Matrix: GHS_indef/c-68
Description: Schenk: IBM TJ Watson, Yorktown, nonlinear optimization
| Matrix properties | |
| number of rows | 64,810 |
| number of columns | 64,810 |
| nonzeros | 565,996 |
| structural full rank? | yes |
| structural rank | 64,810 |
| # of blocks from dmperm | 6 |
| # strongly connected comp. | 6 |
| entries not in dmperm blocks | 15 |
| explicit zero entries | 10 |
| nonzero pattern symmetry | symmetric |
| numeric value symmetry | symmetric |
| type | real |
| structure | symmetric |
| Cholesky candidate? | no |
| positive definite? | no |
| author | IBM |
| editor | O. Schenk |
| date | 2004 |
| kind | optimization problem |
| 2D/3D problem? | no |
| Additional fields | size and type |
| b | full 64810-by-1 |
Notes:
Revised Nov 2006; relative eps changes to A, right-hand-side added. Note that this matrix should have been placed in the Schenk_IBMNA/ directory when it was first added in August 2004, but moving it now would disrupt exising users of the collection.
| Ordering statistics: | AMD | METIS | DMPERM+ |
| nnz(chol(P*(A+A'+s*I)*P')) | 6,523,400 | 5,144,147 | 5,413,032 |
| Cholesky flop count | 1.2e+10 | 5.0e+09 | 5.5e+09 |
| nnz(L+U), no partial pivoting | 12,981,990 | 10,223,484 | 10,761,269 |
| nnz(V) for QR, upper bound nnz(L) for LU | 70,689,995 | 36,068,324 | 34,302,462 |
| nnz(R) for QR, upper bound nnz(U) for LU | 115,405,123 | 72,517,805 | 71,813,196 |
Note that all matrix statistics (except nonzero pattern symmetry) exclude the 10 explicit zero entries.
Maintained by Tim Davis, last updated 30-Sep-2008.
Matrix pictures by cspy, a MATLAB function in the CSparse package.
Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.