with simplification

examples/python/efsmt.py

@@ -5,43 +5,33 @@ from z3.z3util import get_vars
 Modified from the example in  pysmt
 https://github.com/pysmt/pysmt/blob/97088bf3b0d64137c3099ef79a4e153b10ccfda7/examples/efsmt.py
 '''
-def efsmt(y, phi, maxloops=None):
-    """Solving exists x. forall y. phi(x, y)"""
-    vars = get_vars(phi)
-    x = [item for item in vars if item not in y]
-    esolver = Solver()
-    fsolver = Solver()
-    esolver.add(BoolVal(True))
+
+def efsmt(ys, phi, maxloops = None):
+    """Solving exists xs. forall ys. phi(x, y)"""
+    xs = [x for x in get_vars(phi) if x not in ys]
+    E = Solver()
+    F = Solver()
+    E.add(BoolVal(True))
     loops = 0
     while maxloops is None or loops <= maxloops:
         loops += 1
-        eres = esolver.check()
+        eres = E.check()
         if eres == unsat:
             return unsat
         else:
-            emodel = esolver.model()
-            tau = [emodel.eval(var, True) for var in x]
-            sub_phi = phi
-            for i in range(len(x)):
-                sub_phi = simplify(substitute(sub_phi, (x[i], tau[i])))
-            fsolver.add(Not(sub_phi))
-            if fsolver.check() == sat:
-                fmodel = fsolver.model()
-                sigma = [fmodel.eval(v, True) for v in y]
-                sub_phi = phi
-                for j in range(len(y)):
-                    sub_phi = simplify(substitute(sub_phi, (y[j], sigma[j])))
-                esolver.add(sub_phi)
+            emodel = E.model()
+            sub_phi = substitute(phi, [(x, emodel.eval(x, True)) for x in xs])
+            F.push()
+            F.add(Not(sub_phi))
+            if F.check() == sat:
+                fmodel = F.model()
+                sub_phi = substitute(phi, [(y, fmodel.eval(y, True)) for y in ys])
+                E.add(sub_phi)
             else:
-                return sat
+                return sat, [(x, emodel.eval(x, True)) for x in xs]
+            F.pop()
     return unknown
 
-
-def test():
-    x, y, z = Reals("x y z")
-    fmla = Implies(And(y > 0, y < 10), y - 2 * x < 7)
-    fmlb = And(y > 3, x == 1)
-    print(efsmt([y], fmla))
-    print(efsmt([y], fmlb))
-    
-test()
+x, y, z = Reals("x y z")
+print(efsmt([y], Implies(And(y > 0, y < 10), y - 2 * x < 7)))
+print(efsmt([y], And(y > 3, x == 1)))