Exemple #1
0
def _map_variable_stages(model):

    variable_stage_annotation = locate_annotations(model,
                                                   VariableStageAnnotation,
                                                   max_allowed=1)
    if len(variable_stage_annotation) == 0:
        raise ValueError("Reference model is missing variable stage "
                         "annotation: %s" % (VariableStageAnnotation.__name__))
    else:
        assert len(variable_stage_annotation) == 1
        variable_stage_annotation = variable_stage_annotation[0][1]

    variable_stage_assignments = ComponentMap(
        variable_stage_annotation.expand_entries())
    if len(variable_stage_assignments) == 0:
        raise ValueError("At least one variable stage assignment "
                         "is required.")

    min_stagenumber = min(variable_stage_assignments.values(),
                          key=lambda x: x[0])[0]
    max_stagenumber = max(variable_stage_assignments.values(),
                          key=lambda x: x[0])[0]
    if max_stagenumber > 2:
        for var, (stagenum, derived) in \
              variable_stage_assignments.items():
            if stagenum > 2:
                raise ValueError(
                    "Embedded stochastic programs must be two-stage "
                    "(for now), but variable with name '%s' has been "
                    "annotated with stage number: %s" % (var.name, stagenum))

    stage_to_variables_map = {}
    stage_to_variables_map[1] = []
    stage_to_variables_map[2] = []
    for var in model.component_data_objects(
            Var,
            active=True,
            descend_into=True,
            sort=SortComponents.alphabetizeComponentAndIndex):
        stagenumber, derived = \
            variable_stage_assignments.get(var, (2, False))
        if (stagenumber != 1) and (stagenumber != 2):
            raise ValueError("Invalid stage annotation for variable with "
                             "name '%s'. Stage assignment must be 1 or 2. "
                             "Current value: %s" % (var.name, stagenumber))
        if (stagenumber == 1):
            stage_to_variables_map[1].append((var, derived))
        else:
            assert stagenumber == 2
            stage_to_variables_map[2].append((var, derived))

    variable_to_stage_map = ComponentMap()
    for stagenum, stagevars in stage_to_variables_map.items():
        for var, derived in stagevars:
            variable_to_stage_map[var] = (stagenum, derived)

    return (stage_to_variables_map, variable_to_stage_map,
            variable_stage_assignments)
Exemple #2
0
    def test_perfect_matching(self):
        model = make_gas_expansion_model()

        # These are the variables and constraints of the square,
        # nonsingular subsystem
        variables = []
        variables.extend(model.P.values())
        variables.extend(model.T[i] for i in model.streams
                         if i != model.streams.first())
        variables.extend(model.rho[i] for i in model.streams
                         if i != model.streams.first())
        variables.extend(model.F[i] for i in model.streams
                         if i != model.streams.first())

        constraints = list(model.component_data_objects(pyo.Constraint))

        imat = get_structural_incidence_matrix(variables, constraints)
        con_idx_map = ComponentMap((c, i) for i, c in enumerate(constraints))

        n_var = len(variables)
        matching = maximum_matching(imat)
        matching = ComponentMap(
            (c, variables[matching[con_idx_map[c]]]) for c in constraints)
        values = ComponentSet(matching.values())
        self.assertEqual(len(matching), n_var)
        self.assertEqual(len(values), n_var)

        # The subset of variables and equations we have identified
        # do not have a unique perfect matching. But we at least know
        # this much.
        self.assertIs(matching[model.ideal_gas[0]], model.P[0])
Exemple #3
0
    def test_triangularize(self):
        N = 5
        model = make_gas_expansion_model(N)

        # These are the variables and constraints of the square,
        # nonsingular subsystem
        variables = []
        variables.extend(model.P.values())
        variables.extend(model.T[i] for i in model.streams
                         if i != model.streams.first())
        variables.extend(model.rho[i] for i in model.streams
                         if i != model.streams.first())
        variables.extend(model.F[i] for i in model.streams
                         if i != model.streams.first())

        constraints = list(model.component_data_objects(pyo.Constraint))

        imat = get_structural_incidence_matrix(variables, constraints)
        con_idx_map = ComponentMap((c, i) for i, c in enumerate(constraints))
        var_idx_map = ComponentMap((v, i) for i, v in enumerate(variables))

        row_block_map, col_block_map = block_triangularize(imat)
        var_block_map = ComponentMap(
            (v, col_block_map[var_idx_map[v]]) for v in variables)
        con_block_map = ComponentMap(
            (c, row_block_map[con_idx_map[c]]) for c in constraints)

        var_values = set(var_block_map.values())
        con_values = set(con_block_map.values())
        self.assertEqual(len(var_values), N + 1)
        self.assertEqual(len(con_values), N + 1)

        self.assertEqual(var_block_map[model.P[0]], 0)

        for i in model.streams:
            if i != model.streams.first():
                self.assertEqual(var_block_map[model.rho[i]], i)
                self.assertEqual(var_block_map[model.T[i]], i)
                self.assertEqual(var_block_map[model.P[i]], i)
                self.assertEqual(var_block_map[model.F[i]], i)

                self.assertEqual(con_block_map[model.ideal_gas[i]], i)
                self.assertEqual(con_block_map[model.expansion[i]], i)
                self.assertEqual(con_block_map[model.mbal[i]], i)
                self.assertEqual(con_block_map[model.ebal[i]], i)
def solve_separation_problem(model_data, config):

    # Timing variables
    global_solve_time = 0
    local_solve_time = 0

    # List of objective functions
    objectives_map = model_data.separation_model.util.map_obj_to_constr
    constraint_map_to_master = model_data.separation_model.util.map_new_constraint_list_to_original_con

    # Add additional or remaining separation objectives to the dict
    # (those either not assigned an explicit priority or those added by Pyros for ssv bounds)
    config_sep_priority_dict = config.separation_priority_order
    actual_sep_priority_dict = ComponentMap()
    for perf_con in model_data.separation_model.util.performance_constraints:
        actual_sep_priority_dict[perf_con] = config_sep_priority_dict.get(
            perf_con.name, 0)

    # "Bin" the objectives based on priorities
    sorted_unique_priorities = sorted(list(
        set(actual_sep_priority_dict.values())),
                                      reverse=True)
    set_of_deterministic_constraints = model_data.separation_model.util.deterministic_constraints
    if hasattr(model_data.separation_model, "epigraph_constr"):
        set_of_deterministic_constraints.add(
            model_data.separation_model.epigraph_constr)
    for is_global in (False, True):
        solver = config.global_solver if \
            (is_global or config.bypass_local_separation) else config.local_solver
        solve_data_list = []

        for val in sorted_unique_priorities:
            # Descending ordered by value
            # The list of performance constraints with this priority
            perf_constraints = [
                constr_name
                for constr_name, priority in actual_sep_priority_dict.items()
                if priority == val
            ]
            for perf_con in perf_constraints:
                #config.progress_logger.info("Separating constraint " + str(perf_con))
                try:
                    separation_obj = objectives_map[perf_con]
                except:
                    raise ValueError(
                        "Error in mapping separation objective to its master constraint form."
                    )
                separation_obj.activate()

                if perf_con in set_of_deterministic_constraints:
                    nom_constraint = perf_con
                else:
                    nom_constraint = constraint_map_to_master[perf_con]

                try:
                    model_data.master_nominal_scenario_value = value(
                        model_data.master_nominal_scenario.find_component(
                            nom_constraint))
                except:
                    raise ValueError(
                        "Unable to access nominal scenario value for the constraint "
                        + str(nom_constraint))

                if config.uncertainty_set.geometry == Geometry.DISCRETE_SCENARIOS:
                    solve_data_list.append(
                        discrete_solve(model_data=model_data,
                                       config=config,
                                       solver=solver,
                                       is_global=is_global))
                    if all(s.termination_condition in globally_acceptable for
                           sep_soln_list in solve_data_list for s in sep_soln_list) or \
                            (is_global == False and all(s.termination_condition in locally_acceptable for
                                                        sep_soln_list in solve_data_list for s in sep_soln_list)):
                        exit_separation_loop = False
                    else:
                        exit_separation_loop = True
                else:
                    solve_data = SeparationResult()
                    exit_separation_loop = solver_call_separation(
                        model_data=model_data,
                        config=config,
                        solver=solver,
                        solve_data=solve_data,
                        is_global=is_global)
                    solve_data_list.append([solve_data])

                # === Keep track of total solve times
                if is_global or config.bypass_local_separation:
                    if config.uncertainty_set.geometry == Geometry.DISCRETE_SCENARIOS:
                        for sublist in solve_data_list:
                            for s in sublist:
                                global_solve_time += get_time_from_solver(
                                    s.results)
                    else:
                        global_solve_time += get_time_from_solver(
                            solve_data.results)
                else:
                    if config.uncertainty_set.geometry == Geometry.DISCRETE_SCENARIOS:
                        for sublist in solve_data_list:
                            for s in sublist:
                                local_solve_time += get_time_from_solver(
                                    s.results)
                    else:
                        local_solve_time += get_time_from_solver(
                            solve_data.results)

                # === Terminate for timing
                if exit_separation_loop:
                    return solve_data_list, [], [], is_global, local_solve_time, global_solve_time
                separation_obj.deactivate()

        # Do we return?
        # If their are multiple violations in this bucket, pick the worst-case
        idx_i, idx_j = get_index_of_max_violation(
            model_data=model_data,
            config=config,
            solve_data_list=solve_data_list)

        violating_realizations = [
            v
            for v in solve_data_list[idx_i][idx_j].violating_param_realization
        ]
        violations = solve_data_list[idx_i][idx_j].list_of_scaled_violations

        if any(s.found_violation for solve_list in solve_data_list
               for s in solve_list):
            #config.progress_logger.info(
            #	"Violation found in constraint %s with realization %s" % (
            #	list(objectives_map.keys())[idx_i], violating_realizations))
            return solve_data_list, violating_realizations, violations, is_global, local_solve_time, global_solve_time

    return solve_data_list, [], [], is_global, local_solve_time, global_solve_time
Exemple #5
0
class GurobiDirect(DirectSolver):

