OR-Tools  8.2
cp_model_objective.h
Go to the documentation of this file.
1 // Copyright 2010-2018 Google LLC
2 // Licensed under the Apache License, Version 2.0 (the "License");
3 // you may not use this file except in compliance with the License.
4 // You may obtain a copy of the License at
5 //
6 // http://www.apache.org/licenses/LICENSE-2.0
7 //
8 // Unless required by applicable law or agreed to in writing, software
9 // distributed under the License is distributed on an "AS IS" BASIS,
10 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 // See the License for the specific language governing permissions and
12 // limitations under the License.
13 
14 #ifndef OR_TOOLS_SAT_CP_MODEL_OBJECTIVE_H_
15 #define OR_TOOLS_SAT_CP_MODEL_OBJECTIVE_H_
16 
17 #include "ortools/sat/cp_model.pb.h"
18 
19 namespace operations_research {
20 namespace sat {
21 
22 // If the objective contains more than one term, a new integer variable will be
23 // created and an equality constraint will be added to the model to force
24 // this new variable to be equal to the old linear combinaison defining the
25 // objective.
26 //
27 // If the objective contains only one term, we canonicalize it so that its
28 // coefficient is one. If there is no objecitve, this has no effect.
29 //
30 // The main raison to do that is that the objective can be preprocessed like
31 // any linear constraint before beeing "extracted" again.
32 //
33 // TODO(user): Add only a >= constraint? Not sure it is useful to do that before
34 // presolve, we can always do this optimization just before solving the model.
35 void EncodeObjectiveAsSingleVariable(CpModelProto* cp_model);
36 
37 } // namespace sat
38 } // namespace operations_research
39 
40 #endif // OR_TOOLS_SAT_CP_MODEL_OBJECTIVE_H_
void EncodeObjectiveAsSingleVariable(CpModelProto *cp_model)
The vehicle routing library lets one model and solve generic vehicle routing problems ranging from th...