Matrix: HB/lshp_778
Description: SYMMETRIC MATRIX FROM ALAN GEORGE'S L-SHAPE PROBLEMS, 1978.
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| Matrix properties | |
| number of rows | 778 |
| number of columns | 778 |
| nonzeros | 5,272 |
| structural full rank? | yes |
| structural rank | 778 |
| # of blocks from dmperm | 1 |
| # strongly connected comp. | 1 |
| explicit zero entries | 0 |
| nonzero pattern symmetry | symmetric |
| numeric value symmetry | symmetric |
| type | binary |
| structure | symmetric |
| Cholesky candidate? | yes |
| positive definite? | no |
| author | A. George |
| editor | I. Duff, R. Grimes, J. Lewis |
| date | 1978 |
| kind | thermal problem |
| 2D/3D problem? | yes |
| Ordering statistics: | result |
| nnz(chol(P*(A+A'+s*I)*P')) with AMD | 13,106 |
| Cholesky flop count | 3.2e+05 |
| nnz(L+U), no partial pivoting, with AMD | 25,434 |
| nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD | 16,099 |
| nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD | 29,848 |
| SVD-based statistics: | |
| norm(A) | 6.96083 |
| min(svd(A)) | 0.00106625 |
| cond(A) | 6528.36 |
| rank(A) | 778 |
| 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.