57 lines
1.9 KiB
Go
57 lines
1.9 KiB
Go
// Copyright 2010-2024 Google LLC
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// The optional_interval_sample_sat command is an example of an Interval variable that is
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// marked as optional.
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package main
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import (
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"fmt"
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"github.com/golang/glog"
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"ortools/sat/go/cpmodel"
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)
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const horizon = 100
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func optionalIntervalSampleSat() error {
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model := cpmodel.NewCpModelBuilder()
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domain := cpmodel.NewDomain(0, horizon)
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x := model.NewIntVarFromDomain(domain).WithName("x")
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y := model.NewIntVar(2, 4).WithName("y")
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z := model.NewIntVarFromDomain(domain).WithName("z")
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presenceVar := model.NewBoolVar().WithName("presence")
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// An optional interval can be created from three affine expressions and a BoolVar.
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intervalVar := model.NewOptionalIntervalVar(x, y, cpmodel.NewConstant(2).Add(z), presenceVar).WithName("interval")
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// If the size is fixed, a simpler version uses the start expression and the size.
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fixedSizeIntervalVar := model.NewOptionalFixedSizeIntervalVar(x, 10, presenceVar).WithName("fixedSizeInterval")
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m, err := model.Model()
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if err != nil {
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return fmt.Errorf("failed to instantiate the CP model: %w", err)
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}
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fmt.Printf("%v\n", m.GetConstraints()[intervalVar.Index()])
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fmt.Printf("%v\n", m.GetConstraints()[fixedSizeIntervalVar.Index()])
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return nil
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}
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func main() {
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if err := optionalIntervalSampleSat(); err != nil {
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glog.Exitf("optionalIntervalSampleSat returned with error: %v", err)
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}
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}
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