integer optimization

STRIPPED/lo_simple.py

@@ -1,6 +1,6 @@
 from pyscipopt import Model
 
-model = Model("Wine blending (simple version)")
+model = Model("Simple linear optimization")
 
 x1 = model.addVar(vtype="C", name="x1")
 x2 = model.addVar(vtype="C", name="x2")

STRIPPED/puzzle.py

@@ -0,0 +1,22 @@
+from pyscipopt import Model
+
+model = Model("Simple linear optimization")
+
+x = model.addVar(vtype="I", name="x")
+y = model.addVar(vtype="I", name="y")
+z = model.addVar(vtype="I", name="x")
+
+model.addCons(x + y + z == 32,"Heads")
+model.addCons(2*x + 4*y + 8*z == 80,"Legs")
+model.setObjective(y + z, "minimize")
+
+model.optimize()
+
+if model.getStatus() == "optimal":
+    print("Optimal value:", model.getObjVal())
+    print("Solution:")
+    print("  x = ", model.getVal(x))
+    print("  y = ", model.getVal(y))
+    print("  z = ", model.getVal(z))
+else:
+    print("Problem could not be solved to optimality")

src/lo_simple.py

@@ -1,5 +1,5 @@
 """
-lo-wines-simple.py: Simple SCIP example of linear programming:
+lo_simple.py: Simple SCIP example of linear programming:
 
 maximize  15x + 18y + 30z
 subject to 2x +   y +   z <= 60
@@ -11,7 +11,7 @@
 """
 from pyscipopt import Model
 
-model = Model("Wine blending (simple version)")
+model = Model("Simple linear optimization")
 
 x1 = model.addVar(vtype="C", name="x1")
 x2 = model.addVar(vtype="C", name="x2")

src/puzzle.py

@@ -0,0 +1,32 @@
+"""
+puzzle.py: Simple SCIP example of integer programming:
+
+maximize  y + z
+subject to x + y + z = 32
+           2x + 4y + 8z = 80
+           x,y,z >= 0 and integer
+
+Copyright (c) by Joao Pedro PEDROSO and Mikio KUBO, 2015
+"""
+from pyscipopt import Model
+
+model = Model("Simple linear optimization")
+
+x = model.addVar(vtype="I", name="x")
+y = model.addVar(vtype="I", name="y")
+z = model.addVar(vtype="I", name="x")
+
+model.addCons(x + y + z == 32,"Heads")
+model.addCons(2*x + 4*y + 8*z == 80,"Legs")
+model.setObjective(y + z, "minimize")
+
+model.optimize()
+
+if model.getStatus() == "optimal":
+    print("Optimal value:", model.getObjVal())
+    print("Solution:")
+    print("  x = ", model.getVal(x))
+    print("  y = ", model.getVal(y))
+    print("  z = ", model.getVal(z))
+else:
+    print("Problem could not be solved to optimality")