%-------------------------------------------------------------------------------
% UF Sparse Matrix Collection, Tim Davis
% http://www.cise.ufl.edu/research/sparse/matrices/YCheng/psse2
% name: YCheng/psse2
% [Power system state simulation matrix, Yunzhi Cheng, UT Arlington]
% id: 1872
% date: 2007
% author: Y. Cheng
% ed: T. Davis
% fields: name title A id b date author ed kind notes aux
% aux: guess
% kind: power network problem
%-------------------------------------------------------------------------------
% notes:
% Power system state simulation matrix from Yunzhi Cheng, UT Arlington.
% In MATLAB, the solution to x=A\b is desired, but this can be slow in 
% MATLAB 7.3 because of the speed of sparse QR as compared to sparse   
% Cholesky.  Using x=(A'*A)\(A'*b) is faster, but of course yields     
% slightly less accurate (but still acceptable) results.  Note that an 
% initial guess to the solution is provided, for use by an iterative   
% method.  However, sparse Cholesky with an AMD ordering is very fast  
% for this matrix and thus iterative methods are unlikely to be        
% competitive.  In MATLAB 7.3 on a 3.2 Ghz Pentium 4 desktop,          
% x=(A'*A)\(A'*b) takes 0.07 seconds.                                  
%-------------------------------------------------------------------------------
