Matrix: GHS_psdef/pwt
Description: PWT: Nasa matrix, but with a diagonal added to the original matrix
(undirected graph drawing) |
Matrix properties | |
number of rows | 36,519 |
number of columns | 36,519 |
nonzeros | 326,107 |
structural full rank? | yes |
structural rank | 36,519 |
# of blocks from dmperm | 57 |
# strongly connected comp. | 57 |
explicit zero entries | 0 |
nonzero pattern symmetry | symmetric |
numeric value symmetry | symmetric |
type | binary |
structure | symmetric |
Cholesky candidate? | yes |
positive definite? | no |
author | NASA |
editor | G. Kumfert, A. Pothen |
date | 1995 |
kind | duplicate structural problem |
2D/3D problem? | yes |
Notes:
Nasa/pwt, GHS_psdef/pwt and Pothen/pwt are identical; Pothen/ has xyz coord.
Ordering statistics: | result |
nnz(chol(P*(A+A'+s*I)*P')) with AMD | 1,555,833 |
Cholesky flop count | 1.6e+08 |
nnz(L+U), no partial pivoting, with AMD | 3,075,147 |
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD | 2,667,503 |
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD | 5,000,519 |
SVD-based statistics: | |
norm(A) | 9.90527 |
min(svd(A)) | 8.72467e-19 |
cond(A) | 1.13532e+19 |
rank(A) | 35,475 |
sprank(A)-rank(A) | 1,044 |
null space dimension | 1,044 |
full numerical rank? | no |
singular value gap | 4.30451e+09 |
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.