Method load

code/math/linear_program_io.cpp:244–348

bool LinearProgram::load(const std::string& file_name) {
	if (!details::is_file(file_name)) {
		std::cerr << "file does not exist: \'" << file_name << "\'" << std::endl;
		return false;
	}

	clear();

	const std::string& ext = details::extension(file_name);
	if (ext != "lp" && ext != "mps" && ext != "cip") {
		std::cerr << "unsupported format: \'" << ext << "\'" << std::endl;
		return false;
	}

	Scip* scip = 0;
	SCIP_CALL(SCIPcreate(&scip));
	SCIP_CALL(SCIPincludeDefaultPlugins(scip));

	// disable scip output to stdout
	SCIPmessagehdlrSetQuiet(SCIPgetMessagehdlr(scip), TRUE);

	SCIP_CALL(SCIPreadProb(scip, file_name.c_str(), 0));

	// SCIPgetProbName() returns the original file name
	name_ = details::base_name(SCIPgetProbName(scip));
	LinearObjective::Sense s = SCIPgetObjsense(scip) == SCIP_OBJSENSE_MINIMIZE ? LinearObjective::MINIMIZE : LinearObjective::MAXIMIZE;
	objective_->set_sense(s);

	const double infinity = Bound::infinity();

	// create variables
	int num_var = SCIPgetNVars(scip);
	SCIP_VAR** scip_variables = SCIPgetVars(scip);
	const std::vector<Variable*>& variables = create_n_variables(num_var);
	for (std::size_t i = 0; i < num_var; ++i) {
		SCIP_VAR* v = scip_variables[i];
		const std::size_t idx = SCIPvarGetIndex(v);
		Variable* var = variables[idx];

		const char* name = SCIPvarGetName(v);
		var->set_name(name);

		double lb = SCIPvarGetLbGlobal(v);
		double ub = SCIPvarGetUbGlobal(v);
		var->set_bounds(lb, ub);

		switch (SCIPvarGetType(v))
		{
		case SCIP_VARTYPE_BINARY:
			var->set_variable_type(Variable::BINARY);
			break;
		case SCIP_VARTYPE_INTEGER:
			var->set_variable_type(Variable::INTEGER);
			break;
		case SCIP_VARTYPE_CONTINUOUS:
		default:
			var->set_variable_type(Variable::CONTINUOUS);
			break;