Matrix: GHS_indef/aug2d
Description: Gould, Hu, & Scott: expanded system-2D PDE (CUTEr)
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| Matrix properties | |
| number of rows | 29,008 |
| number of columns | 29,008 |
| nonzeros | 76,832 |
| structural full rank? | no |
| structural rank | 19,208 |
| # of blocks from dmperm | 2 |
| # strongly connected comp. | 1 |
| explicit zero entries | 0 |
| nonzero pattern symmetry | symmetric |
| numeric value symmetry | symmetric |
| type | integer |
| structure | symmetric |
| Cholesky candidate? | no |
| positive definite? | no |
| author | N. Gould |
| editor | N. Gould |
| date | 1994 |
| kind | 2D/3D problem |
| 2D/3D problem? | yes |
| Ordering statistics: | result |
| nnz(chol(P*(A+A'+s*I)*P')) with AMD | 248,374 |
| Cholesky flop count | 1.1e+07 |
| nnz(L+U), no partial pivoting, with AMD | 467,740 |
| nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD | 3,305,290 |
| nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD | 602,205 |
| SVD-based statistics: | |
| norm(A) | 2.82807 |
| min(svd(A)) | 6.8258e-40 |
| cond(A) | 4.14321e+39 |
| rank(A) | 19,208 |
| sprank(A)-rank(A) | 0 |
| null space dimension | 9,800 |
| full numerical rank? | no |
| singular value gap | 5.35182e+11 |
| 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.