Matrix properties
number of rows	377,002
number of columns	377,002
nonzeros	27,582,698
structural full rank?	yes
structural rank	377,002
# of blocks from dmperm	2,503
# strongly connected comp.	2,503
explicit zero entries	107,274
nonzero pattern symmetry	symmetric
numeric value symmetry	0%
type	real
structure	unsymmetric
Cholesky candidate?	no
positive definite?	no

author	C. Janna, M. Ferronato, G. Pini
editor	T. Davis
date	2012
kind	structural problem
2D/3D problem?	yes

Notes:

Authors: Carlo Janna, Massimiliano Ferronato, Giorgio Pini       
Matrix type: Unsymmetric                                         
# equations:       377,002                                       
# non-zeroes:   27,689,972                                       
                                                                 
Problem description: Poisson problem                             
                                                                 
The matrix ML_Laplace has been obtained by discretizing a 2D     
Poisson equation with a Meshless Local Petrov-Galerkin method.   
                                                                 
Further information can be found in the following papers:        
                                                                 
1) G. Pini, A. Mazzia, and F. Sartoretto. Accurate MLPG solution 
of 3D potential problems. CMES - Computer Modeling in Engineering
& Sciences 36 (2008), pp. 43-64.                                 
                                                                 
2) M. Ferronato, C. Janna and G. Pini. A generalized Block FSAI  
preconditioner for unsymmetric indefinite matrices. Journal of   
Computational and Applied Mathematics (2012), submitted.         

Ordering statistics:	result
nnz(chol(P*(A+A'+s*I)*P')) with AMD	284,522,480
Cholesky flop count	5.0e+11
nnz(L+U), no partial pivoting, with AMD	568,667,958
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	455,980,664
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	899,086,831

Note that all matrix statistics (except nonzero pattern symmetry) exclude the 107274 explicit zero entries.

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.