model_parameters.proto

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// Copyright 2010-2024 Google LLC
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
// Solve parameters that are specific to the model.
 
syntax = "proto3";
 
package operations_research.math_opt;
 
import "ortools/math_opt/solution.proto";
import "ortools/math_opt/sparse_containers.proto";
 
option java_package = "com.google.ortools.mathopt";
option java_multiple_files = true;
 
// A suggested starting solution for the solver.
//
// MIP solvers generally only want primal information (`variable_values`), while
// LP solvers want both primal and dual information (`dual_values`).
//
// Many MIP solvers can work with: (1) partial solutions that do not specify all
// variables or (2) infeasible solutions. In these cases, solvers typically
// solve a sub-MIP to complete/correct the hint.
//
// How the hint is used by the solver, if at all, is highly dependent on the
// solver, the problem type, and the algorithm used. The most reliable way to
// ensure your hint has an effect is to read the underlying solvers logs with
// and without the hint.
//
// Simplex-based LP solvers typically prefer an initial basis to a solution hint
// (they need to crossover to convert the hint to a basic feasible solution
// otherwise).
//
// TODO(b/183616124): Add hint-priorities to variable_values.
message SolutionHintProto {
  // A possibly partial assignment of values to the primal variables of the
  // problem. The solver-independent requirements for this sub-message are:
  //  * variable_values.ids are elements of VariablesProto.ids.
  //  * variable_values.values must all be finite.
  SparseDoubleVectorProto variable_values = 1;
 
  // A (potentially partial) assignment of values to the linear constraints of
  // the problem.
  //
  //  Requirements:
  //   * dual_values.ids are elements of LinearConstraintsProto.ids.
  //   * dual_values.values must all be finite.
  SparseDoubleVectorProto dual_values = 2;
}
 
// Parameters for an individual objective in a multi-objective model.
message ObjectiveParametersProto {
  // Optional objective degradation absolute tolerance. For a hierarchical
  // multi-objective solver, each objective fⁱ is processed in priority order:
  // the solver determines the optimal objective value Γⁱ, if it exists, subject
  // to all constraints in the model and the additional constraints that
  // fᵏ(x) = Γᵏ (within tolerances) for each k < i. If set, a solution is
  // considered to be "within tolerances" for this objective fᵏ if
  // |fᵏ(x) - Γᵏ| ≤ `objective_degradation_absolute_tolerance`.
  //
  // See also `objective_degradation_relative_tolerance`; if both parameters are
  // set for a given objective, the solver need only satisfy one to be
  // considered "within tolerances".
  //
  //  If set, must be nonnegative.
  optional double objective_degradation_absolute_tolerance = 7;
 
  // Optional objective degradation relative tolerance. For a hierarchical
  // multi-objective solver, each objective fⁱ is processed in priority order:
  // the solver determines the optimal objective value Γⁱ, if it exists, subject
  // to all constraints in the model and the additional constraints that
  // fᵏ(x) = Γᵏ (within tolerances) for each k < i. If set, a solution is
  // considered to be "within tolerances" for this objective fᵏ if
  // |fᵏ(x) - Γᵏ| ≤ `objective_degradation_relative_tolerance` * |Γᵏ|.
  //
  // See also `objective_degradation_absolute_tolerance`; if both parameters are
  // set for a given objective, the solver need only satisfy one to be
  // considered "within tolerances".
  //
  //  If set, must be nonnegative.
  optional double objective_degradation_relative_tolerance = 8;
}
 
// TODO(b/183628247): follow naming convention in fields below.
// Parameters to control a single solve that are specific to the input model
// (see SolveParametersProto for model independent parameters).
message ModelSolveParametersProto {
  // Filter that is applied to all returned sparse containers keyed by variables
  // in PrimalSolutionProto and PrimalRayProto
  // (PrimalSolutionProto.variable_values, PrimalRayProto.variable_values).
  //
  // Requirements:
  //  * filtered_ids are elements of VariablesProto.ids.
  SparseVectorFilterProto variable_values_filter = 1;
 
  // Filter that is applied to all returned sparse containers keyed by linear
  // constraints in DualSolutionProto and DualRay
  // (DualSolutionProto.dual_values, DualRay.dual_values).
  //
  // Requirements:
  //  * filtered_ids are elements of LinearConstraints.ids.
  SparseVectorFilterProto dual_values_filter = 2;
 
  // Filter that is applied to all returned sparse containers keyed by quadratic
  // constraints in DualSolutionProto and DualRay
  // (DualSolutionProto.quadratic_dual_values, DualRay.quadratic_dual_values).
  //
  // Requirements:
  //  * filtered_ids are keys of ModelProto.quadratic_constraints.
  SparseVectorFilterProto quadratic_dual_values_filter = 10;
 
  // Filter that is applied to all returned sparse containers keyed by variables
  // in DualSolutionProto and DualRay (DualSolutionProto.reduced_costs,
  // DualRay.reduced_costs).
  //
  // Requirements:
  //  * filtered_ids are elements of VariablesProto.ids.
  SparseVectorFilterProto reduced_costs_filter = 3;
 
  // Optional initial basis for warm starting simplex LP solvers. If set, it is
  // expected to be valid according to `ValidateBasis` in
  // `validators/solution_validator.h` for the current `ModelSummary`.
  BasisProto initial_basis = 4;
 
  // Optional solution hints. If the underlying solver only accepts a single
  // hint, the first hint is used.
  repeated SolutionHintProto solution_hints = 5;
 
  // Optional branching priorities. Variables with higher values will be
  // branched on first. Variables for which priorities are not set get the
  // solver's default priority (usually zero).
  //
  // Requirements:
  //  * branching_priorities.values must be finite.
  //  * branching_priorities.ids must be elements of VariablesProto.ids.
  SparseInt32VectorProto branching_priorities = 6;
 
  // Optional parameters for the primary objective in a multi-objective model.
  ObjectiveParametersProto primary_objective_parameters = 7;
 
  // Optional parameters for the auxiliary objectives in a multi-objective
  // model.
  //
  // Requirements:
  //  * Map keys must also be map keys of ModelProto.auxiliary_objectives.
  map<int64, ObjectiveParametersProto> auxiliary_objective_parameters = 8;
 
  // Optional lazy constraint annotations. Included linear constraints will be
  // marked as "lazy" with supporting solvers, meaning that they will only be
  // added to the working model as-needed as the solver runs.
  //
  // Note that this an algorithmic hint that does not affect the model's
  // feasible region; solvers not supporting these annotations will simply
  // ignore it.
  //
  // Requirements:
  //  * Each entry must be an element of VariablesProto.ids.
  //  * Entries must be in strictly increasing order (i.e., sorted, no repeats).
  repeated int64 lazy_linear_constraint_ids = 9;
}