 58 | } | 
| 59 |  | 
| 60 | void swapVectors3(RealType v1[3], RealType v2[3]) { | 
| 61 | int i; | 
| 62 | for (i = 0; i < 3; i++) { | 
| 63 | RealType tmp = v1[i]; | 
| 64 | v1[i] = v2[i]; | 
| 65 | v2[i] = tmp; | 
| 66 | } | 
| 67 | } | 
| 68 |  | 
| 69 | RealType normalize3(RealType x[3]) { | 
| 70 | RealType den; | 
| 71 | int i; | 
| 72 | if ( (den = norm3(x)) != 0.0 ) { | 
| 73 | for (i=0; i < 3; i++) | 
| 74 | { | 
| 75 | x[i] /= den; | 
| 76 | } | 
| 77 | } | 
| 78 | return den; | 
| 79 | } | 
| 80 |  | 
| 81 | void matMul3(RealType a[3][3], RealType b[3][3], RealType c[3][3]) { | 
| 82 | RealType r00, r01, r02, r10, r11, r12, r20, r21, r22; | 
| 83 |  | 
| 84 | r00 = a[0][0]*b[0][0] + a[0][1]*b[1][0] + a[0][2]*b[2][0]; | 
| 85 | r01 = a[0][0]*b[0][1] + a[0][1]*b[1][1] + a[0][2]*b[2][1]; | 
| 86 | r02 = a[0][0]*b[0][2] + a[0][1]*b[1][2] + a[0][2]*b[2][2]; | 
| 87 |  | 
| 88 | r10 = a[1][0]*b[0][0] + a[1][1]*b[1][0] + a[1][2]*b[2][0]; | 
| 89 | r11 = a[1][0]*b[0][1] + a[1][1]*b[1][1] + a[1][2]*b[2][1]; | 
| 90 | r12 = a[1][0]*b[0][2] + a[1][1]*b[1][2] + a[1][2]*b[2][2]; | 
| 91 |  | 
| 92 | r20 = a[2][0]*b[0][0] + a[2][1]*b[1][0] + a[2][2]*b[2][0]; | 
| 93 | r21 = a[2][0]*b[0][1] + a[2][1]*b[1][1] + a[2][2]*b[2][1]; | 
| 94 | r22 = a[2][0]*b[0][2] + a[2][1]*b[1][2] + a[2][2]*b[2][2]; | 
| 95 |  | 
| 96 | c[0][0] = r00; c[0][1] = r01; c[0][2] = r02; | 
| 97 | c[1][0] = r10; c[1][1] = r11; c[1][2] = r12; | 
| 98 | c[2][0] = r20; c[2][1] = r21; c[2][2] = r22; | 
| 99 | } | 
| 100 |  | 
| 101 | void matVecMul3(RealType m[3][3], RealType inVec[3], RealType outVec[3]) { | 
| 102 | RealType a0, a1, a2; | 
| 103 |  | 
| 104 | a0 = inVec[0];  a1 = inVec[1];  a2 = inVec[2]; | 
| 105 |  | 
| 106 | outVec[0] = m[0][0]*a0 + m[0][1]*a1 + m[0][2]*a2; | 
| 107 | outVec[1] = m[1][0]*a0 + m[1][1]*a1 + m[1][2]*a2; | 
| 108 | outVec[2] = m[2][0]*a0 + m[2][1]*a1 + m[2][2]*a2; | 
| 109 | } | 
| 110 |  | 
| 111 | RealType matDet3(RealType a[3][3]) { | 
| 112 | int i, j, k; | 
| 113 | RealType determinant; | 
| 114 |  | 
| 115 | determinant = 0.0; | 
| 116 |  | 
| 117 | for(i = 0; i < 3; i++) { | 
| 118 | j = (i+1)%3; | 
| 119 | k = (i+2)%3; | 
| 120 |  | 
| 121 | determinant += a[0][i] * (a[1][j]*a[2][k] - a[1][k]*a[2][j]); | 
| 122 | } | 
| 123 |  | 
| 124 | return determinant; | 
| 125 | } | 
| 126 |  | 
| 127 | void invertMat3(RealType a[3][3], RealType b[3][3]) { | 
| 128 |  | 
| 129 | int  i, j, k, l, m, n; | 