    _verified_license = None

    def __init__(self, **kwds):
        if 'type' not in kwds:
            kwds['type'] = 'gurobi_direct'
        super(GurobiDirect, self).__init__(**kwds)
        self._pyomo_var_to_solver_var_map = ComponentMap()
        self._solver_var_to_pyomo_var_map = ComponentMap()
        self._pyomo_con_to_solver_con_map = dict()
        self._solver_con_to_pyomo_con_map = ComponentMap()
        self._needs_updated = True  # flag that indicates if solver_model.update() needs called before getting variable and constraint attributes
        self._callback = None
        self._callback_func = None

        self._name = None
        try:
            import gurobipy
            self._gurobipy = gurobipy
            self._python_api_exists = True
            self._version = self._gurobipy.gurobi.version()
            self._name = "Gurobi %s.%s%s" % self._version
            while len(self._version) < 4:
                self._version += (0, )
            self._version = self._version[:4]
            self._version_major = self._version[0]
        except ImportError:
            self._python_api_exists = False
        except Exception as e:
            # other forms of exceptions can be thrown by the gurobi python
            # import. for example, a gurobipy.GurobiError exception is thrown
            # if all tokens for Gurobi are already in use. assuming, of
            # course, the license is a token license. unfortunately, you can't
            # import without a license, which means we can't test for the
            # exception above!
            logger.error("Import of gurobipy failed - gurobi message=%s\n" %
                         (e, ))
            self._python_api_exists = False

        self._range_constraints = set()

        self._max_obj_degree = 2
        self._max_constraint_degree = 2

        # Note: Undefined capabilites default to None
        self._capabilities.linear = True
        self._capabilities.quadratic_objective = True
        self._capabilities.quadratic_constraint = True
        self._capabilities.integer = True
        self._capabilities.sos1 = True
        self._capabilities.sos2 = True

        # fix for compatibility with pre-5.0 Gurobi
        if self._python_api_exists and \
           (self._version_major < 5):
            self._max_constraint_degree = 1
            self._capabilities.quadratic_constraint = False

    def available(self, exception_flag=True):
        if not super().available(exception_flag):
            return False
        if self._verified_license is None:
            try:
                # verify that we can get a Gurobi license
                m = self._gurobipy.Model()
                m.dispose()
                GurobiDirect._verified_license = True
            except Exception as e:
                logger.error("Could not create Model - gurobi message=%s\n" %
                             (e, ))
                GurobiDirect._verified_license = False
        return self._verified_license

    def _apply_solver(self):
        if not self._save_results:
            for block in self._pyomo_model.block_data_objects(
                    descend_into=True, active=True):
                for var in block.component_data_objects(
                        ctype=pyomo.core.base.var.Var,
                        descend_into=False,
                        active=True,
                        sort=False):
                    var.stale = True
        if self._tee:
            self._solver_model.setParam('OutputFlag', 1)
        else:
            self._solver_model.setParam('OutputFlag', 0)

        self._solver_model.setParam('LogFile', self._log_file)

        if self._keepfiles:
            print("Solver log file: " + self._log_file)

        # Options accepted by gurobi (case insensitive):
        # ['Cutoff', 'IterationLimit', 'NodeLimit', 'SolutionLimit', 'TimeLimit',
        #  'FeasibilityTol', 'IntFeasTol', 'MarkowitzTol', 'MIPGap', 'MIPGapAbs',
        #  'OptimalityTol', 'PSDTol', 'Method', 'PerturbValue', 'ObjScale', 'ScaleFlag',
        #  'SimplexPricing', 'Quad', 'NormAdjust', 'BarIterLimit', 'BarConvTol',
        #  'BarCorrectors', 'BarOrder', 'Crossover', 'CrossoverBasis', 'BranchDir',
        #  'Heuristics', 'MinRelNodes', 'MIPFocus', 'NodefileStart', 'NodefileDir',
        #  'NodeMethod', 'PumpPasses', 'RINS', 'SolutionNumber', 'SubMIPNodes', 'Symmetry',
        #  'VarBranch', 'Cuts', 'CutPasses', 'CliqueCuts', 'CoverCuts', 'CutAggPasses',
        #  'FlowCoverCuts', 'FlowPathCuts', 'GomoryPasses', 'GUBCoverCuts', 'ImpliedCuts',
        #  'MIPSepCuts', 'MIRCuts', 'NetworkCuts', 'SubMIPCuts', 'ZeroHalfCuts', 'ModKCuts',
        #  'Aggregate', 'AggFill', 'PreDual', 'DisplayInterval', 'IISMethod', 'InfUnbdInfo',
        #  'LogFile', 'PreCrush', 'PreDepRow', 'PreMIQPMethod', 'PrePasses', 'Presolve',
        #  'ResultFile', 'ImproveStartTime', 'ImproveStartGap', 'Threads', 'Dummy', 'OutputFlag']
        for key, option in self.options.items():
            # When options come from the pyomo command, all
            # values are string types, so we try to cast
            # them to a numeric value in the event that
            # setting the parameter fails.
            try:
                self._solver_model.setParam(key, option)
            except TypeError:
                # we place the exception handling for
                # checking the cast of option to a float in
                # another function so that we can simply
                # call raise here instead of except
                # TypeError as e / raise e, because the
                # latter does not preserve the Gurobi stack
                # trace
                if not _is_numeric(option):
                    raise
                self._solver_model.setParam(key, float(option))

        if self._version_major >= 5:
            for suffix in self._suffixes:
                if re.match(suffix, "dual"):
                    self._solver_model.setParam(
                        self._gurobipy.GRB.Param.QCPDual, 1)

        self._solver_model.optimize(self._callback)
        self._needs_updated = False

        self._solver_model.setParam('LogFile', 'default')

        # FIXME: can we get a return code indicating if Gurobi had a significant failure?
        return Bunch(rc=None, log=None)

    def _get_expr_from_pyomo_repn(self, repn, max_degree=2):
        referenced_vars = ComponentSet()

        degree = repn.polynomial_degree()
        if (degree is None) or (degree > max_degree):
            raise DegreeError(
                'GurobiDirect does not support expressions of degree {0}.'.
                format(degree))

        if len(repn.linear_vars) > 0:
            referenced_vars.update(repn.linear_vars)
            new_expr = self._gurobipy.LinExpr(repn.linear_coefs, [
                self._pyomo_var_to_solver_var_map[i] for i in repn.linear_vars
            ])
        else:
            new_expr = 0.0

        for i, v in enumerate(repn.quadratic_vars):
            x, y = v
            new_expr += repn.quadratic_coefs[
                i] * self._pyomo_var_to_solver_var_map[
                    x] * self._pyomo_var_to_solver_var_map[y]
            referenced_vars.add(x)
            referenced_vars.add(y)

        new_expr += repn.constant

        return new_expr, referenced_vars

    def _get_expr_from_pyomo_expr(self, expr, max_degree=2):
        if max_degree == 2:
            repn = generate_standard_repn(expr, quadratic=True)
        else:
            repn = generate_standard_repn(expr, quadratic=False)

        try:
            gurobi_expr, referenced_vars = self._get_expr_from_pyomo_repn(
                repn, max_degree)
        except DegreeError as e:
            msg = e.args[0]
            msg += '\nexpr: {0}'.format(expr)
            raise DegreeError(msg)

        return gurobi_expr, referenced_vars

    def _gurobi_lb_ub_from_var(self, var):
        if var.is_fixed():
            val = var.value
            return val, val
        if var.has_lb():
            lb = value(var.lb)
        else:
            lb = -self._gurobipy.GRB.INFINITY
        if var.has_ub():
            ub = value(var.ub)
        else:
            ub = self._gurobipy.GRB.INFINITY
        return lb, ub

    def _add_var(self, var):
        varname = self._symbol_map.getSymbol(var, self._labeler)
        vtype = self._gurobi_vtype_from_var(var)
        lb, ub = self._gurobi_lb_ub_from_var(var)

        gurobipy_var = self._solver_model.addVar(lb=lb,
                                                 ub=ub,
                                                 vtype=vtype,
                                                 name=varname)

        self._pyomo_var_to_solver_var_map[var] = gurobipy_var
        self._solver_var_to_pyomo_var_map[gurobipy_var] = var
        self._referenced_variables[var] = 0

        self._needs_updated = True

    def _set_instance(self, model, kwds={}):
        self._range_constraints = set()
        DirectOrPersistentSolver._set_instance(self, model, kwds)
        self._pyomo_con_to_solver_con_map = dict()
        self._solver_con_to_pyomo_con_map = ComponentMap()
        self._pyomo_var_to_solver_var_map = ComponentMap()
        self._solver_var_to_pyomo_var_map = ComponentMap()
        try:
            if model.name is not None:
                self._solver_model = self._gurobipy.Model(model.name)
            else:
                self._solver_model = self._gurobipy.Model()
        except Exception:
            e = sys.exc_info()[1]
            msg = ("Unable to create Gurobi model. "
                   "Have you installed the Python "
                   "bindings for Gurobi?\n\n\t" +
                   "Error message: {0}".format(e))
            raise Exception(msg)

        self._add_block(model)

        for var, n_ref in self._referenced_variables.items():
            if n_ref != 0:
                if var.fixed:
                    if not self._output_fixed_variable_bounds:
                        raise ValueError(
                            "Encountered a fixed variable (%s) inside "
                            "an active objective or constraint "
                            "expression on model %s, which is usually "
                            "indicative of a preprocessing error. Use "
                            "the IO-option 'output_fixed_variable_bounds=True' "
                            "to suppress this error and fix the variable "
                            "by overwriting its bounds in the Gurobi instance."
                            % (
                                var.name,
                                self._pyomo_model.name,
                            ))

    def _add_block(self, block):
        DirectOrPersistentSolver._add_block(self, block)

    def _add_constraint(self, con):
        if not con.active:
            return None

        if is_fixed(con.body):
            if self._skip_trivial_constraints:
                return None

        conname = self._symbol_map.getSymbol(con, self._labeler)

        if con._linear_canonical_form:
            gurobi_expr, referenced_vars = self._get_expr_from_pyomo_repn(
                con.canonical_form(), self._max_constraint_degree)
        #elif isinstance(con, LinearCanonicalRepn):
        #    gurobi_expr, referenced_vars = self._get_expr_from_pyomo_repn(
        #        con,
        #        self._max_constraint_degree)
        else:
            gurobi_expr, referenced_vars = self._get_expr_from_pyomo_expr(
                con.body, self._max_constraint_degree)

        if con.has_lb():
            if not is_fixed(con.lower):
                raise ValueError("Lower bound of constraint {0} "
                                 "is not constant.".format(con))
        if con.has_ub():
            if not is_fixed(con.upper):
                raise ValueError("Upper bound of constraint {0} "
                                 "is not constant.".format(con))

        if con.equality:
            gurobipy_con = self._solver_model.addConstr(
                lhs=gurobi_expr,
                sense=self._gurobipy.GRB.EQUAL,
                rhs=value(con.lower),
                name=conname)
        elif con.has_lb() and con.has_ub():
            gurobipy_con = self._solver_model.addRange(gurobi_expr,
                                                       value(con.lower),
                                                       value(con.upper),
                                                       name=conname)
            self._range_constraints.add(con)
        elif con.has_lb():
            gurobipy_con = self._solver_model.addConstr(
                lhs=gurobi_expr,
                sense=self._gurobipy.GRB.GREATER_EQUAL,
                rhs=value(con.lower),
                name=conname)
        elif con.has_ub():
            gurobipy_con = self._solver_model.addConstr(
                lhs=gurobi_expr,
                sense=self._gurobipy.GRB.LESS_EQUAL,
                rhs=value(con.upper),
                name=conname)
        else:
            raise ValueError("Constraint does not have a lower "
                             "or an upper bound: {0} \n".format(con))

