plus.m

这是matlab解2阶锥工具包

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;