| 130 | RealType determinant; | 
| 131 |  | 
| 132 | determinant = matDet3( a ); | 
| 133 |  | 
| 134 | if (determinant == 0.0) { | 
| 135 | sprintf( painCave.errMsg, | 
| 136 | "Can't invert a matrix with a zero determinant!\n"); | 
| 137 | painCave.isFatal = 1; | 
| 138 | simError(); | 
| 139 | } | 
| 140 |  | 
| 141 | for (i=0; i < 3; i++) { | 
| 142 | j = (i+1)%3; | 
| 143 | k = (i+2)%3; | 
| 144 | for(l = 0; l < 3; l++) { | 
| 145 | m = (l+1)%3; | 
| 146 | n = (l+2)%3; | 
| 147 |  | 
| 148 | b[l][i] = (a[j][m]*a[k][n] - a[j][n]*a[k][m]) / determinant; | 
| 149 | } | 
| 150 | } | 
| 151 | } | 
| 152 |  | 
| 153 | void transposeMat3(RealType in[3][3], RealType out[3][3]) { | 
| 154 | RealType temp[3][3]; | 
| 155 | int i, j; | 
| 156 |  | 
| 157 | for (i = 0; i < 3; i++) { | 
| 158 | for (j = 0; j < 3; j++) { | 
| 159 | temp[j][i] = in[i][j]; | 
| 160 | } | 
| 161 | } | 
| 162 | for (i = 0; i < 3; i++) { | 
| 163 | for (j = 0; j < 3; j++) { | 
| 164 | out[i][j] = temp[i][j]; | 
| 165 | } | 
| 166 | } | 
| 167 | } | 
| 168 |  | 
| 169 | void printMat3(RealType A[3][3] ){ | 
| 170 |  | 
| 171 | fprintf(stderr, "[ %g, %g, %g ]\n[ %g, %g, %g ]\n[ %g, %g, %g ]\n", | 
| 172 | A[0][0] , A[0][1] , A[0][2], | 
| 173 | A[1][0] , A[1][1] , A[1][2], | 
| 174 | A[2][0] , A[2][1] , A[2][2]) ; | 
| 175 | } | 
| 176 |  | 
| 177 | void printMat9(RealType A[9] ){ | 
| 178 |  | 
| 179 | fprintf(stderr, "[ %g, %g, %g ]\n[ %g, %g, %g ]\n[ %g, %g, %g ]\n", | 
| 180 | A[0], A[1], A[2], | 
| 181 | A[3], A[4], A[5], | 
| 182 | A[6], A[7], A[8]); | 
| 183 | } | 
| 184 |  | 
| 185 | RealType matTrace3(RealType m[3][3]){ | 
| 186 | RealType trace; | 
| 187 | trace = m[0][0] + m[1][1] + m[2][2]; | 
| 188 |  | 
| 189 | return trace; | 
| 190 | } | 
| 191 |  | 
| 192 | void crossProduct3(RealType a[3],RealType b[3], RealType out[3]){ | 
| 193 |  | 
| 194 | out[0] = a[1] * b[2] - a[2] * b[1]; | 
| 195 | out[1] = a[2] * b[0] - a[0] * b[2] ; | 
| 196 | out[2] = a[0] * b[1] - a[1] * b[0]; | 
| 197 |  | 
| 198 | } | 
| 199 |  | 
| 200 | RealType dotProduct3(RealType a[3], RealType b[3]){ | 
| 201 | return a[0]*b[0] + a[1]*b[1]+ a[2]*b[2]; | 
| 202 | } | 
| 203 |  | 
| 204 | /*----------------------------------------------------------------------------*/ | 
| 205 | /* Extract the eigenvalues and eigenvectors from a 3x3 matrix.*/ | 
| 206 | /* The eigenvectors (the columns of V) will be normalized. */ | 
| 207 | /* The eigenvectors are aligned optimally with the x, y, and z*/ | 