        for var in referenced_vars:
            self._referenced_variables[var] += 1
        self._vars_referenced_by_con[con] = referenced_vars
        self._pyomo_con_to_solver_con_map[con] = gurobipy_con
        self._solver_con_to_pyomo_con_map[gurobipy_con] = con

        self._needs_updated = True

    def _add_sos_constraint(self, con):
        if not con.active:
            return None

        conname = self._symbol_map.getSymbol(con, self._labeler)
        level = con.level
        if level == 1:
            sos_type = self._gurobipy.GRB.SOS_TYPE1
        elif level == 2:
            sos_type = self._gurobipy.GRB.SOS_TYPE2
        else:
            raise ValueError("Solver does not support SOS "
                             "level {0} constraints".format(level))

        gurobi_vars = []
        weights = []

        self._vars_referenced_by_con[con] = ComponentSet()

        if hasattr(con, 'get_items'):
            # aml sos constraint
            sos_items = list(con.get_items())
        else:
            # kernel sos constraint
            sos_items = list(con.items())

        for v, w in sos_items:
            self._vars_referenced_by_con[con].add(v)
            gurobi_vars.append(self._pyomo_var_to_solver_var_map[v])
            self._referenced_variables[v] += 1
            weights.append(w)

        gurobipy_con = self._solver_model.addSOS(sos_type, gurobi_vars,
                                                 weights)
        self._pyomo_con_to_solver_con_map[con] = gurobipy_con
        self._solver_con_to_pyomo_con_map[gurobipy_con] = con

        self._needs_updated = True

    def _gurobi_vtype_from_var(self, var):
        """
        This function takes a pyomo variable and returns the appropriate gurobi variable type
        :param var: pyomo.core.base.var.Var
        :return: gurobipy.GRB.CONTINUOUS or gurobipy.GRB.BINARY or gurobipy.GRB.INTEGER
        """
        if var.is_binary():
            vtype = self._gurobipy.GRB.BINARY
        elif var.is_integer():
            vtype = self._gurobipy.GRB.INTEGER
        elif var.is_continuous():
            vtype = self._gurobipy.GRB.CONTINUOUS
        else:
            raise ValueError(
                'Variable domain type is not recognized for {0}'.format(
                    var.domain))
        return vtype

    def _set_objective(self, obj):
        if self._objective is not None:
            for var in self._vars_referenced_by_obj:
                self._referenced_variables[var] -= 1
            self._vars_referenced_by_obj = ComponentSet()
            self._objective = None

        if obj.active is False:
            raise ValueError('Cannot add inactive objective to solver.')

        if obj.sense == minimize:
            sense = self._gurobipy.GRB.MINIMIZE
        elif obj.sense == maximize:
            sense = self._gurobipy.GRB.MAXIMIZE
        else:
            raise ValueError('Objective sense is not recognized: {0}'.format(
                obj.sense))

        gurobi_expr, referenced_vars = self._get_expr_from_pyomo_expr(
            obj.expr, self._max_obj_degree)

        for var in referenced_vars:
            self._referenced_variables[var] += 1

        self._solver_model.setObjective(gurobi_expr, sense=sense)
        self._objective = obj
        self._vars_referenced_by_obj = referenced_vars

        self._needs_updated = True

    def _postsolve(self):
        # the only suffixes that we extract from GUROBI are
        # constraint duals, constraint slacks, and variable
        # reduced-costs. scan through the solver suffix list
        # and throw an exception if the user has specified
        # any others.
        extract_duals = False
        extract_slacks = False
        extract_reduced_costs = False
        for suffix in self._suffixes:
            flag = False
            if re.match(suffix, "dual"):
                extract_duals = True
                flag = True
            if re.match(suffix, "slack"):
                extract_slacks = True
                flag = True
            if re.match(suffix, "rc"):
                extract_reduced_costs = True
                flag = True
            if not flag:
                raise RuntimeError(
                    "***The gurobi_direct solver plugin cannot extract solution suffix="
                    + suffix)

        gprob = self._solver_model
        grb = self._gurobipy.GRB
        status = gprob.Status

        if gprob.getAttr(self._gurobipy.GRB.Attr.IsMIP):
            if extract_reduced_costs:
                logger.warning("Cannot get reduced costs for MIP.")
            if extract_duals:
                logger.warning("Cannot get duals for MIP.")
            extract_reduced_costs = False
            extract_duals = False

        self.results = SolverResults()
        soln = Solution()

        self.results.solver.name = self._name
        self.results.solver.wallclock_time = gprob.Runtime

        if status == grb.LOADED:  # problem is loaded, but no solution
            self.results.solver.status = SolverStatus.aborted
            self.results.solver.termination_message = "Model is loaded, but no solution information is available."
            self.results.solver.termination_condition = TerminationCondition.error
            soln.status = SolutionStatus.unknown
        elif status == grb.OPTIMAL:  # optimal
            self.results.solver.status = SolverStatus.ok
            self.results.solver.termination_message = "Model was solved to optimality (subject to tolerances), " \
                                                      "and an optimal solution is available."
            self.results.solver.termination_condition = TerminationCondition.optimal
            soln.status = SolutionStatus.optimal
        elif status == grb.INFEASIBLE:
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message = "Model was proven to be infeasible"
            self.results.solver.termination_condition = TerminationCondition.infeasible
            soln.status = SolutionStatus.infeasible
        elif status == grb.INF_OR_UNBD:
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message = "Problem proven to be infeasible or unbounded."
            self.results.solver.termination_condition = TerminationCondition.infeasibleOrUnbounded
            soln.status = SolutionStatus.unsure
        elif status == grb.UNBOUNDED:
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message = "Model was proven to be unbounded."
            self.results.solver.termination_condition = TerminationCondition.unbounded
            soln.status = SolutionStatus.unbounded
        elif status == grb.CUTOFF:
            self.results.solver.status = SolverStatus.aborted
            self.results.solver.termination_message = "Optimal objective for model was proven to be worse than the " \
                                                      "value specified in the Cutoff parameter. No solution " \
                                                      "information is available."
            self.results.solver.termination_condition = TerminationCondition.minFunctionValue
            soln.status = SolutionStatus.unknown
        elif status == grb.ITERATION_LIMIT:
            self.results.solver.status = SolverStatus.aborted
            self.results.solver.termination_message = "Optimization terminated because the total number of simplex " \
                                                      "iterations performed exceeded the value specified in the " \
                                                      "IterationLimit parameter."
            self.results.solver.termination_condition = TerminationCondition.maxIterations
            soln.status = SolutionStatus.stoppedByLimit
        elif status == grb.NODE_LIMIT:
            self.results.solver.status = SolverStatus.aborted
            self.results.solver.termination_message = "Optimization terminated because the total number of " \
                                                      "branch-and-cut nodes explored exceeded the value specified " \
                                                      "in the NodeLimit parameter"
            self.results.solver.termination_condition = TerminationCondition.maxEvaluations
            soln.status = SolutionStatus.stoppedByLimit
        elif status == grb.TIME_LIMIT:
            self.results.solver.status = SolverStatus.aborted
            self.results.solver.termination_message = "Optimization terminated because the time expended exceeded " \
                                                      "the value specified in the TimeLimit parameter."
            self.results.solver.termination_condition = TerminationCondition.maxTimeLimit
            soln.status = SolutionStatus.stoppedByLimit
        elif status == grb.SOLUTION_LIMIT:
            self.results.solver.status = SolverStatus.aborted
            self.results.solver.termination_message = "Optimization terminated because the number of solutions found " \
                                                      "reached the value specified in the SolutionLimit parameter."
            self.results.solver.termination_condition = TerminationCondition.unknown
            soln.status = SolutionStatus.stoppedByLimit
        elif status == grb.INTERRUPTED:
            self.results.solver.status = SolverStatus.aborted
            self.results.solver.termination_message = "Optimization was terminated by the user."
            self.results.solver.termination_condition = TerminationCondition.error
            soln.status = SolutionStatus.error
        elif status == grb.NUMERIC:
            self.results.solver.status = SolverStatus.error
            self.results.solver.termination_message = "Optimization was terminated due to unrecoverable numerical " \
                                                      "difficulties."
            self.results.solver.termination_condition = TerminationCondition.error
            soln.status = SolutionStatus.error
        elif status == grb.SUBOPTIMAL:
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message = "Unable to satisfy optimality tolerances; a sub-optimal " \
                                                      "solution is available."
            self.results.solver.termination_condition = TerminationCondition.other
            soln.status = SolutionStatus.feasible
        # note that USER_OBJ_LIMIT was added in Gurobi 7.0, so it may not be present
        elif (status is not None) and \
             (status == getattr(grb,'USER_OBJ_LIMIT',None)):
            self.results.solver.status = SolverStatus.aborted
            self.results.solver.termination_message = "User specified an objective limit " \
                                                      "(a bound on either the best objective " \
                                                      "or the best bound), and that limit has " \
                                                      "been reached. Solution is available."
            self.results.solver.termination_condition = TerminationCondition.other
            soln.status = SolutionStatus.stoppedByLimit
        else:
            self.results.solver.status = SolverStatus.error
            self.results.solver.termination_message = \
                ("Unhandled Gurobi solve status "
                 "("+str(status)+")")
            self.results.solver.termination_condition = TerminationCondition.error
            soln.status = SolutionStatus.error

        self.results.problem.name = gprob.ModelName

        if gprob.ModelSense == 1:
            self.results.problem.sense = minimize
        elif gprob.ModelSense == -1:
            self.results.problem.sense = maximize
        else:
            raise RuntimeError(
                'Unrecognized gurobi objective sense: {0}'.format(
                    gprob.ModelSense))

        self.results.problem.upper_bound = None
        self.results.problem.lower_bound = None
        if (gprob.NumBinVars + gprob.NumIntVars) == 0:
            try:
                self.results.problem.upper_bound = gprob.ObjVal
                self.results.problem.lower_bound = gprob.ObjVal
            except (self._gurobipy.GurobiError, AttributeError):
                pass
        elif gprob.ModelSense == 1:  # minimizing
            try:
                self.results.problem.upper_bound = gprob.ObjVal
            except (self._gurobipy.GurobiError, AttributeError):
                pass
            try:
                self.results.problem.lower_bound = gprob.ObjBound
            except (self._gurobipy.GurobiError, AttributeError):
                pass
        elif gprob.ModelSense == -1:  # maximizing
            try:
                self.results.problem.upper_bound = gprob.ObjBound
            except (self._gurobipy.GurobiError, AttributeError):
                pass
            try:
                self.results.problem.lower_bound = gprob.ObjVal
            except (self._gurobipy.GurobiError, AttributeError):
                pass
        else:
            raise RuntimeError(
                'Unrecognized gurobi objective sense: {0}'.format(
                    gprob.ModelSense))

        try:
            soln.gap = self.results.problem.upper_bound - self.results.problem.lower_bound
        except TypeError:
            soln.gap = None

        self.results.problem.number_of_constraints = gprob.NumConstrs + gprob.NumQConstrs + gprob.NumSOS
        self.results.problem.number_of_nonzeros = gprob.NumNZs
        self.results.problem.number_of_variables = gprob.NumVars
        self.results.problem.number_of_binary_variables = gprob.NumBinVars
        self.results.problem.number_of_integer_variables = gprob.NumIntVars
        self.results.problem.number_of_continuous_variables = gprob.NumVars - gprob.NumIntVars - gprob.NumBinVars
        self.results.problem.number_of_objectives = 1
        self.results.problem.number_of_solutions = gprob.SolCount

