Matrix: HB/watt_2
Description: UNSYMMETRIC MATRIX FROM JOHN SOMERVILLE, HERIOT-WATT. DEC,1983 H
(bipartite graph drawing) | (graph drawing of A+A') |
Matrix properties | |
number of rows | 1,856 |
number of columns | 1,856 |
nonzeros | 11,550 |
structural full rank? | yes |
structural rank | 1,856 |
# of blocks from dmperm | 65 |
# strongly connected comp. | 65 |
explicit zero entries | 0 |
nonzero pattern symmetry | 98% |
numeric value symmetry | 97% |
type | real |
structure | unsymmetric |
Cholesky candidate? | no |
positive definite? | no |
author | J. Somerville |
editor | I. Duff, R. Grimes, J. Lewis |
date | 1983 |
kind | computational fluid dynamics problem |
2D/3D problem? | yes |
Ordering statistics: | result |
nnz(chol(P*(A+A'+s*I)*P')) with AMD | 56,222 |
Cholesky flop count | 3.7e+06 |
nnz(L+U), no partial pivoting, with AMD | 110,588 |
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD | 113,884 |
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD | 208,447 |
SVD-based statistics: | |
norm(A) | 8 |
min(svd(A)) | 5.87021e-11 |
cond(A) | 1.36281e+11 |
rank(A) | 1,856 |
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.