add assert_and_track to optimize for #2116

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/api/python/z3/z3.py

@@ -7336,6 +7336,36 @@ class Optimize(Z3PPObject):
         self.add(fml)
         return self
 
+    def assert_and_track(self, a, p):
+        """Assert constraint `a` and track it in the unsat core using the Boolean constant `p`.
+
+        If `p` is a string, it will be automatically converted into a Boolean constant.
+
+        >>> x = Int('x')
+        >>> p3 = Bool('p3')
+        >>> s = Optimize()
+        >>> s.set(unsat_core=True)
+        >>> s.assert_and_track(x > 0,  'p1')
+        >>> s.assert_and_track(x != 1, 'p2')
+        >>> s.assert_and_track(x < 0,  p3)
+        >>> print(s.check())
+        unsat
+        >>> c = s.unsat_core()
+        >>> len(c)
+        2
+        >>> Bool('p1') in c
+        True
+        >>> Bool('p2') in c
+        False
+        >>> p3 in c
+        True
+        """
+        if isinstance(p, str):
+            p = Bool(p, self.ctx)
+        _z3_assert(isinstance(a, BoolRef), "Boolean expression expected")
+        _z3_assert(isinstance(p, BoolRef) and is_const(p), "Boolean expression expected")
+        Z3_optimize_assert_and_track(self.ctx.ref(), self.optimize, a.as_ast(), p.as_ast())
+
     def add_soft(self, arg, weight = "1", id = None):
         """Add soft constraint with optional weight and optional identifier.
            If no weight is supplied, then the penalty for violating the soft constraint