Ejemplo n.º 1
0
    def apply(self, problem):
        """Returns a new problem and data for inverting the new solution.

        Returns
        -------
        tuple
            (dict of arguments needed for the solver, inverse data)
        """
        data = {}
        inv_data = {self.VAR_ID: problem.variables()[0].id}
        data[s.C], data[s.OFFSET] = ConicSolver.get_coeff_offset(
            problem.objective.args[0])
        data[s.C] = data[s.C].ravel()
        inv_data[s.OFFSET] = data[s.OFFSET][0]

        constr_map = group_constraints(problem.constraints)
        data[ConicSolver.DIMS] = ConeDims(constr_map)

        inv_data[self.EQ_CONSTR] = constr_map[Zero]
        data[s.A], data[s.B] = self.group_coeff_offset(
            problem, constr_map[Zero], ECOS.EXP_CONE_ORDER)

        # Order and group nonlinear constraints.
        neq_constr = constr_map[NonPos] + constr_map[SOC] + constr_map[ExpCone]
        inv_data[self.NEQ_CONSTR] = neq_constr
        data[s.G], data[s.H] = self.group_coeff_offset(
            problem, neq_constr, ECOS.EXP_CONE_ORDER)

        return data, inv_data
Ejemplo n.º 2
0
    def apply(self, problem):
        """Returns a new problem and data for inverting the new solution.

        Returns
        -------
        tuple
            (dict of arguments needed for the solver, inverse data)
        """
        data = {}
        objective, _ = problem.objective.canonical_form
        constraints = [con for c in problem.constraints for con in c.canonical_form[1]]
        data["objective"] = objective
        data["constraints"] = constraints
        data[ConicSolver.DIMS] = ConeDims(
            group_constraints(problem.constraints))
        variables = problem.variables()[0]
        data[s.BOOL_IDX] = [t[0] for t in variables.boolean_idx]
        data[s.INT_IDX] = [t[0] for t in variables.integer_idx]

        inv_data = {self.VAR_ID: problem.variables()[0].id}

        # Order and group constraints.
        eq_constr = [c for c in problem.constraints if type(c) == Zero]
        inv_data[CVXOPT.EQ_CONSTR] = eq_constr
        leq_constr = [c for c in problem.constraints if type(c) == NonPos]
        soc_constr = [c for c in problem.constraints if type(c) == SOC]
        sdp_constr = [c for c in problem.constraints if type(c) == PSD]
        exp_constr = [c for c in problem.constraints if type(c) == ExpCone]
        inv_data[CVXOPT.NEQ_CONSTR] = leq_constr + soc_constr + sdp_constr + exp_constr
        return data, inv_data
Ejemplo n.º 3
0
    def apply(self, problem):
        """Returns a new problem and data for inverting the new solution.

        Returns
        -------
        tuple
            (dict of arguments needed for the solver, inverse data)
        """
        data = {}
        inv_data = {self.VAR_ID: problem.variables()[0].id}

        # Parse the coefficient vector from the objective.
        data[s.C], data[s.OFFSET] = self.get_coeff_offset(
            problem.objective.args[0])
        data[s.C] = data[s.C].ravel()
        inv_data[s.OFFSET] = data[s.OFFSET][0]

        # Order and group nonlinear constraints.
        constr_map = group_constraints(problem.constraints)
        data[ConicSolver.DIMS] = ConeDims(constr_map)
        inv_data[ConicSolver.DIMS] = data[ConicSolver.DIMS]

        # SCS requires constraints to be specified in the following order:
        # 1. zero cone
        # 2. non-negative orthant
        # 3. soc
        # 4. psd
        # 5. exponential
        zero_constr = constr_map[Zero]
        neq_constr = (constr_map[NonPos] + constr_map[SOC] + constr_map[PSD] +
                      constr_map[ExpCone])
        inv_data[SCS.EQ_CONSTR] = zero_constr
        inv_data[SCS.NEQ_CONSTR] = neq_constr

        # Obtain A, b such that Ax + s = b, s \in cones.
        #
        # Note that scs mandates that the cones MUST be ordered with
        # zero cones first, then non-nonnegative orthant, then SOC,
        # then PSD, then exponential.
        data[s.A], data[s.B] = self.group_coeff_offset(
            problem, zero_constr + neq_constr, self.EXP_CONE_ORDER)
        return data, inv_data