source: proiecte/pmake3d/make3d_original/Make3dSingleImageStanford_version0.1/third_party/opt/yalmip/extras/savesdpafile.m @ 37

function solution = savesdpafile(varargin)
%SAVESDPAFILE Saves a problem definition in the SDPA format
%
%    SAVESDPAFILE(F,h,'filename')    Saves the problem min(h(x)), F(x)>0 to the file filename
%    SAVESDPAFILE(F,h)               A "Save As" - box will be opened                               

% Author Johan Löfberg
% $Id: savesdpafile.m,v 1.5 2005/09/27 10:21:32 joloef Exp $

F = varargin{1};
h = varargin{2};
nvars = yalmip('nvars');

% Expand nonlinear operators
[F,failure,cause] = expandmodel(F,h,sdpsettings);
if failure % Convexity propgation failed
    interfacedata = [];
    recoverdata = [];
    solver = '';
    diagnostic.solvertime = 0;
    diagnostic.problem = 14;
    diagnostic.info = yalmiperror(14,cause);
    return
end

% Get the SP format
[F_struc,K]  = lmi2sedumistruct(F,[]);

% Convert the objective
if isempty(h)
        c=zeros(nvars,1);
else  
        [n,m]=size(h);
        if ~((n==1) & (m==1))
                error('Scalar expression to minimize please.');
        else
                lmi_variables = getvariables(h);
                c  = zeros(nvars,1);
                for i=1:length(lmi_variables)
                        c(lmi_variables(i))=getbasematrix(h,lmi_variables(i));
                end;
        end
end

% Which sdpvar variables are actually in the problem
used_variables_LMI = find(any(F_struc(:,2:end),1));
used_variables_obj = find(any(c',1));
used_variables = uniquestripped([used_variables_LMI used_variables_obj]);

% Check for unbounded variables
unbounded_variables = setdiff(used_variables_obj,used_variables_LMI);
if ~isempty(unbounded_variables)
        % Remove unbounded variable from problem
        used_variables = setdiff(used_variables,unbounded_variables);
end

% Pick out the necessary rows
if length(used_variables)<nvars
        c = c(used_variables);
        F_struc = sparse(F_struc(:,[1 1+[used_variables]]));
end

if K.f>0
        % Extract the inequalities
        A_equ = F_struc(1:K.f,2:end);
        b_equ = -F_struc(1:K.f,1);
        [Q,R] = qr(A_equ');
        n = max(find(any(R')));
        Q1 = Q(:,1:n);
        Q2 = Q(:,n+1:end); 
        R = R(1:n,:);
        x_equ = Q1*(R'\b_equ);  
        % Exit if no consistent solution exist
        if (norm(A_equ*x_equ-b_equ)>sqrt(eps))
                error('Linear constraints inconsistent.');
                return
        end
        % So we dont need these rows anymore
        F_struc = F_struc(K.f+1:end,:);
        K.f = 0;
        % OK, we found a new basis
        H = Q2;
        % objective in new basis
        c = H'*c;
        % LMI in new basis
        F_struc = [F_struc*[1;x_equ] F_struc(:,2:end)*H];
end

% Is a filename supplied
if nargin<3
        [filename, pathname] = uiputfile('*.dat-s', 'Save SDPA sparse format file');
        if isa(filename,'double')
                return % User canceled
        else
                % Did the user change the extension
                if isempty(findstr(filename,'.'))
                        filename = [pathname filename '.dat-s'];
                else
                        filename = [pathname filename];
                end     
        end
else
        filename = varargin{3};
end

% Save to file
createsdplibfile(F_struc, K, c, filename);