interface_example.py runs and prints its values.

examples/interface_example.py

@@ -1,30 +1,56 @@
+from __future__ import division
+
+import sys
+sys.path.append("../src")
+sys.path.append("../tests")
+
 from skypyblue.core import ConstraintSystem
-from skypyblue.models import Strength, Variable
+from skypyblue.models import Constraint, Strength, Variable, Method
 
 cs = ConstraintSystem()
 
-v1 = Variable("v1", 15, cs)
-v2 = Variable("v2", 15, cs)
-v3 = Variable("v3", 15, cs)
+v1 = Variable("v1", 16, cs)
+v2 = Variable("v2", 16, cs)
+v3 = Variable("v3", 16, cs)
 v4 = Variable("v4", 10, cs)
 
-cs.stay(v4, Strength.WEAK)
+v4.stay()
 
 # v1 + v2 = v3, v1 - v2 = v4
 m12_34 = Method([v1, v2], [v3, v4],
   lambda v1, v2: (v1 + v2 , v1 - v2))
 
 m34_12 = Method([v3, v4], [v1, v2],
-  lambda v3, v4: (v3 + v4) / 2 , (v3 - v4) / 2)
+  lambda v3, v4: ((v3 + v4) / 2 , (v3 - v4) / 2))
 
 cn1 = Constraint(
   lambda v1, v2, v3, v4: v1 + v2 == v3 and v1 - v2 == v4,
   Strength.STRONG, 
   [v1, v2, v3, v4], 
   [m12_34, m34_12])
 
-cs.add_constraint(cn1) # sets v3 to 30 and v4 to 0
+cs.add_constraint(cn1)
+
+def print_values():
+  print("v1 = " + str(v1.get_value()))
+  print("v2 = " + str(v2.get_value()))
+  print("v3 = " + str(v3.get_value()))
+  print("v4 = " + str(v4.get_value()))
+print("Constraint: v1 + v2 = v3, v1 - v2 = v4.")
+print_values()
 
+print("Set v1 to 5.")
+v1.set_value(5)
+print_values()
+
+print("Set v2 to 8.")
+v2.set_value(8)
+print_values()
+
+print("Set v3 to 10.")
 v3.set_value(10)
-print(v1.get_value()) # 5
-print(v2.get_value()) # 5
+print_values()
+
+print("Set v4 to 2.")
+v4.set_value(2)
+print_values()