        # if a solve was stopped by a limit, we still need to check to
        # see if there is a solution available - this may not always
        # be the case, both in LP and MIP contexts.
        if self._save_results:
            """
            This code in this if statement is only needed for backwards compatability. It is more efficient to set
            _save_results to False and use load_vars, load_duals, etc.
            """
            if gprob.SolCount > 0:
                soln_variables = soln.variable
                soln_constraints = soln.constraint

                gurobi_vars = self._solver_model.getVars()
                gurobi_vars = list(
                    set(gurobi_vars).intersection(
                        set(self._pyomo_var_to_solver_var_map.values())))
                var_vals = self._solver_model.getAttr("X", gurobi_vars)
                names = self._solver_model.getAttr("VarName", gurobi_vars)
                for gurobi_var, val, name in zip(gurobi_vars, var_vals, names):
                    pyomo_var = self._solver_var_to_pyomo_var_map[gurobi_var]
                    if self._referenced_variables[pyomo_var] > 0:
                        pyomo_var.stale = False
                        soln_variables[name] = {"Value": val}

                if extract_reduced_costs:
                    vals = self._solver_model.getAttr("Rc", gurobi_vars)
                    for gurobi_var, val, name in zip(gurobi_vars, vals, names):
                        pyomo_var = self._solver_var_to_pyomo_var_map[
                            gurobi_var]
                        if self._referenced_variables[pyomo_var] > 0:
                            soln_variables[name]["Rc"] = val

                if extract_duals or extract_slacks:
                    gurobi_cons = self._solver_model.getConstrs()
                    con_names = self._solver_model.getAttr(
                        "ConstrName", gurobi_cons)
                    for name in con_names:
                        soln_constraints[name] = {}
                    if self._version_major >= 5:
                        gurobi_q_cons = self._solver_model.getQConstrs()
                        q_con_names = self._solver_model.getAttr(
                            "QCName", gurobi_q_cons)
                        for name in q_con_names:
                            soln_constraints[name] = {}

                if extract_duals:
                    vals = self._solver_model.getAttr("Pi", gurobi_cons)
                    for val, name in zip(vals, con_names):
                        soln_constraints[name]["Dual"] = val
                    if self._version_major >= 5:
                        q_vals = self._solver_model.getAttr(
                            "QCPi", gurobi_q_cons)
                        for val, name in zip(q_vals, q_con_names):
                            soln_constraints[name]["Dual"] = val

                if extract_slacks:
                    gurobi_range_con_vars = set(
                        self._solver_model.getVars()) - set(
                            self._pyomo_var_to_solver_var_map.values())
                    vals = self._solver_model.getAttr("Slack", gurobi_cons)
                    for gurobi_con, val, name in zip(gurobi_cons, vals,
                                                     con_names):
                        pyomo_con = self._solver_con_to_pyomo_con_map[
                            gurobi_con]
                        if pyomo_con in self._range_constraints:
                            lin_expr = self._solver_model.getRow(gurobi_con)
                            for i in reversed(range(lin_expr.size())):
                                v = lin_expr.getVar(i)
                                if v in gurobi_range_con_vars:
                                    Us_ = v.X
                                    Ls_ = v.UB - v.X
                                    if Us_ > Ls_:
                                        soln_constraints[name]["Slack"] = Us_
                                    else:
                                        soln_constraints[name]["Slack"] = -Ls_
                                    break
                        else:
                            soln_constraints[name]["Slack"] = val
                    if self._version_major >= 5:
                        q_vals = self._solver_model.getAttr(
                            "QCSlack", gurobi_q_cons)
                        for val, name in zip(q_vals, q_con_names):
                            soln_constraints[name]["Slack"] = val
        elif self._load_solutions:
            if gprob.SolCount > 0:

                self._load_vars()

                if extract_reduced_costs:
                    self._load_rc()

                if extract_duals:
                    self._load_duals()

                if extract_slacks:
                    self._load_slacks()

        self.results.solution.insert(soln)

        # finally, clean any temporary files registered with the temp file
        # manager, created populated *directly* by this plugin.
        TempfileManager.pop(remove=not self._keepfiles)

        return DirectOrPersistentSolver._postsolve(self)

    def warm_start_capable(self):
        return True

    def _warm_start(self):
        for pyomo_var, gurobipy_var in self._pyomo_var_to_solver_var_map.items(
        ):
            if pyomo_var.value is not None:
                gurobipy_var.setAttr(self._gurobipy.GRB.Attr.Start,
                                     value(pyomo_var))
        self._needs_updated = True

    def _load_vars(self, vars_to_load=None):
        var_map = self._pyomo_var_to_solver_var_map
        ref_vars = self._referenced_variables
        if vars_to_load is None:
            vars_to_load = var_map.keys()

        gurobi_vars_to_load = [
            var_map[pyomo_var] for pyomo_var in vars_to_load
        ]
        vals = self._solver_model.getAttr("X", gurobi_vars_to_load)

        for var, val in zip(vars_to_load, vals):
            if ref_vars[var] > 0:
                var.stale = False
                var.value = val

    def _load_rc(self, vars_to_load=None):
        if not hasattr(self._pyomo_model, 'rc'):
            self._pyomo_model.rc = Suffix(direction=Suffix.IMPORT)
        var_map = self._pyomo_var_to_solver_var_map
        ref_vars = self._referenced_variables
        rc = self._pyomo_model.rc
        if vars_to_load is None:
            vars_to_load = var_map.keys()

        gurobi_vars_to_load = [
            var_map[pyomo_var] for pyomo_var in vars_to_load
        ]
        vals = self._solver_model.getAttr("Rc", gurobi_vars_to_load)

        for var, val in zip(vars_to_load, vals):
            if ref_vars[var] > 0:
                rc[var] = val

    def _load_duals(self, cons_to_load=None):
        if not hasattr(self._pyomo_model, 'dual'):
            self._pyomo_model.dual = Suffix(direction=Suffix.IMPORT)
        con_map = self._pyomo_con_to_solver_con_map
        reverse_con_map = self._solver_con_to_pyomo_con_map
        dual = self._pyomo_model.dual

        if cons_to_load is None:
            linear_cons_to_load = self._solver_model.getConstrs()
            if self._version_major >= 5:
                quadratic_cons_to_load = self._solver_model.getQConstrs()
        else:
            gurobi_cons_to_load = set(
                [con_map[pyomo_con] for pyomo_con in cons_to_load])
            linear_cons_to_load = gurobi_cons_to_load.intersection(
                set(self._solver_model.getConstrs()))
            if self._version_major >= 5:
                quadratic_cons_to_load = gurobi_cons_to_load.intersection(
                    set(self._solver_model.getQConstrs()))
        linear_vals = self._solver_model.getAttr("Pi", linear_cons_to_load)
        if self._version_major >= 5:
            quadratic_vals = self._solver_model.getAttr(
                "QCPi", quadratic_cons_to_load)

        for gurobi_con, val in zip(linear_cons_to_load, linear_vals):
            pyomo_con = reverse_con_map[gurobi_con]
            dual[pyomo_con] = val
        if self._version_major >= 5:
            for gurobi_con, val in zip(quadratic_cons_to_load, quadratic_vals):
                pyomo_con = reverse_con_map[gurobi_con]
                dual[pyomo_con] = val

    def _load_slacks(self, cons_to_load=None):
        if not hasattr(self._pyomo_model, 'slack'):
            self._pyomo_model.slack = Suffix(direction=Suffix.IMPORT)
        con_map = self._pyomo_con_to_solver_con_map
        reverse_con_map = self._solver_con_to_pyomo_con_map
        slack = self._pyomo_model.slack

        gurobi_range_con_vars = set(self._solver_model.getVars()) - set(
            self._pyomo_var_to_solver_var_map.values())

        if cons_to_load is None:
            linear_cons_to_load = self._solver_model.getConstrs()
            if self._version_major >= 5:
                quadratic_cons_to_load = self._solver_model.getQConstrs()
        else:
            gurobi_cons_to_load = set(
                [con_map[pyomo_con] for pyomo_con in cons_to_load])
            linear_cons_to_load = gurobi_cons_to_load.intersection(
                set(self._solver_model.getConstrs()))
            if self._version_major >= 5:
                quadratic_cons_to_load = gurobi_cons_to_load.intersection(
                    set(self._solver_model.getQConstrs()))
        linear_vals = self._solver_model.getAttr("Slack", linear_cons_to_load)
        if self._version_major >= 5:
            quadratic_vals = self._solver_model.getAttr(
                "QCSlack", quadratic_cons_to_load)

        for gurobi_con, val in zip(linear_cons_to_load, linear_vals):
            pyomo_con = reverse_con_map[gurobi_con]
            if pyomo_con in self._range_constraints:
                lin_expr = self._solver_model.getRow(gurobi_con)
                for i in reversed(range(lin_expr.size())):
                    v = lin_expr.getVar(i)
                    if v in gurobi_range_con_vars:
                        Us_ = v.X
                        Ls_ = v.UB - v.X
                        if Us_ > Ls_:
                            slack[pyomo_con] = Us_
                        else:
                            slack[pyomo_con] = -Ls_
                        break
            else:
                slack[pyomo_con] = val
        if self._version_major >= 5:
            for gurobi_con, val in zip(quadratic_cons_to_load, quadratic_vals):
                pyomo_con = reverse_con_map[gurobi_con]
                slack[pyomo_con] = val

    def load_duals(self, cons_to_load=None):
        """
        Load the duals into the 'dual' suffix. The 'dual' suffix must live on the parent model.

