From viktor.haerter at tuhh.de  Wed Aug 10 07:27:18 2011
From: viktor.haerter at tuhh.de (Viktor Haerter)
Date: Wed, 10 Aug 2011 13:27:18 +0200
Subject: [Csdp-tickets] Check of symmetry
Message-ID: <4E426B16.9070807@tuhh.de>

Dear developers of CSDP, I'm very glad about CSDP at all (results, 
accuracy, computin time), but a small trouble is, that CSDP checks 
without any exception, if a given matrice is a symmetric matrice. In 
older version of CSDP, there was a parameter "parm.check", to say to 
CSDP that the given matrices are symmetric and CSDP should not check the 
symmetry property again. Now it is as here: (see file writesdpa)

line 435 and below...

     work=sparse(II,ones(size(II)),rowcn(I),K.s(i)^2,1);

     work=reshape(work,K.s(i),K.s(i));

     if (norm(work-work','fro') ~= 0)
       if (quiet==0)
         fprintf('Non symmetric A.s matrix! \n');
       end
       work=(work+work')/2;
     end
%
% Ignore the lower left triangle.
%
     work=triu(work);


So if I already give to CSDP only the upper part of a symmetric matrice, 
CSDP first creates a symmetric matrice again and then take the upper 
part of it. It can take much time for some problems!!! And this is not 
very well approach. May be it would be desireable to introduce the 
"parm.check" option again, to circumvent this trouble.

With the best regards!
Victor