lpmod.m
这个例子从一个文件中读取一个LP模型并解决它。狗万app足彩如果模型可以被求解，那么它会找到最小的正变量，将它的上界设为零，并以两种方式解析模型:%首先有一个高级的开始，然后没有高级的开始%(即“从头开始”)。%读取模型fprintf('读取模型%s\n'，文件名);模型= gurobi_read(文件名);If (isfield(model， 'multiobj') && ~isempty(model.multiobj)) ||…(isfield(模型、“sos”)& & ~ isempty (model.sos)) | |…(isfield(模型、pwlobj) & & ~ isempty (model.pwlobj)) | |…(isfield(model， 'quadcon') && ~isempty(model.quadcon)) ||…(isfield(model， 'genconstr') && ~isempty(model.genconstr)) ||… isfield(model, 'Q') fprintf('The model is not a linear program, quit\n'); return; end ivars = find(model.vtype ~= 'C'); ints = length(ivars); if ints > 0 fprintf('problem is a MIP, quit\n'); return; end result = gurobi(model); if ~strcmp(result.status, 'OPTIMAL') fprintf('This model cannot be solved because its optimization status is %s\n', result.status); return; end cols = size(model.A,2); % create lb if they do not exists, and set them to default values if ~isfield(model, 'lb') || isempty(model.lb) model.lb = zeros(cols, 1); end % Find the smallest variable value minVal = inf; minVar = -1; for j = 1:cols if result.x(j) > 0.0001 && result.x(j) < minVal && model.lb(j) == 0.0 minVal = result.x(j); minVar = j; end end fprintf('\n*** Setting %s from %d to zero ***\n', model.varnames{minVar}, minVar); model.ub(minVar) = 0; model.vbasis = result.vbasis; model.cbasis = result.cbasis; % Solve from this starting point result = gurobi(model); % Save iteration & time info warmCount = result.itercount; warmTime = result.runtime; % Remove warm start basis and resolve model = rmfield(model, 'vbasis'); model = rmfield(model, 'cbasis'); result = gurobi(model); coldCount = result.itercount; coldTime = result.runtime; fprintf('\n'); fprintf('*** Warm start: %g iterations, %g seconds\n', warmCount, warmTime); fprintf('*** Cold start: %g iterations, %g seconds\n', coldCount, coldTime);