| 208 | /* axes respectively.*/ | 
| 209 |  | 
| 210 | void diagonalize3x3(const RealType A[3][3], RealType w[3], RealType V[3][3]) { | 
| 211 | int i,j,k,maxI; | 
| 212 | RealType tmp, maxVal; | 
| 213 |  | 
| 214 | /* do the matrix[3][3] to **matrix conversion for Jacobi*/ | 
| 215 | RealType C[3][3]; | 
| 216 | RealType *ATemp[3],*VTemp[3]; | 
| 217 | for (i = 0; i < 3; i++) | 
| 218 | { | 
| 219 | C[i][0] = A[i][0]; | 
| 220 | C[i][1] = A[i][1]; | 
| 221 | C[i][2] = A[i][2]; | 
| 222 | ATemp[i] = C[i]; | 
| 223 | VTemp[i] = V[i]; | 
| 224 | } | 
| 225 |  | 
| 226 | /* diagonalize using Jacobi*/ | 
| 227 | JacobiN(ATemp,3,w,VTemp); | 
| 228 |  | 
| 229 | /* if all the eigenvalues are the same, return identity matrix*/ | 
| 230 | if (w[0] == w[1] && w[0] == w[2]) | 
| 231 | { | 
| 232 | identityMat3(V); | 
| 233 | return; | 
| 234 | } | 
| 235 |  | 
| 236 | /* transpose temporarily, it makes it easier to sort the eigenvectors*/ | 
| 237 | transposeMat3(V,V); | 
| 238 |  | 
| 239 | /* if two eigenvalues are the same, re-orthogonalize to optimally line*/ | 
| 240 | /* up the eigenvectors with the x, y, and z axes*/ | 
| 241 | for (i = 0; i < 3; i++) | 
| 242 | { | 
| 243 | if (w[(i+1)%3] == w[(i+2)%3]) /* two eigenvalues are the same*/ | 
| 244 | { | 
| 245 | /* find maximum element of the independant eigenvector*/ | 
| 246 | maxVal = fabs(V[i][0]); | 
| 247 | maxI = 0; | 
| 248 | for (j = 1; j < 3; j++) | 
| 249 | { | 
| 250 | if (maxVal < (tmp = fabs(V[i][j]))) | 
| 251 | { | 
| 252 | maxVal = tmp; | 
| 253 | maxI = j; | 
| 254 | } | 
| 255 | } | 
| 256 | /* swap the eigenvector into its proper position*/ | 
| 257 | if (maxI != i) | 
| 258 | { | 
| 259 | tmp = w[maxI]; | 
| 260 | w[maxI] = w[i]; | 
| 261 | w[i] = tmp; | 
| 262 | swapVectors3(V[i],V[maxI]); | 
| 263 | } | 
| 264 | /* maximum element of eigenvector should be positive*/ | 
| 265 | if (V[maxI][maxI] < 0) | 
| 266 | { | 
| 267 | V[maxI][0] = -V[maxI][0]; | 
| 268 | V[maxI][1] = -V[maxI][1]; | 
| 269 | V[maxI][2] = -V[maxI][2]; | 
| 270 | } | 
| 271 |  | 
| 272 | /* re-orthogonalize the other two eigenvectors*/ | 
| 273 | j = (maxI+1)%3; | 
| 274 | k = (maxI+2)%3; | 
| 275 |  | 
| 276 | V[j][0] = 0.0; | 
| 277 | V[j][1] = 0.0; | 
| 278 | V[j][2] = 0.0; | 
| 279 | V[j][j] = 1.0; | 
| 280 | crossProduct3(V[maxI],V[j],V[k]); | 
| 281 | normalize3(V[k]); | 
| 282 | crossProduct3(V[k],V[maxI],V[j]); | 
| 283 |  | 
| 284 | /* transpose vectors back to columns*/ | 
