Matrix properties
number of rows	37,365
number of columns	37,365
nonzeros	330,633
structural full rank?	yes
structural rank	37,365
# of blocks from dmperm	1
# strongly connected comp.	1
explicit zero entries	0
nonzero pattern symmetry	99%
numeric value symmetry	71%
type	complex
structure	unsymmetric
Cholesky candidate?	no
positive definite?	no

author	J. Washbourne
editor	T. Davis
date	2012
kind	2D/3D problem
2D/3D problem?	no

Notes:

Complex unsymmetric matrix arising from a 2D Helmholtz formulation
for temporal frequency domain seismic modeling.                   
From John Washbourne, Chevron                                     

Ordering statistics:	result
nnz(chol(P*(A+A'+s*I)*P')) with AMD	1,687,266
Cholesky flop count	2.5e+08
nnz(L+U), no partial pivoting, with AMD	3,337,167
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	2,464,508
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	4,693,946

SVD-based statistics:
norm(A)	0.0519261
min(svd(A))	5.20932e-07
cond(A)	99679.1
rank(A)	37,365
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.