        Parameters
        ----------
        cons_to_load: list of Constraint
        """
        self._load_duals(cons_to_load)

    def load_rc(self, vars_to_load):
        """
        Load the reduced costs into the 'rc' suffix. The 'rc' suffix must live on the parent model.

        Parameters
        ----------
        vars_to_load: list of Var
        """
        self._load_rc(vars_to_load)

    def load_slacks(self, cons_to_load=None):
        """
        Load the values of the slack variables into the 'slack' suffix. The 'slack' suffix must live on the parent
        model.

        Parameters
        ----------
        cons_to_load: list of Constraint
        """
        self._load_slacks(cons_to_load)

    def _update(self):
        self._solver_model.update()
        self._needs_updated = False
Exemple #6
0
class MosekDirect(DirectSolver):

    def __init__(self, **kwds):
        kwds['type'] = 'mosek'
        DirectSolver.__init__(self, **kwds)
        self._pyomo_var_to_solver_var_map = ComponentMap()
        self._solver_var_to_pyomo_var_map = ComponentMap()
        self._pyomo_con_to_solver_con_map = dict()
        self._solver_con_to_pyomo_con_map = ComponentMap()
        self._pyomo_cone_to_solver_cone_map = dict()
        self._solver_cone_to_pyomo_cone_map = ComponentMap()
        self._init()

    def _init(self):
        self._name = None
        try:
            import mosek
            self._mosek = mosek
            self._mosek_env = self._mosek.Env()
            self._python_api_exists = True
            self._version = self._mosek_env.getversion()
            if self._version[0] > 8:
                self._name = "Mosek %s.%s.%s" % self._version
                while len(self._version) < 3:
                    self._version += (0,)
            else:
                self._name = "Mosek %s.%s.%s.%s" % self._version
                while len(self._version) < 4:
                    self._version += (0,)

            self._version_major = self._version[0]
        except ImportError:
            self._python_api_exists = False
        except Exception as e:
            print("Import of mosek failed - mosek message=" + str(e) + "\n")
            self._python_api_exists = False

        self._range_constraints = set()

        self._max_obj_degree = 2
        self._max_constraint_degree = 2
        self._termcode = None

        # Note: Undefined capabilites default to None
        self._capabilities.linear = True
        self._capabilities.quadratic_objective = True
        self._capabilities.quadratic_constraint = True
        self._capabilities.integer = True
        self._capabilities.sos1 = False
        self._capabilities.sos2 = False

    @staticmethod
    def license_is_valid():
        """
        Runs a check for a valid Mosek license. Returns False
        if Mosek fails to run on a trivial test case.
        """
        try:
            import mosek
        except ImportError:
            return False
        try:
            mosek.Env().Task(0,0).optimize()
        except mosek.Error:
            return False
        return True

    def _apply_solver(self):
        if not self._save_results:
            for block in self._pyomo_model.block_data_objects(descend_into=True,
                                                              active=True):
                for var in block.component_data_objects(ctype=pyomo.core.base.var.Var,
                                                        descend_into=False,
                                                        active=True,
                                                        sort=False):
                    var.stale = True
        if self._tee:
            def _process_stream(msg):
                sys.stdout.write(msg)
                sys.stdout.flush()
            self._solver_model.set_Stream(
                self._mosek.streamtype.log, _process_stream)

        if self._keepfiles:
            print("Solver log file: "+self._log_file)

        for key, option in self.options.items():

            param = self._mosek

            try:
                for sub_key in key.split('.'):
                    param = getattr(param, sub_key)
            except (TypeError, AttributeError):
                raise

            if 'sparam' in key.split('.'):
                self._solver_model.putstrparam(param, option)
            else:
                if 'iparam' in key.split('.'):
                    self._solver_model.putintparam(param, option)
                elif 'dparam' in key.split('.'):
                    self._solver_model.putdouparam(param, option)
                else:
                    raise AttributeError(
                        "Unknown parameter type. Type sparam, iparam or dparam expected.")

        self._termcode = self._solver_model.optimize()
        self._solver_model.solutionsummary(self._mosek.streamtype.msg)

        # FIXME: can we get a return code indicating if Mosek had a significant failure?
        return Bunch(rc=None, log=None)

    def _get_cone_data(self, con):
        # if the cone is not recognized, this function
        # will return None for cone_type and cone_members
        cone_type = None
        cone_param = 0
        cone_members = None
        if isinstance(con, quadratic):
            assert con.has_ub() and \
                (con.ub == 0) and (not con.has_lb())
            assert con.check_convexity_conditions(relax=True)
            cone_type = self._mosek.conetype.quad
            cone_members = [con.r] + list(con.x)
        elif isinstance(con, rotated_quadratic):
            assert con.has_ub() and \
                (con.ub == 0) and (not con.has_lb())
            assert con.check_convexity_conditions(relax=True)
            cone_type = self._mosek.conetype.rquad
            cone_members = [con.r1, con.r2] + list(con.x)
        elif self._version >= (9, 0, 0):
            if isinstance(con, primal_exponential):
                assert con.has_ub() and \
                    (con.ub == 0) and (not con.has_lb())
                assert con.check_convexity_conditions(
                    relax=False)
                cone_type = self._mosek.conetype.pexp
                cone_members = [con.r, con.x1, con.x2]
            elif isinstance(con, primal_power):
                assert con.has_ub() and \
                    (con.ub == 0) and (not con.has_lb())
                assert con.check_convexity_conditions(
                    relax=False)
                cone_type = self._mosek.conetype.ppow
                cone_param = value(con.alpha)
                cone_members = [con.r1, con.r2] + list(con.x)
            elif isinstance(con, dual_exponential):
                assert con.has_ub() and \
                    (con.ub == 0) and (not con.has_lb())
                assert con.check_convexity_conditions(
                    relax=False)
                cone_type = self._mosek.conetype.dexp
                cone_members = [con.r, con.x1, con.x2]
            elif isinstance(con, dual_power):
                assert con.has_ub() and \
                    (con.ub == 0) and (not con.has_lb())
                assert con.check_convexity_conditions(
                    relax=False)
                cone_type = self._mosek.conetype.dpow
                cone_param = value(con.alpha)
                cone_members = [con.r1, con.r2] + list(con.x)

        return cone_type, cone_param, cone_members

    def _get_expr_from_pyomo_repn(self, repn, max_degree=2):
        referenced_vars = ComponentSet()

        degree = repn.polynomial_degree()
        if (degree is None) or (degree > max_degree):
            raise DegreeError(
                'Mosek does not support expressions of degree {0}.'.format(degree))

        # if len(repn.linear_vars) > 0:
        referenced_vars.update(repn.linear_vars)

        indexes = []
        [indexes.append(self._pyomo_var_to_solver_var_map[i])
         for i in repn.linear_vars]

        new_expr = [list(repn.linear_coefs), indexes, repn.constant]

        qsubi = []
        qsubj = []
        qval = []
        for i, v in enumerate(repn.quadratic_vars):
            x, y = v
            qsubj.append(self._pyomo_var_to_solver_var_map[x])
            qsubi.append(self._pyomo_var_to_solver_var_map[y])
            qval.append(repn.quadratic_coefs[i]*((qsubi==qsubj)+1))
            referenced_vars.add(x)
            referenced_vars.add(y)
        new_expr.extend([qval, qsubi, qsubj])

        return new_expr, referenced_vars

    def _get_expr_from_pyomo_expr(self, expr, max_degree=2):
        if max_degree == 2:
            repn = generate_standard_repn(expr, quadratic=True)
        else:
            repn = generate_standard_repn(expr, quadratic=False)

        try:
            mosek_expr, referenced_vars = self._get_expr_from_pyomo_repn(
                repn, max_degree)
        except DegreeError as e:
            msg = e.args[0]
            msg += '\nexpr: {0}'.format(expr)
            raise DegreeError(msg)

        return mosek_expr, referenced_vars

    def _add_var(self, var):
        varname = self._symbol_map.getSymbol(var, self._labeler)
        vtype = self._mosek_vtype_from_var(var)
        if var.has_lb():
            lb = value(var.lb)
        else:
            lb = '0'
        if var.has_ub():
            ub = value(var.ub)
        else:
            ub = '0'

        bound_type = self.set_var_boundtype(var, ub, lb)
        self._solver_model.appendvars(1)
        index = self._solver_model.getnumvar()-1
        self._solver_model.putvarbound(index, bound_type, float(lb), float(ub))
        self._solver_model.putvartype(index, vtype)
        self._solver_model.putvarname(index, varname)

        self._pyomo_var_to_solver_var_map[var] = index
        self._solver_var_to_pyomo_var_map[index] = var
        self._referenced_variables[var] = 0

    def _set_instance(self, model, kwds={}):
        self._range_constraints = set()
        DirectOrPersistentSolver._set_instance(self, model, kwds)
        self._pyomo_con_to_solver_con_map = dict()
        self._solver_con_to_pyomo_con_map = ComponentMap()
        self._pyomo_cone_to_solver_cone_map = dict()
        self._solver_cone_to_pyomo_cone_map = ComponentMap()
        self._pyomo_var_to_solver_var_map = ComponentMap()
        self._solver_var_to_pyomo_var_map = ComponentMap()
        self._whichsol = getattr(
            self._mosek.soltype, kwds.pop('soltype', 'bas'))

        try:
            self._solver_model = self._mosek_env.Task(0, 0)
        except Exception:
            e = sys.exc_info()[1]
            msg = ("Unable to create Mosek Task. "
                   "Have you installed the Python "
                   "bindings for Mosek?\n\n\t" +
                   "Error message: {0}".format(e))
            raise Exception(msg)

        self._add_block(model)

    def _add_block(self, block):
        DirectOrPersistentSolver._add_block(self, block)

    def _add_constraint(self, con):
        if not con.active:
            return None

        if is_fixed(con.body):
            if self._skip_trivial_constraints:
                return None

        conname = self._symbol_map.getSymbol(con, self._labeler)

        mosek_expr = None
        referenced_vars = None
        cone_type = None
        cone_param = 0
        cone_members = None
        if con._linear_canonical_form:
            mosek_expr, referenced_vars = self._get_expr_from_pyomo_repn(
                con.canonical_form(),
                self._max_constraint_degree)
        elif isinstance(con, _ConicBase):
            cone_type, cone_param, cone_members = \
                self._get_cone_data(con)
            if cone_type is not None:
                assert cone_members is not None
                referenced_vars = ComponentSet(cone_members)
            else:
                logger.warning("Cone %s was not recognized by Mosek"
                               % (str(con)))
                # the cone was not recognized, treat
                # it like a standard constraint, which
                # will in all likelihood lead to Mosek
                # reporting a helpful error message
                assert mosek_expr is None
        if (mosek_expr is None) and (cone_type is None):
            mosek_expr, referenced_vars = \
                self._get_expr_from_pyomo_expr(
                    con.body,
                    self._max_constraint_degree)

