65 lines
2.2 KiB
Forth
65 lines
2.2 KiB
Forth
// Copyright 2010-2021 Google
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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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open System
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open Google.OrTools.FSharp
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open Google.OrTools.LinearSolver
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let solver solverType =
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let svr = Solver.CreateSolver(solverType.ToString())
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// x1 and x2 are integer non-negative variables.
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let x1 = svr.MakeIntVar(0.0, Double.PositiveInfinity, "x1")
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let x2 = svr.MakeIntVar(0.0, Double.PositiveInfinity, "x2")
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// Minimize x1 + 2 * x2.
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let objective = svr.Objective()
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objective.SetMinimization()
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objective.SetCoefficient(x1, 1.0)
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objective.SetCoefficient(x2, 2.0)
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// 2 * x2 + 3 * x1 >= 17.
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let ct = svr.MakeConstraint(17.0, Double.PositiveInfinity)
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ct.SetCoefficient(x1, 3.0)
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ct.SetCoefficient(x2, 2.0)
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let resultStatus = svr.Solve()
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// Check that the problem has an optimal solution.
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match resultStatus with
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| status when status <> Solver.ResultStatus.OPTIMAL ->
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printfn "The problem does not have an optimal solution!"
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exit 0
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| _ ->
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printfn "Problem solved in %i milliseconds" (svr.WallTime())
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// The objective value of the solution.
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printfn "Optimal objective value = %f" (objective.Value())
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// The value of each variable in the solution.
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printfn "x1 = %f" (x1.SolutionValue())
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printfn "x2 = %f" (x2.SolutionValue())
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printfn "Advanced usage:"
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printfn "Problem solved in %i branch-and-bound nodes" (svr.Nodes())
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// printfn "---- Integer programming example with %A ----" IntegerProgramming.GLPK
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// solver IntegerProgramming.GLPK
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printfn "---- Linear programming example with %A ----" IntegerProgramming.CBC
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solver IntegerProgramming.CBC
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// printfn "---- Linear programming example with %A ----" IntegerProgramming.SCIP
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// solver IntegerProgramming.SCIP
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