| 78 |  | return m; | 
| 79 |  | } | 
| 80 |  |  | 
| 81 | < | /** Retunrs  the inversion of this matrix. */ | 
| 81 | > | /** | 
| 82 | > | * Retunrs  the inversion of this matrix. | 
| 83 | > | * @todo | 
| 84 | > | */ | 
| 85 |  | SquareMatrix<Real, Dim>  inverse() { | 
| 86 |  | SquareMatrix<Real, Dim> result; | 
| 87 |  |  | 
| 88 |  | return result; | 
| 89 | < | } | 
| 89 | > | } | 
| 90 |  |  | 
| 91 | < |  | 
| 92 | < |  | 
| 93 | < | /** Returns the determinant of this matrix. */ | 
| 91 | > | /** | 
| 92 | > | * Returns the determinant of this matrix. | 
| 93 | > | * @todo | 
| 94 | > | */ | 
| 95 |  | double determinant() const { | 
| 96 |  | double det; | 
| 97 |  | return det; | 
| 117 |  | return true; | 
| 118 |  | } | 
| 119 |  |  | 
| 120 | < | /** Tests if this matrix is orthogona. */ | 
| 120 | > | /** Tests if this matrix is orthogonal. */ | 
| 121 |  | bool isOrthogonal() { | 
| 122 |  | SquareMatrix<Real, Dim> tmp; | 
| 123 |  |  | 
| 124 |  | tmp = *this * transpose(); | 
| 125 |  |  | 
| 126 | < | return tmp.isUnitMatrix(); | 
| 126 | > | return tmp.isDiagonal(); | 
| 127 |  | } | 
| 128 |  |  | 
| 129 |  | /** Tests if this matrix is diagonal. */ | 
| 148 |  | return true; | 
| 149 |  | } | 
| 150 |  |  | 
| 151 | + | /** @todo need implement */ | 
| 152 | + | void diagonalize() { | 
| 153 | + | //jacobi(m, eigenValues, ortMat); | 
| 154 | + | } | 
| 155 | + |  | 
| 156 | + | /** | 
| 157 | + | * Finds the eigenvalues and eigenvectors of a symmetric matrix | 
| 158 | + | * @param eigenvals a reference to a vector3 where the | 
| 159 | + | * eigenvalues will be stored. The eigenvalues are ordered so | 
| 160 | + | * that eigenvals[0] <= eigenvals[1] <= eigenvals[2]. | 
| 161 | + | * @return an orthogonal matrix whose ith column is an | 
| 162 | + | * eigenvector for the eigenvalue eigenvals[i] | 
| 163 | + | */ | 
| 164 | + | SquareMatrix<Real, Dim>  findEigenvectors(Vector<Real, Dim>& eigenValues) { | 
| 165 | + | SquareMatrix<Real, Dim> ortMat; | 
| 166 | + |  | 
| 167 | + | if ( !isSymmetric()){ | 
| 168 | + | throw(); | 
| 169 | + | } | 
| 170 | + |  | 
| 171 | + | SquareMatrix<Real, Dim> m(*this); | 
| 172 | + | jacobi(m, eigenValues, ortMat); | 
| 173 | + |  | 
| 174 | + | return ortMat; | 
| 175 | + | } | 
| 176 | + | /** | 
| 177 | + | * Jacobi iteration routines for computing eigenvalues/eigenvectors of | 
| 178 | + | * real symmetric matrix | 
| 179 | + | * | 
| 180 | + | * @return true if success, otherwise return false | 
| 181 | + | * @param a source matrix | 
| 182 | + | * @param w output eigenvalues | 
| 183 | + | * @param v output eigenvectors | 
| 184 | + | */ | 
| 185 | + | bool jacobi(const SquareMatrix<Real, Dim>& a, Vector<Real, Dim>& w, | 
| 186 | + | SquareMatrix<Real, Dim>& v); | 
| 187 |  | };//end SquareMatrix | 
| 188 |  |  | 
| 189 | + |  | 
| 190 | + | #define ROT(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) | 
| 191 | + | #define MAX_ROTATIONS 60 | 
| 192 | + |  | 
| 193 | + | template<typename Real, int Dim> | 
| 194 | + | bool SquareMatrix<Real, Dim>::jacobi(const SquareMatrix<Real, Dim>& a, Vector<Real, Dim>& w, | 
| 195 | + | SquareMatrix<Real, Dim>& v) { | 
| 196 | + | const int N = Dim; | 
| 197 | + | int i, j, k, iq, ip; | 
| 198 | + | double tresh, theta, tau, t, sm, s, h, g, c; | 
| 199 | + | double tmp; | 
| 200 | + | Vector<Real, Dim> b, z; | 
| 201 | + |  | 
| 202 | + | // initialize | 
| 203 | + | for (ip=0; ip<N; ip++) { | 
| 204 | + | for (iq=0; iq<N; iq++) | 
| 205 | + | v(ip, iq) = 0.0; | 
| 206 | + | v(ip, ip) = 1.0; | 
| 207 | + | } | 
| 208 | + |  | 
| 209 | + | for (ip=0; ip<N; ip++) { | 