        assert referenced_vars is not None
        if mosek_expr is not None:
            assert cone_type is None
            self._solver_model.appendcons(1)
            con_index = self._solver_model.getnumcon()-1
            con_type, ub, lb = self.set_con_bounds(con, mosek_expr[2])

            if con.has_lb():
                if not is_fixed(con.lower):
                    raise ValueError("Lower bound of constraint {0} "
                                     "is not constant.".format(con))
            if con.has_ub():
                if not is_fixed(con.upper):
                    raise ValueError("Upper bound of constraint {0} "
                                     "is not constant.".format(con))

            self._solver_model.putarow(con_index, mosek_expr[1], mosek_expr[0])
            self._solver_model.putqconk(
                con_index, mosek_expr[4], mosek_expr[5], mosek_expr[3])
            self._solver_model.putconbound(con_index, con_type, lb, ub)
            self._solver_model.putconname(con_index, conname)
            self._pyomo_con_to_solver_con_map[con] = con_index
            self._solver_con_to_pyomo_con_map[con_index] = con
        else:
            assert cone_type is not None
            members = [self._pyomo_var_to_solver_var_map[v_]
                       for v_ in cone_members]
            self._solver_model.appendcone(cone_type,
                                          cone_param,
                                          members)
            cone_index = self._solver_model.getnumcone()-1
            self._solver_model.putconename(cone_index, conname)
            self._pyomo_cone_to_solver_cone_map[con] = cone_index
            self._solver_cone_to_pyomo_cone_map[cone_index] = con

        for var in referenced_vars:
            self._referenced_variables[var] += 1
        self._vars_referenced_by_con[con] = referenced_vars

    def _mosek_vtype_from_var(self, var):
        """
        This function takes a pyomo variable and returns the appropriate mosek variable type
        :param var: pyomo.core.base.var.Var
        :return: mosek.variabletype.type_int or mosek.variabletype.type_cont
        """

        if var.is_integer() or var.is_binary():
            vtype = self._mosek.variabletype.type_int
        elif var.is_continuous():
            vtype = self._mosek.variabletype.type_cont
        else:
            raise ValueError(
                'Variable domain type is not recognized for {0}'.format(var.domain))
        return vtype

    def set_var_boundtype(self, var, ub, lb):

        if var.is_fixed():
            return self._mosek.boundkey.fx
        elif ub != '0' and lb != '0':
            return self._mosek.boundkey.ra
        elif ub == '0' and lb == '0':
            return self._mosek.boundkey.fr
        elif ub != '0' and lb == '0':
            return self._mosek.boundkey.up
        return self._mosek.boundkey.lo

    def set_con_bounds(self, con, constant):

        if con.equality:
            ub = value(con.upper) - constant
            lb = value(con.lower) - constant
            con_type = self._mosek.boundkey.fx
        elif con.has_lb() and con.has_ub():
            ub = value(con.upper) - constant
            lb = value(con.lower) - constant
            con_type = self._mosek.boundkey.ra
        elif con.has_lb():
            ub = 0
            lb = value(con.lower) - constant
            con_type = self._mosek.boundkey.lo
        elif con.has_ub():
            ub = value(con.upper) - constant
            lb = 0
            con_type = self._mosek.boundkey.up
        else:
            ub = 0
            lb = 0
            con_type = self._mosek.boundkey.fr
        return con_type, ub, lb

    def _set_objective(self, obj):

        if self._objective is not None:
            for var in self._vars_referenced_by_obj:
                self._referenced_variables[var] -= 1
            self._vars_referenced_by_obj = ComponentSet()
            self._objective = None

        if obj.active is False:
            raise ValueError('Cannot add inactive objective to solver.')

        if obj.sense == minimize:
            self._solver_model.putobjsense(self._mosek.objsense.minimize)
        elif obj.sense == maximize:
            self._solver_model.putobjsense(self._mosek.objsense.maximize)
        else:
            raise ValueError(
                'Objective sense is not recognized: {0}'.format(obj.sense))

        mosek_expr, referenced_vars = self._get_expr_from_pyomo_expr(
            obj.expr, self._max_obj_degree)

        for var in referenced_vars:
            self._referenced_variables[var] += 1

        for i, j in enumerate(mosek_expr[1]):
            self._solver_model.putcj(j, mosek_expr[0][i])

        self._solver_model.putqobj(mosek_expr[4], mosek_expr[5], mosek_expr[3])
        self._solver_model.putcfix(mosek_expr[2])
        self._objective = obj
        self._vars_referenced_by_obj = referenced_vars

    def _postsolve(self):

        extract_duals = False
        extract_slacks = False
        extract_reduced_costs = False
        for suffix in self._suffixes:
            flag = False
            if re.match(suffix, "dual"):
                extract_duals = True
                flag = True
            if re.match(suffix, "slack"):
                extract_slacks = True
                flag = True
            if re.match(suffix, "rc"):
                extract_reduced_costs = True
                flag = True
            if not flag:
                raise RuntimeError(
                    "***The mosek solver plugin cannot extract solution suffix="+suffix)

        msk_task = self._solver_model
        msk = self._mosek

        itr_soltypes = [msk.problemtype.qo,
                        msk.problemtype.qcqo,
                        msk.problemtype.conic]

        if (msk_task.getnumintvar() >= 1):
            self._whichsol = msk.soltype.itg
            if extract_reduced_costs:
                logger.warning("Cannot get reduced costs for MIP.")
            if extract_duals:
                logger.warning("Cannot get duals for MIP.")
            extract_reduced_costs = False
            extract_duals = False
        elif (msk_task.getprobtype() in itr_soltypes):
            self._whichsol = msk.soltype.itr

        whichsol = self._whichsol
        sol_status = msk_task.getsolsta(whichsol)
        pro_status = msk_task.getprosta(whichsol)

        self.results = SolverResults()
        soln = Solution()

        self.results.solver.name = self._name
        self.results.solver.wallclock_time = msk_task.getdouinf(
            msk.dinfitem.optimizer_time)

        SOLSTA_MAP = {
            msk.solsta.unknown: 'unknown',
            msk.solsta.optimal: 'optimal',
            msk.solsta.prim_and_dual_feas: 'pd_feas',
            msk.solsta.prim_feas: 'p_feas',
            msk.solsta.dual_feas: 'd_feas',
            msk.solsta.prim_infeas_cer: 'p_infeas',
            msk.solsta.dual_infeas_cer: 'd_infeas',
            msk.solsta.prim_illposed_cer: 'p_illposed',
            msk.solsta.dual_illposed_cer: 'd_illposed',
            msk.solsta.integer_optimal: 'optimal'
        }
        PROSTA_MAP = {
            msk.prosta.unknown: 'unknown',
            msk.prosta.prim_and_dual_feas: 'pd_feas',
            msk.prosta.prim_feas: 'p_feas',
            msk.prosta.dual_feas: 'd_feas',
            msk.prosta.prim_infeas: 'p_infeas',
            msk.prosta.dual_infeas: 'd_infeas',
            msk.prosta.prim_and_dual_infeas: 'pd_infeas',
            msk.prosta.ill_posed: 'illposed',
            msk.prosta.prim_infeas_or_unbounded: 'p_inf_unb'
        }

        if self._version_major < 9:
            SOLSTA_OLD = {
                msk.solsta.near_optimal: 'optimal',
                msk.solsta.near_integer_optimal: 'optimal',
                msk.solsta.near_prim_feas: 'p_feas',
                msk.solsta.near_dual_feas: 'd_feas',
                msk.solsta.near_prim_and_dual_feas: 'pd_feas',
                msk.solsta.near_prim_infeas_cer: 'p_infeas',
                msk.solsta.near_dual_infeas_cer: 'd_infeas'
            }
            PROSTA_OLD = {
                msk.prosta.near_prim_and_dual_feas: 'pd_feas',
                msk.prosta.near_prim_feas: 'p_feas',
                msk.prosta.near_dual_feas: 'd_feas'
            }
            SOLSTA_MAP.update(SOLSTA_OLD)
            PROSTA_MAP.update(PROSTA_OLD)

        if self._termcode == msk.rescode.ok:
            self.results.solver.status = SolverStatus.ok
            self.results.solver.termination_message = ""

        elif self._termcode == msk.rescode.trm_max_iterations:
            self.results.solver.status = SolverStatus.ok
            self.results.solver.termination_message = "Optimization terminated because the total number " \
                "iterations performed exceeded the value specified in the " \
                "IterationLimit parameter."
            self.results.solver.termination_condition = TerminationCondition.maxIterations
            soln.status = SolutionStatus.stoppedByLimit

        elif self._termcode == msk.rescode.trm_max_time:
            self.results.solver.status = SolverStatus.ok
            self.results.solver.termination_message = "Optimization terminated because the time expended exceeded " \
                "the value specified in the TimeLimit parameter."
            self.results.solver.termination_condition = TerminationCondition.maxTimeLimit
            soln.status = SolutionStatus.stoppedByLimit

        elif self._termcode == msk.rescode.trm_user_callback:
            self.results.solver.status = SolverStatus.Aborted
            self.results.solver.termination_message = "Optimization terminated because of the user callback "
            self.results.solver.termination_condition = TerminationCondition.userInterrupt
            soln.status = SolutionStatus.unknown

        elif self._termcode in [msk.rescode.trm_mio_num_relaxs,
                                msk.rescode.trm_mio_num_branches,
                                msk.rescode.trm_num_max_num_int_solutions]:
            self.results.solver.status = SolverStatus.ok
            self.results.solver.termination_message = "Optimization terminated because maximum number of relaxations" \
                " / branches / integer solutions exceeded " \
                "the value specified in the TimeLimit parameter."
            self.results.solver.termination_condition = TerminationCondition.maxEvaluations
            soln.status = SolutionStatus.stoppedByLimit

        else:
            self.results.solver.termination_message = " Optimization terminated %s response code." \
                "Check Mosek response code documentation for further explanation." % self._termcode
            self.results.solver.termination_condition = TerminationCondition.unknown

        if SOLSTA_MAP[sol_status] == 'unknown':
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message += " Unknown solution status."
            self.results.solver.Message = self.results.solver.termination_message
            self.results.solver.termination_condition = TerminationCondition.unknown
            soln.status = SolutionStatus.unknown

        if PROSTA_MAP[pro_status] == 'd_infeas':
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message += " Problem proven to be dual infeasible"
            self.results.solver.Message = self.results.solver.termination_message
            self.results.solver.termination_condition = TerminationCondition.unbounded
            soln.status = SolutionStatus.unbounded

        elif PROSTA_MAP[pro_status] == 'p_infeas':
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message += " Problem proven to be primal infeasible."
            self.results.solver.Message = self.results.solver.termination_message
            self.results.solver.termination_condition = TerminationCondition.infeasible
            soln.status = SolutionStatus.infeasible

