Description: real matrix from aero research, David Young, corrected RUA version
|(bipartite graph drawing)||(graph drawing of A+A')|
|number of rows||841|
|number of columns||841|
|structural full rank?||yes|
|# of blocks from dmperm||1|
|# strongly connected comp.||1|
|explicit zero entries||0|
|nonzero pattern symmetry||94%|
|numeric value symmetry||81%|
|editor||I. Duff, R. Grimes, J. Lewis|
The YOUNG*C matrices originally appeared in the Harwell/Boeing collection as type CSA (complex symmetric). However, both upper and lower triangular parts are present in the original files (an invalid specification; only the lower part can be present in the file). If the entries in the upper triangular part are considered as part of the matrix, the matrices become unsymmetric. The matrices have been corrected in the UF Sparse Matrix Collection by changing their type to CUA so that the entries in the original files are not ignored. In addition, the YOUNG3C matrix has a zero imaginary part, and thus appears here as a real matrix.
|nnz(chol(P*(A+A'+s*I)*P')) with AMD||9,467|
|Cholesky flop count||1.7e+05|
|nnz(L+U), no partial pivoting, with AMD||18,093|
|nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD||14,058|
|nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD||25,278|
|null space dimension||0|
|full numerical rank?||yes|
|singular values (MAT file):||click here|
|SVD method used:||s = svd (full (A)) ;|
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.