Change infer_broadcastable to infer_static_shape

aesara/tensor/basic.py

@@ -10,7 +10,7 @@ import warnings
 from collections.abc import Sequence
 from functools import partial
 from numbers import Number
-from typing import Optional
+from typing import TYPE_CHECKING, Optional
 from typing import Sequence as TypeSequence
 from typing import Tuple, Union
 from typing import cast as type_cast
@@ -68,6 +68,10 @@ from aesara.tensor.type import (
 from aesara.tensor.var import TensorConstant, TensorVariable, get_unique_value
 
 
+if TYPE_CHECKING:
+    from aesara.tensor import TensorLike
+
+
 def __oplist_tag(thing, tag):
     tags = getattr(thing, "__oplist_tags", [])
     tags.append(tag)
@@ -1334,11 +1338,25 @@ def identity_like(x, dtype: Optional[Union[str, np.generic, np.dtype]] = None):
     return eye(_x.shape[0], _x.shape[1], k=0, dtype=dtype)
 
 
-def infer_broadcastable(shape):
-    """Infer the broadcastable dimensions for `shape`.
+def infer_static_shape(
+    shape: Union[Variable, TypeSequence[Union[Variable, int]]]
+) -> Tuple[TypeSequence["TensorLike"], TypeSequence[Optional[int]]]:
+    """Infer the static shapes implied by the potentially symbolic elements in `shape`.
+
+    `shape` will be validated and constant folded.  As a result, this function
+    can be expensive and shouldn't be used unless absolutely necessary.
+
+    It mostly exists as a hold-over from pre-static shape times, when it was
+    required in order to produce correct broadcastable arrays and prevent
+    some graphs from being unusable.  Now, it is no longer strictly required,
+    so don't use it unless you want the same shape graphs to be rewritten
+    multiple times during graph construction.
+
+    Returns
+    -------
+    A validated sequence of symbolic shape values, and a sequence of
+    ``None``/``int`` values that can be used as `TensorType.shape` values.
 
-    `shape` will be validated and constant folded in order to determine
-    which dimensions are broadcastable (i.e. equal to ``1``).
     """
     from aesara.tensor.rewriting.basic import topo_constant_folding
     from aesara.tensor.rewriting.shape import ShapeFeature
@@ -1362,9 +1380,10 @@ def infer_broadcastable(shape):
         clone=True,
     )
     folded_shape = rewrite_graph(shape_fg, custom_rewrite=topo_constant_folding).outputs
-
-    bcast = tuple(getattr(s, "data", s) == 1 for s in folded_shape)
-    return sh, bcast
+    static_shape = tuple(
+        s.data.item() if isinstance(s, Constant) else None for s in folded_shape
+    )
+    return sh, static_shape
 
 
 class Alloc(COp):
@@ -1394,7 +1413,7 @@ class Alloc(COp):
 
     def make_node(self, value, *shape):
         v = as_tensor_variable(value)
-        sh, bcast = infer_broadcastable(shape)
+        sh, static_shape = infer_static_shape(shape)
         if v.ndim > len(sh):
             raise TypeError(
                 "The Alloc value to use has more dimensions"
@@ -1402,7 +1421,7 @@ class Alloc(COp):
                 v.ndim,
                 len(sh),
             )
-        otype = TensorType(dtype=v.dtype, shape=bcast)
+        otype = TensorType(dtype=v.dtype, shape=static_shape)
         return Apply(self, [v] + sh, [otype()])
 
     def perform(self, node, inputs, out_):
@@ -3823,8 +3842,8 @@ class AllocEmpty(COp):
         return np.dtype(self.dtype).num
 
     def make_node(self, *_shape):
-        _shape, bcast = infer_broadcastable(_shape)
-        otype = TensorType(dtype=self.dtype, shape=bcast)
+        _shape, static_shape = infer_static_shape(_shape)
+        otype = TensorType(dtype=self.dtype, shape=static_shape)
         output = otype()
 
         output.tag.values_eq_approx = values_eq_approx_always_true

aesara/tensor/extra_ops.py

@@ -1646,9 +1646,9 @@ class BroadcastTo(COp):
     def make_node(self, a, *shape):
         a = at.as_tensor_variable(a)
 
-        shape, bcast = at.infer_broadcastable(shape)
+        shape, static_shape = at.infer_static_shape(shape)
 