        elif PROSTA_MAP[pro_status] == 'pd_infeas':
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message += " Problem proven to be primal and dual infeasible."
            self.results.solver.Message = self.results.solver.termination_message
            self.results.solver.termination_condition = TerminationCondition.infeasible
            soln.status = SolutionStatus.infeasible

        elif PROSTA_MAP[pro_status] == 'p_inf_unb':
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message += " Problem proven to be infeasible or unbounded."
            self.results.solver.Message = self.results.solver.termination_message
            self.results.solver.termination_condition = TerminationCondition.infeasibleOrUnbounded
            soln.status = SolutionStatus.unsure

        if SOLSTA_MAP[sol_status] == 'optimal':
            self.results.solver.status = SolverStatus.ok
            self.results.solver.termination_message += " Model was solved to optimality, " \
                "and an optimal solution is available."
            self.results.solver.termination_condition = TerminationCondition.optimal
            soln.status = SolutionStatus.optimal

        elif SOLSTA_MAP[sol_status] == 'pd_feas':
            self.results.solver.status = SolverStatus.ok
            self.results.solver.termination_message += " The solution is both primal and dual feasible"
            self.results.solver.termination_condition = TerminationCondition.feasible
            soln.status = SolutionStatus.feasible

        elif SOLSTA_MAP[sol_status] == 'p_feas':
            self.results.solver.status = SolverStatus.ok
            self.results.solver.termination_message += " Primal feasible solution is available."
            self.results.solver.termination_condition = TerminationCondition.feasible
            soln.status = SolutionStatus.feasible

        elif SOLSTA_MAP[sol_status] == 'd_feas':
            self.results.solver.status = SolverStatus.ok
            self.results.solver.termination_message += " Dual feasible solution is available."
            self.results.solver.termination_condition = TerminationCondition.feasible
            soln.status = SolutionStatus.feasible

        elif SOLSTA_MAP[sol_status] == 'd_infeas':
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message += " The solution is dual infeasible."
            self.results.solver.Message = self.results.solver.termination_message
            self.results.solver.termination_condition = TerminationCondition.unbounded
            soln.status = SolutionStatus.infeasible

        elif SOLSTA_MAP[sol_status] == 'p_infeas':
            self.results.solver.status = SolverStatus.warning
            self.results.solver.termination_message += " The solution is primal infeasible."
            self.results.solver.Message = self.results.solver.termination_message
            self.results.solver.termination_condition = TerminationCondition.infeasible
            soln.status = SolutionStatus.infeasible

        self.results.problem.name = msk_task.gettaskname()

        if msk_task.getobjsense() == msk.objsense.minimize:
            self.results.problem.sense = minimize
        elif msk_task.getobjsense() == msk.objsense.maximize:
            self.results.problem.sense = maximize
        else:
            raise RuntimeError(
                'Unrecognized Mosek objective sense: {0}'.format(msk_task.getobjname()))

        self.results.problem.upper_bound = None
        self.results.problem.lower_bound = None

        if msk_task.getnumintvar() == 0:
            try:
                if msk_task.getobjsense() == msk.objsense.minimize:
                    self.results.problem.upper_bound = msk_task.getprimalobj(
                        whichsol)
                    self.results.problem.lower_bound = msk_task.getdualobj(
                        whichsol)
                elif msk_task.getobjsense() == msk.objsense.maximize:
                    self.results.problem.upper_bound = msk_task.getprimalobj(
                        whichsol)
                    self.results.problem.lower_bound = msk_task.getdualobj(
                        whichsol)

            except (msk.MosekException, AttributeError):
                pass
        elif msk_task.getobjsense() == msk.objsense.minimize:  # minimizing
            try:
                self.results.problem.upper_bound = msk_task.getprimalobj(
                    whichsol)
            except (msk.MosekException, AttributeError):
                pass
            try:
                self.results.problem.lower_bound = msk_task.getdouinf(
                    msk.dinfitem.mio_obj_bound)
            except (msk.MosekException, AttributeError):
                pass
        elif msk_task.getobjsense() == msk.objsense.maximize:  # maximizing
            try:
                self.results.problem.upper_bound = msk_task.getdouinf(
                    msk.dinfitem.mio_obj_bound)
            except (msk.MosekException, AttributeError):
                pass
            try:
                self.results.problem.lower_bound = msk_task.getprimalobj(
                    whichsol)
            except (msk.MosekException, AttributeError):
                pass
        else:
            raise RuntimeError(
                'Unrecognized Mosek objective sense: {0}'.format(msk_task.getobjsense()))

        try:
            soln.gap = self.results.problem.upper_bound - self.results.problem.lower_bound
        except TypeError:
            soln.gap = None

        self.results.problem.number_of_constraints = msk_task.getnumcon()
        self.results.problem.number_of_nonzeros = msk_task.getnumanz()
        self.results.problem.number_of_variables = msk_task.getnumvar()
        self.results.problem.number_of_integer_variables = msk_task.getnumintvar()
        self.results.problem.number_of_continuous_variables = msk_task.getnumvar() - \
            msk_task.getnumintvar()
        self.results.problem.number_of_objectives = 1
        self.results.problem.number_of_solutions = 1

        # if a solve was stopped by a limit, we still need to check to
        # see if there is a solution available - this may not always
        # be the case, both in LP and MIP contexts.
        if self._save_results:
            """
            This code in this if statement is only needed for backwards compatability. It is more efficient to set
            _save_results to False and use load_vars, load_duals, etc.
            """
            if self.results.problem.number_of_solutions > 0:
                soln_variables = soln.variable
                soln_constraints = soln.constraint

                mosek_vars = list(range(msk_task.getnumvar()))
                mosek_vars = list(set(mosek_vars).intersection(
                    set(self._pyomo_var_to_solver_var_map.values())))
                var_vals = [0.0] * len(mosek_vars)
                self._solver_model.getxx(whichsol, var_vals)
                names = []
                for i in mosek_vars:
                    names.append(msk_task.getvarname(i))

                for mosek_var, val, name in zip(mosek_vars, var_vals, names):
                    pyomo_var = self._solver_var_to_pyomo_var_map[mosek_var]
                    if self._referenced_variables[pyomo_var] > 0:
                        pyomo_var.stale = False
                        soln_variables[name] = {"Value": val}

                if extract_reduced_costs:
                    vals = [0.0]*len(mosek_vars)
                    msk_task.getreducedcosts(
                        whichsol, 0, len(mosek_vars), vals)
                    for mosek_var, val, name in zip(mosek_vars, vals, names):
                        pyomo_var = self._solver_var_to_pyomo_var_map[mosek_var]
                        if self._referenced_variables[pyomo_var] > 0:
                            soln_variables[name]["Rc"] = val

                if extract_duals or extract_slacks:
                    mosek_cons = list(range(msk_task.getnumcon()))
                    con_names = []
                    for con in mosek_cons:
                        con_names.append(msk_task.getconname(con))
                    for name in con_names:
                        soln_constraints[name] = {}
                    """TODO wrong length, needs to be getnumvars()
                    mosek_cones = list(range(msk_task.getnumcone()))
                    cone_names = []
                    for cone in mosek_cones:
                        cone_names.append(msk_task.getconename(cone))
                    for name in cone_names:
                        soln_constraints[name] = {}
                    """

                if extract_duals:
                    ncon = msk_task.getnumcon()
                    if ncon > 0:
                        vals = [0.0]*ncon
                        msk_task.gety(whichsol, vals)
                        for val, name in zip(vals, con_names):
                            soln_constraints[name]["Dual"] = val
                    """TODO: wrong length, needs to be getnumvars()
                    ncone = msk_task.getnumcone()
                    if ncone > 0:
                        vals = [0.0]*ncone
                        msk_task.getsnx(whichsol, vals)
                        for val, name in zip(vals, cone_names):
                            soln_constraints[name]["Dual"] = val
                    """

                if extract_slacks:
                    Ax = [0]*len(mosek_cons)
                    msk_task.getxc(self._whichsol, Ax)
                    for con, name in zip(mosek_cons, con_names):
                        Us = Ls = 0

                        bk, lb, ub = msk_task.getconbound(con)

                        if bk in [msk.boundkey.fx, msk.boundkey.ra, msk.boundkey.up]:
                            Us = ub - Ax[con]
                        if bk in [msk.boundkey.fx, msk.boundkey.ra, msk.boundkey.lo]:
                            Ls = Ax[con] - lb

                        if Us > Ls:
                            soln_constraints[name]["Slack"] = Us
                        else:
                            soln_constraints[name]["Slack"] = -Ls

        elif self._load_solutions:
            if self.results.problem.number_of_solutions > 0:

                self._load_vars()

                if extract_reduced_costs:
                    self._load_rc()

                if extract_duals:
                    self._load_duals()

                if extract_slacks:
                    self._load_slacks()

        self.results.solution.insert(soln)

        # finally, clean any temporary files registered with the temp file
        # manager, created populated *directly* by this plugin.
        TempfileManager.pop(remove=not self._keepfiles)

        return DirectOrPersistentSolver._postsolve(self)

    def warm_start_capable(self):
        return True

    def _warm_start(self):
        for pyomo_var, mosek_var in self._pyomo_var_to_solver_var_map.items():
            if pyomo_var.value is not None:
                for solType in self._mosek.soltype._values:
                    self._solver_model.putxxslice(
                        solType, mosek_var, mosek_var+1, [(pyomo_var.value)])

    def _load_vars(self, vars_to_load=None):
        var_map = self._pyomo_var_to_solver_var_map
        ref_vars = self._referenced_variables
        if vars_to_load is None:
            vars_to_load = var_map.keys()

        mosek_vars_to_load = [var_map[pyomo_var] for pyomo_var in vars_to_load]
        var_vals = [0.0] * len(mosek_vars_to_load)
        self._solver_model.getxx(self._whichsol, var_vals)

        for var, val in zip(vars_to_load, var_vals):
            if ref_vars[var] > 0:
                var.stale = False
                var.value = val

    def _load_rc(self, vars_to_load=None):
        if not hasattr(self._pyomo_model, 'rc'):
            self._pyomo_model.rc = Suffix(direction=Suffix.IMPORT)
        var_map = self._pyomo_var_to_solver_var_map
        ref_vars = self._referenced_variables
        rc = self._pyomo_model.rc
        if vars_to_load is None:
            vars_to_load = var_map.keys()

        mosek_vars_to_load = [var_map[pyomo_var] for pyomo_var in vars_to_load]
        vals = [0.0]*len(mosek_vars_to_load)
        self._solver_model.getreducedcosts(
            self._whichsol, 0, len(mosek_vars_to_load), vals)

        for var, val in zip(vars_to_load, vals):
            if ref_vars[var] > 0:
                rc[var] = val

