def find_min(constraints, expr, default_min=0):
if type(expr) == int:
return expr
constraint_strs = [f'{c}' for c in constraints]
min_optimize = Optimize()
min_optimize.set('timeout', 10000)
min_optimize.assert_exprs(*constraints)
min_optimize.minimize(expr)
status = min_optimize.check()
if status != sat:
print(f'Unable to find min ({status}) for:\n' +
'\n'.join(constraint_strs))
return None
min_val = min_optimize.model().eval(expr).as_long()
# Make sure it's actually the min, since z3 has a bug
# https://github.com/Z3Prover/z3/issues/4670
solver = Solver()
solver.set('timeout', 10000)
solver.add(constraints + [expr < min_val])
status = solver.check()
if status != unsat:
print(
f'Z3 bug\nFind min ({expr}) => {min_val} with status ({status}):\n'
+ '\n'.join(constraint_strs))
return None
return min_val
def find_max(constraints, expr, l = None):
if l is None:
l = logger
if type(expr) == int:
return expr
constraint_strs = [f'{c}' for c in constraints]
max_optimize = Optimize()
max_optimize.set('timeout', 10000)
max_optimize.assert_exprs(*constraints)
max_optimize.maximize(expr)
status = max_optimize.check()
if status != sat:
l.warning(f'Unable to find max ({status}) for:\n' + '\n'.join(constraint_strs))
return None
max_val = max_optimize.model().eval(expr).as_long()
# Make sure it's actually the max, since z3 has a bug
# https://github.com/Z3Prover/z3/issues/4670
solver = Solver()
solver.set('timeout', 10000)
solver.add(constraints + [expr > max_val])
status = solver.check()
if status != unsat:
l.error(f'Z3 bug\nFind max ({expr}) => {max_val} with status ({status}):\n' + '\n'.join(constraint_strs))
return None
return max_val