| 210 | + | b(ip) = w(ip) = a(ip, ip); | 
| 211 | + | z(ip) = 0.0; | 
| 212 | + | } | 
| 213 | + |  | 
| 214 | + | // begin rotation sequence | 
| 215 | + | for (i=0; i<MAX_ROTATIONS; i++) { | 
| 216 | + | sm = 0.0; | 
| 217 | + | for (ip=0; ip<2; ip++) { | 
| 218 | + | for (iq=ip+1; iq<N; iq++) | 
| 219 | + | sm += fabs(a(ip, iq)); | 
| 220 | + | } | 
| 221 | + |  | 
| 222 | + | if (sm == 0.0) | 
| 223 | + | break; | 
| 224 | + |  | 
| 225 | + | if (i < 4) | 
| 226 | + | tresh = 0.2*sm/(9); | 
| 227 | + | else | 
| 228 | + | tresh = 0.0; | 
| 229 | + |  | 
| 230 | + | for (ip=0; ip<2; ip++) { | 
| 231 | + | for (iq=ip+1; iq<N; iq++) { | 
| 232 | + | g = 100.0*fabs(a(ip, iq)); | 
| 233 | + | if (i > 4 && (fabs(w(ip))+g) == fabs(w(ip)) | 
| 234 | + | && (fabs(w(iq))+g) == fabs(w(iq))) { | 
| 235 | + | a(ip, iq) = 0.0; | 
| 236 | + | } else if (fabs(a(ip, iq)) > tresh) { | 
| 237 | + | h = w(iq) - w(ip); | 
| 238 | + | if ( (fabs(h)+g) == fabs(h)) { | 
| 239 | + | t = (a(ip, iq)) / h; | 
| 240 | + | } else { | 
| 241 | + | theta = 0.5*h / (a(ip, iq)); | 
| 242 | + | t = 1.0 / (fabs(theta)+sqrt(1.0+theta*theta)); | 
| 243 | + |  | 
| 244 | + | if (theta < 0.0) | 
| 245 | + | t = -t; | 
| 246 | + | } | 
| 247 | + |  | 
| 248 | + | c = 1.0 / sqrt(1+t*t); | 
| 249 | + | s = t*c; | 
| 250 | + | tau = s/(1.0+c); | 
| 251 | + | h = t*a(ip, iq); | 
| 252 | + | z(ip) -= h; | 
| 253 | + | z(iq) += h; | 
| 254 | + | w(ip) -= h; | 
| 255 | + | w(iq) += h; | 
| 256 | + | a(ip, iq)=0.0; | 
| 257 | + |  | 
| 258 | + | for (j=0;j<ip-1;j++) | 
| 259 | + | ROT(a,j,ip,j,iq); | 
| 260 | + |  | 
| 261 | + | for (j=ip+1;j<iq-1;j++) | 
| 262 | + | ROT(a,ip,j,j,iq); | 
| 263 | + |  | 
| 264 | + | for (j=iq+1; j<N; j++) | 
| 265 | + | ROT(a,ip,j,iq,j); | 
| 266 | + |  | 
| 267 | + | for (j=0; j<N; j++) | 
| 268 | + | ROT(v,j,ip,j,iq); | 
| 269 | + | } | 
| 270 | + | } | 
| 271 | + | }//for (ip=0; ip<2; ip++) | 
| 272 | + |  | 
| 273 | + | for (ip=0; ip<N; ip++) { | 
| 274 | + | b(ip) += z(ip); | 
| 275 | + | w(ip) = b(ip); | 
| 276 | + | z(ip) = 0.0; | 
| 277 | + | } | 
| 278 | + |  | 
| 279 | + | } // end for (i=0; i<MAX_ROTATIONS; i++) | 
| 280 | + |  | 
| 281 | + | if ( i >= MAX_ROTATIONS ) | 
| 282 | + | return false; | 
| 283 | + |  | 
| 284 | + | // sort eigenfunctions | 
| 285 | + | for (j=0; j<N; j++) { | 
| 286 | + | k = j; | 
| 287 | + | tmp = w(k); | 
| 288 | + | for (i=j; i<N; i++) { | 
| 289 | + | if (w(i) >= tmp) { | 
| 290 | + | k = i; | 
| 291 | + | tmp = w(k); | 
| 292 | + | } | 
| 293 | + | } | 
| 294 | + |  | 
| 295 | + | if (k != j) { | 
| 296 | + | w(k) = w(j); | 
| 297 | + | w(j) = tmp; | 
| 298 | + | for (i=0; i<N; i++)  { | 
| 299 | + | tmp = v(i, j); | 
| 300 | + | v(i, j) = v(i, k); | 
| 301 | + | v(i, k) = tmp; | 
| 302 | + | } | 
| 303 | + | } | 
| 304 | + | } | 
| 305 | + |  | 
| 306 | + | //    insure eigenvector consistency (i.e., Jacobi can compute | 
| 307 | + | //    vectors that are negative of one another (.707,.707,0) and | 
| 308 | + | //    (-.707,-.707,0). This can reek havoc in | 
| 309 | + | //    hyperstreamline/other stuff. We will select the most | 
| 310 | + | //    positive eigenvector. | 
| 311 | + | int numPos; | 
| 312 | + | for (j=0; j<N; j++) { | 
| 313 | + | for (numPos=0, i=0; i<N; i++) if ( v(i, j) >= 0.0 ) numPos++; | 
| 314 | + | if ( numPos < 2 ) for(i=0; i<N; i++) v(i, j) *= -1.0; | 
| 315 | + | } | 
| 316 | + |  | 
| 317 | + | return true; | 
| 318 |  | } | 
| 319 | + |  | 
| 320 | + | #undef ROT | 
| 321 | + | #undef MAX_ROTATIONS | 
| 322 | + |  | 
| 323 | + | } | 
| 324 | + |  | 
| 325 |  | #endif //MATH_SQUAREMATRIX_HPP |