    def _load_duals(self, objs_to_load=None):
        if not hasattr(self._pyomo_model, 'dual'):
            self._pyomo_model.dual = Suffix(direction=Suffix.IMPORT)
        con_map = self._pyomo_con_to_solver_con_map
        reverse_con_map = self._solver_con_to_pyomo_con_map
        cone_map = self._pyomo_cone_to_solver_cone_map
        reverse_cone_map = self._solver_cone_to_pyomo_cone_map
        dual = self._pyomo_model.dual

        if objs_to_load is None:
            # constraints
            mosek_cons_to_load = range(self._solver_model.getnumcon())
            vals = [0.0]*len(mosek_cons_to_load)
            self._solver_model.gety(self._whichsol, vals)
            for mosek_con, val in zip(mosek_cons_to_load, vals):
                pyomo_con = reverse_con_map[mosek_con]
                dual[pyomo_con] = val
            """TODO wrong length, needs to be getnumvars()
            # cones
            mosek_cones_to_load = range(self._solver_model.getnumcone())
            vals = [0.0]*len(mosek_cones_to_load)
            self._solver_model.getsnx(self._whichsol, vals)
            for mosek_cone, val in zip(mosek_cones_to_load, vals):
                pyomo_cone = reverse_cone_map[mosek_cone]
                dual[pyomo_cone] = val
            """
        else:
            mosek_cons_to_load = []
            mosek_cones_to_load = []
            for obj in objs_to_load:
                if obj in con_map:
                    mosek_cons_to_load.append(con_map[obj])
                else:
                    # assume it is a cone
                    mosek_cones_to_load.append(cone_map[obj])
            # constraints
            mosek_cons_first = min(mosek_cons_to_load)
            mosek_cons_last = max(mosek_cons_to_load)
            vals = [0.0]*(mosek_cons_last - mosek_cons_first + 1)
            self._solver_model.getyslice(self._whichsol,
                                         mosek_cons_first,
                                         mosek_cons_last,
                                         vals)
            for mosek_con in mosek_cons_to_load:
                slice_index = mosek_con - mosek_cons_first
                val = vals[slice_index]
                pyomo_con = reverse_con_map[mosek_con]
                dual[pyomo_con] = val
            """TODO wrong length, needs to be getnumvars()
            # cones
            mosek_cones_first = min(mosek_cones_to_load)
            mosek_cones_last = max(mosek_cones_to_load)
            vals = [0.0]*(mosek_cones_last - mosek_cones_first + 1)
            self._solver_model.getsnxslice(self._whichsol,
                                           mosek_cones_first,
                                           mosek_cones_last,
                                           vals)
            for mosek_cone in mosek_cones_to_load:
                slice_index = mosek_cone - mosek_cones_first
                val = vals[slice_index]
                pyomo_cone = reverse_cone_map[mosek_cone]
                dual[pyomo_cone] = val
            """

    def _load_slacks(self, cons_to_load=None):
        if not hasattr(self._pyomo_model, 'slack'):
            self._pyomo_model.slack = Suffix(direction=Suffix.IMPORT)
        con_map = self._pyomo_con_to_solver_con_map
        reverse_con_map = self._solver_con_to_pyomo_con_map
        slack = self._pyomo_model.slack
        msk = self._mosek

        if cons_to_load is None:
            mosek_cons_to_load = range(self._solver_model.getnumcon())
        else:
            mosek_cons_to_load = set([con_map[pyomo_con]
                                      for pyomo_con in cons_to_load])

        Ax = [0]*len(mosek_cons_to_load)
        self._solver_model.getxc(self._whichsol, Ax)
        for con in mosek_cons_to_load:
            pyomo_con = reverse_con_map[con]
            Us = Ls = 0

            bk, lb, ub = self._solver_model.getconbound(con)

            if bk in [msk.boundkey.fx, msk.boundkey.ra, msk.boundkey.up]:
                Us = ub - Ax[con]
            if bk in [msk.boundkey.fx, msk.boundkey.ra, msk.boundkey.lo]:
                Ls = Ax[con] - lb

            if Us > Ls:
                slack[pyomo_con] = Us
            else:
                slack[pyomo_con] = -Ls

    def load_duals(self, cons_to_load=None):
        """
        Load the duals into the 'dual' suffix. The 'dual' suffix must live on the parent model.

        Parameters
        ----------
        cons_to_load: list of Constraint
        """
        self._load_duals(cons_to_load)

    def load_rc(self, vars_to_load):
        """
        Load the reduced costs into the 'rc' suffix. The 'rc' suffix must live on the parent model.

        Parameters
        ----------
        vars_to_load: list of Var
        """
        self._load_rc(vars_to_load)

    def load_slacks(self, cons_to_load=None):
        """
        Load the values of the slack variables into the 'slack' suffix. The 'slack' suffix must live on the parent
        model.

        Parameters
        ----------
        cons_to_load: list of Constraint
        """
        self._load_slacks(cons_to_load)
Exemple #7
0
    def categorize_variables(model, initial_inputs):
        """Creates lists of time-only-slices of the different types of variables
        in a model, given knowledge of which are inputs. These lists are added 
        as attributes to the model's namespace.

        Possible variable categories are:

            - INPUT --- Those specified by the user to be inputs
            - DERIVATIVE --- Those declared as Pyomo DerivativeVars, whose 
                             "state variable" is not fixed, except possibly as an
                             initial condition
            - DIFFERENTIAL --- Those referenced as the "state variable" by an
                               unfixed (except possibly as an initial condition)
                               DerivativeVar
            - FIXED --- Those that are fixed at non-initial time points. These
                        are typically disturbances, design variables, or 
                        uncertain parameters.
            - ALGEBRAIC --- Unfixed, time-indexed variables that are neither
                            inputs nor referenced by an unfixed derivative.
            - SCALAR --- Variables unindexed by time. These could be variables
                         that refer to a specific point in time (initial or
                         final conditions), averages over time, or truly 
                         time-independent variables like diameter.

        Args:
            model : Model whose variables will be flattened and categorized
            initial_inputs : List of VarData objects that are input variables
                             at the initial time point

        """
        namespace = getattr(model, DynamicBase.get_namespace_name())
        time = namespace.get_time()
        t0 = time.first()
        t1 = time.get_finite_elements()[1]
        deriv_vars = []
        diff_vars = []
        input_vars = []
        alg_vars = []
        fixed_vars = []

        ic_vars = []

        # Create list of time-only-slices of time indexed variables
        # (And list of VarData objects for scalar variables)
        scalar_vars, dae_vars = flatten_dae_components(model, time, Var)

        dae_map = ComponentMap([(v[t0], v) for v in dae_vars])
        t0_vardata = list(dae_map.keys())
        namespace.dae_vars = list(dae_map.values())
        namespace.scalar_vars = \
            NMPCVarGroup(
                list(ComponentMap([(v, v) for v in scalar_vars]).values()),
                index_set=None, is_scalar=True)
        namespace.n_scalar_vars = \
                namespace.scalar_vars.n_vars
        input_set = ComponentSet(initial_inputs)
        updated_input_set = ComponentSet(initial_inputs)

        # Iterate over initial vardata, popping from dae map when an input,
        # derivative, or differential var is found.
        for var0 in t0_vardata:
            if var0 in updated_input_set:
                input_set.remove(var0)
                time_slice = dae_map.pop(var0)
                input_vars.append(time_slice)

            parent = var0.parent_component()
            if not isinstance(parent, DerivativeVar):
                continue
            if not time in ComponentSet(parent.get_continuousset_list()):
                continue
            index0 = var0.index()
            var1 = dae_map[var0][t1]
            index1 = var1.index()
            state = parent.get_state_var()

            if state[index1].fixed:
                # Assume state var is fixed everywhere, so derivative
                # 'isn't really' a derivative.
                # Should be safe to remove state from dae_map here
                state_slice = dae_map.pop(state[index0])
                fixed_vars.append(state_slice)
                continue
            if state[index0] in input_set:
                # If differential variable is an input, then this DerivativeVar
                # is 'not really a derivative'
                continue

            deriv_slice = dae_map.pop(var0)

            if var1.fixed:
                # Assume derivative has been fixed everywhere.
                # Add to list of fixed variables, and don't remove its state variable.
                fixed_vars.append(deriv_slice)
            elif var0.fixed:
                # In this case the derivative has been used as an initial condition.
                # Still want to include it in the list of derivatives.
                ic_vars.append(deriv_slice)
                state_slice = dae_map.pop(state[index0])
                if state[index0].fixed:
                    ic_vars.append(state_slice)
                deriv_vars.append(deriv_slice)
                diff_vars.append(state_slice)
            else:
                # Neither is fixed. This should be the most common case.
                state_slice = dae_map.pop(state[index0])
                if state[index0].fixed:
                    ic_vars.append(state_slice)
                deriv_vars.append(deriv_slice)
                diff_vars.append(state_slice)

        if not updated_input_set:
            raise RuntimeError('Not all inputs could be found')
        assert len(deriv_vars) == len(diff_vars)

        for var0, time_slice in dae_map.items():
            var1 = time_slice[t1]
            # If the variable is still in the list of time-indexed vars,
            # it must either be fixed (not a var) or be an algebraic var
            if var1.fixed:
                fixed_vars.append(time_slice)
            else:
                if var0.fixed:
                    ic_vars.append(time_slice)
                alg_vars.append(time_slice)

        namespace.deriv_vars = NMPCVarGroup(deriv_vars, time)
        namespace.diff_vars = NMPCVarGroup(diff_vars, time)
        namespace.n_diff_vars = len(diff_vars)
        namespace.n_deriv_vars = len(deriv_vars)
        assert (namespace.n_diff_vars == namespace.n_deriv_vars)

        # ic_vars will not be stored as a NMPCVarGroup - don't want to store
        # all the info twice
        namespace.ic_vars = ic_vars
        namespace.n_ic_vars = len(ic_vars)
        #assert model.n_dv == len(ic_vars)
        # Would like this to be true, but accurately detecting differential
        # variables that are not implicitly fixed (by fixing some input)
        # is difficult
        # Also, a categorization can have no input vars and still be
        # valid for MHE

        namespace.input_vars = NMPCVarGroup(input_vars, time)
        namespace.n_input_vars = len(input_vars)

        namespace.alg_vars = NMPCVarGroup(alg_vars, time)
        namespace.n_alg_vars = len(alg_vars)

        namespace.fixed_vars = NMPCVarGroup(fixed_vars, time)
        namespace.n_fixed_vars = len(fixed_vars)

        namespace.variables_categorized = True
Exemple #8
0
 def test_values(self):
     cmap = ComponentMap(self._components)
     self.assertEqual(sorted(cmap.values()),
                      sorted(list(val for c,val in self._components)))