| 285 | transposeMat3(V,V); | 
| 286 | return; | 
| 287 | } | 
| 288 | } | 
| 289 |  | 
| 290 | /* the three eigenvalues are different, just sort the eigenvectors*/ | 
| 291 | /* to align them with the x, y, and z axes*/ | 
| 292 |  | 
| 293 | /* find the vector with the largest x element, make that vector*/ | 
| 294 | /* the first vector*/ | 
| 295 | maxVal = fabs(V[0][0]); | 
| 296 | maxI = 0; | 
| 297 | for (i = 1; i < 3; i++) | 
| 298 | { | 
| 299 | if (maxVal < (tmp = fabs(V[i][0]))) | 
| 300 | { | 
| 301 | maxVal = tmp; | 
| 302 | maxI = i; | 
| 303 | } | 
| 304 | } | 
| 305 | /* swap eigenvalue and eigenvector*/ | 
| 306 | if (maxI != 0) | 
| 307 | { | 
| 308 | tmp = w[maxI]; | 
| 309 | w[maxI] = w[0]; | 
| 310 | w[0] = tmp; | 
| 311 | swapVectors3(V[maxI],V[0]); | 
| 312 | } | 
| 313 | /* do the same for the y element*/ | 
| 314 | if (fabs(V[1][1]) < fabs(V[2][1])) | 
| 315 | { | 
| 316 | tmp = w[2]; | 
| 317 | w[2] = w[1]; | 
| 318 | w[1] = tmp; | 
| 319 | swapVectors3(V[2],V[1]); | 
| 320 | } | 
| 321 |  | 
| 322 | /* ensure that the sign of the eigenvectors is correct*/ | 
| 323 | for (i = 0; i < 2; i++) | 
| 324 | { | 
| 325 | if (V[i][i] < 0) | 
| 326 | { | 
| 327 | V[i][0] = -V[i][0]; | 
| 328 | V[i][1] = -V[i][1]; | 
| 329 | V[i][2] = -V[i][2]; | 
| 330 | } | 
| 331 | } | 
| 332 | /* set sign of final eigenvector to ensure that determinant is positive*/ | 
| 333 | if (matDet3(V) < 0) | 
| 334 | { | 
| 335 | V[2][0] = -V[2][0]; | 
| 336 | V[2][1] = -V[2][1]; | 
| 337 | V[2][2] = -V[2][2]; | 
| 338 | } | 
| 339 |  | 
| 340 | /* transpose the eigenvectors back again*/ | 
| 341 | transposeMat3(V,V); | 
| 342 | } | 
| 343 |  | 
| 344 |  | 
| 345 | #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); | 
| 346 |  | 
| 347 | #define MAX_ROTATIONS 20 | 
| 348 |  | 
| 349 | /* Jacobi iteration for the solution of eigenvectors/eigenvalues of a nxn*/ | 
| 350 | /* real symmetric matrix. Square nxn matrix a; size of matrix in n;*/ | 
| 351 | /* output eigenvalues in w; and output eigenvectors in v. Resulting*/ | 
| 352 | /* eigenvalues/vectors are sorted in decreasing order; eigenvectors are*/ | 
| 353 | /* normalized.*/ | 
| 354 | int JacobiN(RealType **a, int n, RealType *w, RealType **v) { | 
| 355 |  | 
| 356 | int i, j, k, iq, ip, numPos; | 
| 357 | int ceil_half_n; | 
| 358 | RealType tresh, theta, tau, t, sm, s, h, g, c, tmp; | 
| 359 | RealType bspace[4], zspace[4]; | 
