function quiz2 = plus(a,b)% SDMPB/PLUS - add a constant term to all inequality constraints of an LM problem%%   quiz2=plus(quiz1,s) performs quiz2=quiz1+s%%   where <quiz1> and <quiz2> are SDMPB objects (LMC problems)%   and <s> is a scalar%   The operation adds a constant term %   to all inequality constraints of the LMC problem.%   This constant term is <s> times the identity matrix.%   L(u)>=0   becomes   L(u)+s*I>=0  %% SEE ALSO sdmpb/minus  %   This file is part of SeDuMi Interface 1.04 (JUL2002)%   Last update : 6th September 2002%   Copyright (C) 2002 Dimitri Peaucelle & Krysten Taitz%   LAAS-CNRS, Toulouse, France% %   This program is free software; you can redistribute it and/or modify%   it under the terms of the GNU General Public License as published by%   the Free Software Foundation; either version 2 of the License, or%   (at your option) any later version.% %   This program is distributed in the hope that it will be useful,%   but WITHOUT ANY WARRANTY; without even the implied warranty of%   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the%   GNU General Public License for more details.% %   You should have received a copy of the GNU General Public License%   along with this program; if not, write to the Free Software%   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.       %%% check inputs  if nargin~=2    error('needs two input arguments');  elseif isa(a,'sdmpb')    quiz1=a;    s=b;  elseif isa(b,'sdmpb')    quiz1=b;    s=a;  end;  if ~isnumeric(s)    error('can only add a scalar to an SDMPB object');  elseif max([1,1]~=size(s))    error('can only add a scalar to an SDMPB object');  elseif ~isreal(s)    error('can only add a real valued scalar to an SDMPB object');  end;  %%% clear the previous solution if necessary and add the constant term  quiz2=quiz1;  if s % clear and change only if s is not zero    quiz2 = sdmclear(quiz2);    for ii=1:quiz2.ineq.nb      quiz2.ineq.meig{ii}=-Inf;      lmim=quiz2.ineq.m(ii);      lmiM=quiz2.ineq.M(ii);      dim=sqrt(lmiM-lmim+1);      quiz2.ineq.c(lmim:lmiM,:)=quiz2.ineq.c(lmim:lmiM,:)+s*sdmvec(speye(dim));    end;  end;