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https://github.com/ROCm/jax.git
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902c149c47
This change allows one side of a cond to have a different const-ness
from the other side, from the point-of-view of partial evaluation. In
other words, this now works as expected:
```python
lax.cond(x < 0, x, lambda x: 0., x, lambda x: x) # relu
```
The partial evaluation logic works with tuples, so this works too:
```python
lax.cond(x < 0,
x, lambda x: (x, x, 1, 1, 1),
x, lambda x: (x, 1, x, 1, 2))
```
in that true_fun is resolved to something like `lambda x: (x, x, 1, *, 1)`
and false_fun is resolved to something like `lambda x: (x, 1, x, *, 2)`,
where `*` means unit and corresponds to a known constant that isn't
staged into the computation.
For forward-mode autodiff support, we'll need to add yet another lattice
join on the lattice of symbolic-zero-or-not.
71 lines
2.3 KiB
Python
71 lines
2.3 KiB
Python
# Copyright 2018 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# https://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from __future__ import absolute_import
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from __future__ import division
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from __future__ import print_function
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from .core import pack
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from .tree_util import (build_tree, process_pytree, tree_flatten,
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tree_unflatten, leaf)
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from .linear_util import transformation_with_aux
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from .util import safe_map, unzip2, partial, curry
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map = safe_map
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@curry
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def wraps(wrapped, fun, namestr="{fun}", docstr="{doc}", **kwargs):
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try:
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fun.__name__ = namestr.format(fun=get_name(wrapped))
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fun.__module__ = get_module(wrapped)
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fun.__doc__ = docstr.format(fun=get_name(wrapped), doc=get_doc(wrapped), **kwargs)
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fun.__wrapped__ = wrapped
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finally:
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return fun
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def get_name(fun): return getattr(fun, "__name__", "<unnamed function>")
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def get_module(fun): return getattr(fun, "__module__", "<unknown module>")
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def get_doc(fun): return getattr(fun, "__doc__", "")
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@transformation_with_aux
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def pytree_fun_to_jaxtupletree_fun(in_trees, *args):
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py_args = map(build_tree, in_trees, args)
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ans = yield py_args
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yield pytree_to_jaxtupletree(ans)
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def apply_jaxtree_fun(fun, io_tree, *py_args):
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in_trees_expected, out_tree = io_tree
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args, in_trees = unzip2(map(pytree_to_jaxtupletree, py_args))
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for i, (in_tree, expected) in enumerate(zip(in_trees, in_trees_expected)):
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if in_tree != expected:
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raise TypeError("Expected {}, got {}".format(expected, in_tree))
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ans = fun(*args)
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return build_tree(out_tree, ans)
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pytree_to_jaxtupletree = partial(process_pytree, pack)
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@transformation_with_aux
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def pytree_fun_to_flatjaxtuple_fun(in_trees, *args):
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py_args = map(tree_unflatten, in_trees, args)
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ans = yield py_args
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yield pytree_to_flatjaxtuple(ans)
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def pytree_to_flatjaxtuple(pytree):
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flat_ans, out_tree = tree_flatten(pytree)
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return pack(flat_ans), out_tree
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