| 360 | RealType *b = bspace; | 
| 361 | RealType *z = zspace; | 
| 362 |  | 
| 363 |  | 
| 364 | /* only allocate memory if the matrix is large*/ | 
| 365 | if (n > 4) | 
| 366 | { | 
| 367 | b = (RealType *) calloc(n, sizeof(RealType)); | 
| 368 | z = (RealType *) calloc(n, sizeof(RealType)); | 
| 369 | } | 
| 370 |  | 
| 371 | /* initialize*/ | 
| 372 | for (ip=0; ip<n; ip++) | 
| 373 | { | 
| 374 | for (iq=0; iq<n; iq++) | 
| 375 | { | 
| 376 | v[ip][iq] = 0.0; | 
| 377 | } | 
| 378 | v[ip][ip] = 1.0; | 
| 379 | } | 
| 380 | for (ip=0; ip<n; ip++) | 
| 381 | { | 
| 382 | b[ip] = w[ip] = a[ip][ip]; | 
| 383 | z[ip] = 0.0; | 
| 384 | } | 
| 385 |  | 
| 386 | /* begin rotation sequence*/ | 
| 387 | for (i=0; i<MAX_ROTATIONS; i++) | 
| 388 | { | 
| 389 | sm = 0.0; | 
| 390 | for (ip=0; ip<n-1; ip++) | 
| 391 | { | 
| 392 | for (iq=ip+1; iq<n; iq++) | 
| 393 | { | 
| 394 | sm += fabs(a[ip][iq]); | 
| 395 | } | 
| 396 | } | 
| 397 | if (sm == 0.0) | 
| 398 | { | 
| 399 | break; | 
| 400 | } | 
| 401 |  | 
| 402 | if (i < 3)                                /* first 3 sweeps*/ | 
| 403 | { | 
| 404 | tresh = 0.2*sm/(n*n); | 
| 405 | } | 
| 406 | else | 
| 407 | { | 
| 408 | tresh = 0.0; | 
| 409 | } | 
| 410 |  | 
| 411 | for (ip=0; ip<n-1; ip++) | 
| 412 | { | 
| 413 | for (iq=ip+1; iq<n; iq++) | 
| 414 | { | 
| 415 | g = 100.0*fabs(a[ip][iq]); | 
| 416 |  | 
| 417 | /* after 4 sweeps*/ | 
| 418 | if (i > 3 && (fabs(w[ip])+g) == fabs(w[ip]) | 
| 419 | && (fabs(w[iq])+g) == fabs(w[iq])) | 
| 420 | { | 
| 421 | a[ip][iq] = 0.0; | 
| 422 | } | 
| 423 | else if (fabs(a[ip][iq]) > tresh) | 
| 424 | { | 
| 425 | h = w[iq] - w[ip]; | 
| 426 | if ( (fabs(h)+g) == fabs(h)) | 
| 427 | { | 
| 428 | t = (a[ip][iq]) / h; | 
| 429 | } | 
| 430 | else | 
| 431 | { | 
| 432 | theta = 0.5*h / (a[ip][iq]); | 
| 433 | t = 1.0 / (fabs(theta)+sqrt(1.0+theta*theta)); | 
| 434 | if (theta < 0.0) | 
| 435 | { | 
| 436 | t = -t; | 
| 437 | } | 
| 438 | } | 
| 439 | c = 1.0 / sqrt(1+t*t); | 
| 440 | s = t*c; | 
| 441 | tau = s/(1.0+c); | 
| 442 | h = t*a[ip][iq]; | 
| 443 | z[ip] -= h; | 
| 444 | z[iq] += h; | 
| 445 | w[ip] -= h; | 
| 446 | w[iq] += h; | 
| 447 | a[ip][iq]=0.0; | 
| 448 |  | 
| 449 | /* ip already shifted left by 1 unit*/ | 
| 450 | for (j = 0;j <= ip-1;j++) | 
| 451 | { | 
| 452 | MAT_ROTATE(a,j,ip,j,iq) | 
| 453 | } | 
| 454 | /* ip and iq already shifted left by 1 unit*/ | 
| 455 | for (j = ip+1;j <= iq-1;j++) | 
| 456 | { | 
