apis/examples_matlab_control/transport7_8m_source.html

function transport7(varargin)


    % check workspace info from arguments

    if nargin > 0

        wsInfo = gams.control.WorkspaceInfo();

        wsInfo.systemDirectory = varargin{1};

        ws = gams.control.Workspace(wsInfo);

    else

        ws = gams.control.Workspace();

    end


    model = {

    'Sets                                                                    '

    '      i   canning plants   / seattle, san-diego /                       '

    '      j   markets          / new-york, chicago, topeka / ;              '

    '                                                                        '

    'Parameters                                                              '

    '    a(i)  capacity of plant i in cases                                  '

    '           /    seattle     350                                         '

    '                san-diego   600  /                                      '

    '                                                                        '

    '    b(j)  demand at market j in cases                                   '

    '           /    new-york    325                                         '

    '                chicago     300                                         '

    '                topeka      275  / ;                                    '

    '                                                                        '

    'Table d(i,j)  distance in thousands of miles                            '

    '             new-york       chicago      topeka                         '

    'seattle        2.5           1.7          1.8                           '

    'san-diego      2.5           1.8          1.4  ;                        '

    '                                                                        '

    'Scalar f      freight in dollars per case per thousand miles  /90/ ;    '

    'Scalar bmult  demand multiplier /1/;                                    '

    '                                                                        '

    'Parameter c(i,j)  transport cost in thousands of dollars per case ;     '

    '          c(i,j) = f * d(i,j) / 1000 ;                                  '

    '                                                                        '

    'Variables                                                               '

    '    x(i,j)  shipment quantities in cases                                '

    '    z       total transportation costs in thousands of dollars ;        '

    '                                                                        '

    'Positive Variable x ;                                                   '

    '                                                                        '

    'Equations                                                               '

    '      cost        define objective function                             '

    '      supply(i)   observe supply limit at plant i                       '

    '      demand(j)   satisfy demand at market j ;                          '

    '                                                                        '

    '  cost ..        z  =e=  sum((i,j), c(i,j)*x(i,j)) ;                    '

    '                                                                        '

    '  supply(i) ..   sum(j, x(i,j))  =l=  a(i) ;                            '

    '                                                                        '

    '  demand(j) ..   sum(i, x(i,j))  =g=  bmult*b(j) ;                      '

    '                                                                        '

    'Model transport /all/ ;                                                 '

    '                                                                        '};

    model = sprintf('%s\n', model{:});


    % create a checkpoint

    cp = ws.addCheckpoint();


    % initialize a checkpoint by running a job

    t7 = ws.addJobFromString(model);

    t7.run(cp);


    % create a ModelInstance and solve it multiple times with different scalar bmult

    mi = cp.addModelInstance();

    bmult = mi.syncDB.addParameter('bmult', 'demand multiplier');

    opt = ws.addOptions();

    opt.setAllModelTypes('cplex');


    % instantiate the ModelInstance and pass a model definition and Modifier to declare bmult mutable

    mi.instantiate('transport use lp min z', opt, gams.control.Modifier(bmult));


    rec = bmult.addRecord();

    rec.value = 1.0;

    bmultlist = [0.6, 0.7 , 0.8, 0.9, 1.0, 1.1, 1.2, 1.3];


    for i = 1:numel(bmultlist)

        rec.value = bmultlist(i);

        mi.solve();


        fprintf('Scenario bmult=%f:\n', bmultlist(i));

        fprintf('  Modelstatus: %s\n', mi.modelStatus.select);

        fprintf('  Solvestatus: %s\n', mi.solveStatus.select);

        fprintf('  Obj: %f\n', mi.syncDB.getVariable('z').record.level);

    end


    % clear ModelInstance

    mi.dispose();


    % create a ModelInstance and solve it with single links in the network blocked

    mi = cp.addModelInstance();


    x = mi.syncDB.addVariable('x', 2, gams.control.globals.VarType.POSITIVE, '');

    xup = mi.syncDB.addParameter('xup', 2, 'upper bound on x');


    % instantiate the ModelInstance and pass a model definition and Modifier to declare upper bound of X mutable

    mi.instantiate('transport use lp min z', gams.control.Modifier(x, gams.control.globals.UpdateAction.UPPER, xup));


    for i = t7.outDB.getSet('i').records

        for j = t7.outDB.getSet('j').records

            xup.clear();

            keys = {i{1}.key(1), j{1}.key(1)};

            rec = xup.addRecord(keys);

            rec.value = 0;

            mi.solve();


            fprintf('Scenario link blocked: %s - %s\n', keys{:});

            fprintf('  Modelstatus: %s\n', mi.modelStatus.select);

            fprintf('  Solvestatus: %s\n', mi.solveStatus.select);

            fprintf('  Obj: %f\n', mi.syncDB.getVariable('z').record.level);

        end

    end


    % clear ModelInstance

    mi.dispose();


    % clear database

    t7.outDB.dispose();


    % remove working directory

    rmdir(ws.workingDirectory, 's');

end