%-------------------------------------------------------------------------------
% UF Sparse Matrix Collection, Tim Davis
% http://www.cise.ufl.edu/research/sparse/matrices/Koutsovasilis/F2
% name: Koutsovasilis/F2
% [AUDI engine piston rod; Panos Koutsovasilis, Technische Univ. Dresden]
% id: 1861
% date: 2007
% author: P. Koutsovasilis
% ed: T. Davis
% fields: name title A id date author ed kind notes
% kind: structural problem
%-------------------------------------------------------------------------------
% notes:
% Stiffness matrix from an AUDI engine piston rod.  This matrix is an ill-     
% condition symmetric indefinite matrix.  In MATLAB 7.4, the matrix is         
% factorized three times in x=A\b.  Inside backslash, CHOLMOD is tried first   
% since the matrix is symmetric and all diagonal entries are positive.  CHOLMOD
% fails since the matrix is indefinite.  Next, UMFPACK is used with default    
% pivot tolerances which maintain sparsity at the (rare) expense of a slight   
% decrease in accuracy.  This succeeds, but the result is flagged as           
% potentially inaccurate because the condition estimate is high.  UMFPACK is   
% then used again with more conservative tolerances (but more fill-in).        
%-------------------------------------------------------------------------------