| 457 | MAT_ROTATE(a,ip,j,j,iq) | 
| 458 | } | 
| 459 | /* iq already shifted left by 1 unit*/ | 
| 460 | for (j=iq+1; j<n; j++) | 
| 461 | { | 
| 462 | MAT_ROTATE(a,ip,j,iq,j) | 
| 463 | } | 
| 464 | for (j=0; j<n; j++) | 
| 465 | { | 
| 466 | MAT_ROTATE(v,j,ip,j,iq) | 
| 467 | } | 
| 468 | } | 
| 469 | } | 
| 470 | } | 
| 471 |  | 
| 472 | for (ip=0; ip<n; ip++) | 
| 473 | { | 
| 474 | b[ip] += z[ip]; | 
| 475 | w[ip] = b[ip]; | 
| 476 | z[ip] = 0.0; | 
| 477 | } | 
| 478 | } | 
| 479 |  | 
| 480 | /*// this is NEVER called*/ | 
| 481 | if ( i >= MAX_ROTATIONS ) | 
| 482 | { | 
| 483 | sprintf( painCave.errMsg, | 
| 484 | "Jacobi: Error extracting eigenfunctions!\n"); | 
| 485 | painCave.isFatal = 1; | 
| 486 | simError(); | 
| 487 | return 0; | 
| 488 | } | 
| 489 |  | 
| 490 | /* sort eigenfunctions                 these changes do not affect accuracy */ | 
| 491 | for (j=0; j<n-1; j++)                  /* boundary incorrect*/ | 
| 492 | { | 
| 493 | k = j; | 
| 494 | tmp = w[k]; | 
| 495 | for (i=j+1; i<n; i++)             /* boundary incorrect, shifted already*/ | 
| 496 | { | 
| 497 | if (w[i] >= tmp)                   /* why exchage if same?*/ | 
| 498 | { | 
| 499 | k = i; | 
| 500 | tmp = w[k]; | 
| 501 | } | 
| 502 | } | 
| 503 | if (k != j) | 
| 504 | { | 
| 505 | w[k] = w[j]; | 
| 506 | w[j] = tmp; | 
| 507 | for (i=0; i<n; i++) | 
| 508 | { | 
| 509 | tmp = v[i][j]; | 
| 510 | v[i][j] = v[i][k]; | 
| 511 | v[i][k] = tmp; | 
| 512 | } | 
| 513 | } | 
| 514 | } | 
| 515 | /* insure eigenvector consistency (i.e., Jacobi can compute vectors that*/ | 
| 516 | /* are negative of one another (.707,.707,0) and (-.707,-.707,0). This can*/ | 
| 517 | /* reek havoc in hyperstreamline/other stuff. We will select the most*/ | 
| 518 | /* positive eigenvector.*/ | 
| 519 | ceil_half_n = (n >> 1) + (n & 1); | 
| 520 | for (j=0; j<n; j++) | 
| 521 | { | 
| 522 | for (numPos=0, i=0; i<n; i++) | 
| 523 | { | 
| 524 | if ( v[i][j] >= 0.0 ) | 
| 525 | { | 
| 526 | numPos++; | 
| 527 | } | 
| 528 | } | 
| 529 | /*    if ( numPos < ceil(RealType(n)/RealType(2.0)) )*/ | 
| 530 | if ( numPos < ceil_half_n) | 
| 531 | { | 
| 532 | for(i=0; i<n; i++) | 
| 533 | { | 
| 534 | v[i][j] *= -1.0; | 
| 535 | } | 
| 536 | } | 
| 537 | } | 
| 538 |  | 
| 539 | if (n > 4) | 
| 540 | { | 
| 541 | free(b); | 
| 542 | free(z); | 
| 543 | } | 
| 544 | return 1; | 
| 545 | } | 
| 546 |  | 
| 547 | #undef MAT_ROTATE | 
| 548 | #undef MAX_ROTATIONS |