Reduction of a symmetric matrix which is given by its higher or lower triangular part to a tridiagonal matrix using orthogonal similarity transformation: Q'*A*Q=T. Input parameters: A - matrix to be transformed array with elements [0..N-1, 0..N-1]. N - size of matrix A. IsUpper - storage format. If IsUpper = True, then matrix A is given
| 2309 | October 31, 1992 |
| 2310 | *************************************************************************/ |
| 2311 | void smatrixtd(ap::real_2d_array& a, |
| 2312 | int n, |
| 2313 | bool isupper, |
| 2314 | ap::real_1d_array& tau, |
| 2315 | ap::real_1d_array& d, |
| 2316 | ap::real_1d_array& e) |
| 2317 | { |
| 2318 | int i; |
| 2319 | double alpha; |
| 2320 | double taui; |
| 2321 | double v; |
| 2322 | ap::real_1d_array t; |
| 2323 | ap::real_1d_array t2; |
| 2324 | ap::real_1d_array t3; |
| 2325 | |
| 2326 | if( n<=0 ) |
| 2327 | { |
| 2328 | return; |
| 2329 | } |
| 2330 | t.setbounds(1, n); |
| 2331 | t2.setbounds(1, n); |
| 2332 | t3.setbounds(1, n); |
| 2333 | if( n>1 ) |
| 2334 | { |
| 2335 | tau.setbounds(0, n-2); |
| 2336 | } |
| 2337 | d.setbounds(0, n-1); |
| 2338 | if( n>1 ) |
| 2339 | { |
| 2340 | e.setbounds(0, n-2); |
| 2341 | } |
| 2342 | if( isupper ) |
| 2343 | { |
| 2344 | |
| 2345 | // |
| 2346 | // Reduce the upper triangle of A |
| 2347 | // |
| 2348 | for(i = n-2; i >= 0; i--) |
| 2349 | { |
| 2350 | |
| 2351 | // |
| 2352 | // Generate elementary reflector H() = E - tau * v * v' |
| 2353 | // |
| 2354 | if( i>=1 ) |
| 2355 | { |
| 2356 | ap::vmove(&t(2), 1, &a(0, i+1), a.getstride(), ap::vlen(2,i+1)); |
| 2357 | } |
| 2358 | t(1) = a(i,i+1); |
| 2359 | generatereflection(t, i+1, taui); |
| 2360 | if( i>=1 ) |
| 2361 | { |
| 2362 | ap::vmove(&a(0, i+1), a.getstride(), &t(2), 1, ap::vlen(0,i-1)); |
| 2363 | } |
| 2364 | a(i,i+1) = t(1); |
| 2365 | e(i) = a(i,i+1); |
| 2366 | if( ap::fp_neq(taui,0) ) |
| 2367 | { |
| 2368 |
nothing calls this directly
no test coverage detected