Merge pull request #583 from acco32/fsharp

Add constraint programming examples

examples/fsharp/diet.fsx

@@ -0,0 +1,63 @@
+(*
+
+  Copyright 2012 Hakan Kjellerstrand
+
+  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.
+
+*)
+
+#I "../../bin"
+#r "Google.OrTools.dll"
+
+open Google.OrTools.ConstraintSolver
+
+
+let solver = new Solver("Diet");
+
+let price = [|50; 20; 30; 80|] // in cents
+
+// requirements for each nutrition type
+let limits = [|500; 6; 10; 8|]
+let products = [|"A"; "B"; "C"; "D"|]
+
+// nutritions for each product
+let calories  = [|400L; 200L; 150L; 500L|]
+let chocolate = [|3L; 2L; 0L; 0L|]
+let sugar     = [|2L; 2L; 4L; 4L|]
+let fat       = [|2L; 4L; 1L; 5L|]
+
+let x = solver.MakeIntVarArray(products.Length, 0L, 100L, "x")
+let cost = x.ScalProd(price).Var()
+
+solver.Add( x.ScalProd(calories).solver().MakeGreaterOrEqual(x.ScalProd(calories), limits.[0]) )
+solver.Add( x.ScalProd(chocolate).solver().MakeGreaterOrEqual(x.ScalProd(chocolate), limits.[1]))
+solver.Add( x.ScalProd(sugar).solver().MakeGreaterOrEqual(x.ScalProd(sugar), limits.[2]))
+solver.Add( x.ScalProd(fat).solver().MakeGreaterOrEqual(x.ScalProd(fat), limits.[3]))
+
+let obj = cost.Minimize(1)
+let db = solver.MakePhase(new IntVarVector(x), Solver.CHOOSE_PATH, Solver.ASSIGN_MIN_VALUE)
+
+solver.NewSearch(db, obj)
+while (solver.NextSolution()) do
+  printfn "cost: %d" (cost.Value())
+  printfn "Products: "
+  for i=0 to (products.Length-1) do
+    printfn "%s: %d" products.[i] (x.[i].Value())
+
+
+printfn "\nSolutions: %d" (solver.Solutions())
+printfn "WallTime: %d ms" (solver.WallTime())
+printfn "Failures: %d" (solver.Failures())
+printfn "Branches: %d " (solver.Branches())
+
+solver.EndSearch();

examples/fsharp/rabbit-pheasant.fsx

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+
+#I "../../bin"
+#r "Google.OrTools.dll"
+
+open Google.OrTools.ConstraintSolver
+
+let solver = new Solver("pheasant")
+
+// Variables
+let p = solver.MakeIntVar(0L, 20L, "pheasant")
+let r = solver.MakeIntVar(0L, 20L, "rabbit")
+
+// Constraints
+let legs = solver.MakeSum(solver.MakeProd(p, 2L), solver.MakeProd(r, 4L))
+let heads = solver.MakeSum(p, r)
+
+let constraintLegs = solver.MakeEquality(legs, 56)
+let constraintHeads = solver.MakeEquality(heads, 20)
+
+solver.Add(constraintLegs)
+solver.Add(constraintHeads)
+
+let vars = new IntVarVector([|p; r|])
+let db = solver.MakePhase(vars, Solver.CHOOSE_FIRST_UNBOUND, Solver.ASSIGN_MIN_VALUE)
+
+// Solve
+solver.NewSearch(db)
+
+while (solver.NextSolution()) do
+  printfn "rabbits: %d, pheasants: %d" (r.Value()) (p.Value())
+
+solver.EndSearch()