Implement parallel python example

examples/python/parallel.py

@@ -0,0 +1,33 @@
+from z3 import *
+from multiprocessing.pool import ThreadPool
+from copy import deepcopy
+
+pool = ThreadPool(8)
+x = Int('x')
+
+assert x.ctx == main_ctx()
+
+
+def calculate(x, n, ctx):
+    """ Do a simple computation with a context"""
+    assert x.ctx == ctx
+    assert x.ctx != main_ctx()
+
+    condition = And(x < 2, x > n, ctx)
+    solver = Solver(ctx=ctx)
+    solver.add(condition)
+    solver.check()
+
+
+for i in range(100):
+    # Create new context for the computation
+    # Note that we need to do this sequentially, as parallel access to the current context or its objects
+    # will result in a segfault
+    i_context = Context()
+    x_i = deepcopy(x).translate(i_context)
+
+    # Kick off parallel computation
+    pool.apply_async(calculate, [x_i, i, i_context])
+
+pool.close()
+pool.join()