Matrix: HB/well1850
Description: UNSYMMETRIC LEAST-SQUARES PROBLEM. SAUNDERS 1979.
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| (bipartite graph drawing) |
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| Matrix properties | |
| number of rows | 1,850 |
| number of columns | 712 |
| nonzeros | 8,755 |
| structural full rank? | yes |
| structural rank | 712 |
| # of blocks from dmperm | 10 |
| # strongly connected comp. | 1 |
| explicit zero entries | 3 |
| nonzero pattern symmetry | 0% |
| numeric value symmetry | 0% |
| type | real |
| structure | rectangular |
| Cholesky candidate? | no |
| positive definite? | no |
| author | M. Saunders |
| editor | I. Duff, R. Grimes, J. Lewis |
| date | 1979 |
| kind | least squares problem |
| 2D/3D problem? | no |
| Additional fields | size and type |
| b | full 1850-by-1 |
| Ordering statistics: | result |
| nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD | 83,883 |
| nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD | 9,021 |
Note that all matrix statistics (except nonzero pattern symmetry) exclude the 3 explicit zero entries.
| SVD-based statistics: | |
| norm(A) | 1.79433 |
| min(svd(A)) | 0.0161197 |
| cond(A) | 111.313 |
| rank(A) | 712 |
| 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.