Matrix: GHS_indef/helm3d01
Description: Helmholtz eq. on a unit cube: -div grad u -10000 u = 1, B.C. u = 0
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| Matrix properties | |
| number of rows | 32,226 |
| number of columns | 32,226 |
| nonzeros | 428,444 |
| structural full rank? | yes |
| structural rank | 32,226 |
| # of blocks from dmperm | 1 |
| # strongly connected comp. | 1 |
| explicit zero entries | 0 |
| nonzero pattern symmetry | symmetric |
| numeric value symmetry | symmetric |
| type | real |
| structure | symmetric |
| Cholesky candidate? | no |
| positive definite? | no |
| author | |
| editor | N. Gould, Y. Hu, J. Scott |
| date | 2004 |
| kind | 2D/3D problem |
| 2D/3D problem? | yes |
| Ordering statistics: | result |
| nnz(chol(P*(A+A'+s*I)*P')) with AMD | 7,709,021 |
| Cholesky flop count | 8.3e+09 |
| nnz(L+U), no partial pivoting, with AMD | 15,385,816 |
| nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD | 23,546,358 |
| nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD | 45,839,308 |
| SVD-based statistics: | |
| norm(A) | 0.505218 |
| min(svd(A)) | 2.06052e-06 |
| cond(A) | 245190 |
| rank(A) | 32,226 |
| sprank(A)-rank(A) | 0 |
| null space dimension | 0 |
| full numerical rank? | yes |
| singular values (MAT file): | click here |
| SVD method used: | s = svd (full (A)) |
| status: | ok |
For a description of the statistics displayed above, click here.
Maintained by Tim Davis, last updated 12-Mar-2014.
Matrix pictures by cspy, a MATLAB function in the CSparse package.
Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.