# Copyright Contributors to the Pyro project.
# SPDX-License-Identifier: Apache-2.0
from collections import Hashable
from contextlib import contextmanager
import funsor.interpreter as interpreter
@contextmanager
def memoize(cache=None):
"""
Exploit cons-hashing to do implicit common subexpression elimination
"""
if cache is None:
cache = {}
@interpreter.interpretation(interpreter._INTERPRETATION) # use base
def memoize_interpretation(cls, *args):
key = (cls,) + tuple(id(arg) if (type(arg).__name__ == "DeviceArray") or not isinstance(arg, Hashable)
else arg for arg in args)
if key not in cache:
cache[key] = cls(*args)
return cache[key]
with interpreter.interpretation(memoize_interpretation):
yield cache