-        out = TensorType(dtype=a.type.dtype, shape=bcast)()
+        out = TensorType(dtype=a.type.dtype, shape=static_shape)()
 
         # Attempt to prevent in-place operations on this view-based output
         out.tag.indestructible = True
@@ -1670,11 +1670,14 @@ class BroadcastTo(COp):
         d_wrt_a = broadcast_to(dout, shape).sum(axis=new_dims)
 
         # Determine the dimensions that were broadcast
-        _, shape_bcast = at.infer_broadcastable(shape)
+        _, static_shape = at.infer_static_shape(shape)
+
+        # TODO: This needs to be performed at run-time when static shape
+        # information isn't available.
         bcast_sums = [
             i
-            for i, (a_b, s_b) in enumerate(zip(a.broadcastable, shape_bcast[-a.ndim :]))
-            if a_b and not s_b
+            for i, (a_s, s_s) in enumerate(zip(a.type.shape, static_shape[-a.ndim :]))
+            if a_s == 1 and s_s != 1
         ]
 
         if bcast_sums:

aesara/tensor/random/op.py

@@ -14,7 +14,7 @@ from aesara.tensor.basic import (
     constant,
     get_scalar_constant_value,
     get_vector_length,
-    infer_broadcastable,
+    infer_static_shape,
 )
 from aesara.tensor.random.type import RandomGeneratorType, RandomStateType, RandomType
 from aesara.tensor.random.utils import normalize_size_param, params_broadcast_shapes
@@ -322,7 +322,7 @@ class RandomVariable(Op):
             )
 
         shape = self._infer_shape(size, dist_params)
-        _, bcast = infer_broadcastable(shape)
+        _, static_shape = infer_static_shape(shape)
         dtype = self.dtype or dtype
 
         if dtype == "floatX":
@@ -336,7 +336,7 @@ class RandomVariable(Op):
             dtype_idx = constant(dtype, dtype="int64")
             dtype = all_dtypes[dtype_idx.data]
 
-        outtype = TensorType(dtype=dtype, shape=bcast)
+        outtype = TensorType(dtype=dtype, shape=static_shape)
         out_var = outtype()
         inputs = (rng, size, dtype_idx) + dist_params
         outputs = (rng.type(), out_var)

tests/tensor/rewriting/test_basic.py

@@ -276,8 +276,9 @@ class TestLocalCanonicalizeAlloc:
 
         assert a.owner and isinstance(a.owner.op, Alloc)
 
-        # `local_useless_alloc` should replace the `Alloc` with an `Assert`
-        with pytest.raises(AssertionError):
+        # `local_useless_alloc` should attempt to replace the `Alloc` with an
+        # `Assert` and fail when the static shape information conflicts.
+        with pytest.raises(TypeError):
             f = function([], a, mode=rewrite_mode)
 
         x = at.as_tensor(self.rng.standard_normal((6, 7)))

tests/tensor/test_basic.py

@@ -55,7 +55,7 @@ from aesara.tensor.basic import (
     get_vector_length,
     horizontal_stack,
     identity_like,
-    infer_broadcastable,
+    infer_static_shape,
     inverse_permutation,
     join,
     make_vector,
@@ -796,20 +796,20 @@ class TestAlloc:
 
 def test_infer_broadcastable():
     with pytest.raises(TypeError, match="^Shapes must be scalar integers.*"):
-        infer_broadcastable([constant(1.0)])
+        infer_static_shape([constant(1.0)])
 
     with config.change_flags(exception_verbosity="high"), pytest.raises(
         TypeError, match=r"A\. x"
     ):
-        infer_broadcastable([dscalar("x")])
+        infer_static_shape([dscalar("x")])
 
     with pytest.raises(ValueError, match=".*could not be cast to have 0 dimensions"):
-        infer_broadcastable((as_tensor_variable([[1, 2]]),))
+        infer_static_shape((as_tensor_variable([[1, 2]]),))
 
     constant_size = constant([1])
     specify_size = specify_shape(constant_size, [1])
-    sh, bcast = infer_broadcastable(specify_size)
-    assert bcast == (True,)
+    sh, static_shape = infer_static_shape(specify_size)
+    assert static_shape == (1,)
 
 
 # This is slow for the ('int8', 3) version.