Faster graph traversal functions

pytensor/graph/basic.py

@@ -5,7 +5,6 @@ import warnings
 from collections.abc import (
     Hashable,
     Iterable,
-    Reversible,
     Sequence,
 )
 from copy import copy
@@ -961,7 +960,7 @@ def clone_node_and_cache(
 
 def clone_get_equiv(
     inputs: Iterable[Variable],
-    outputs: Reversible[Variable],
+    outputs: Iterable[Variable],
     copy_inputs: bool = True,
     copy_orphans: bool = True,
     memo: dict[Union[Apply, Variable, "Op"], Union[Apply, Variable, "Op"]]
@@ -1002,7 +1001,7 @@ def clone_get_equiv(
         Keywords passed to `Apply.clone_with_new_inputs`.
 
     """
-    from pytensor.graph.traversal import io_toposort
+    from pytensor.graph.traversal import toposort
 
     if memo is None:
         memo = {}
@@ -1018,7 +1017,7 @@ def clone_get_equiv(
             memo.setdefault(input, input)
 
     # go through the inputs -> outputs graph cloning as we go
-    for apply in io_toposort(inputs, outputs):
+    for apply in toposort(outputs, blockers=inputs):
         for input in apply.inputs:
             if input not in memo:
                 if not isinstance(input, Constant) and copy_orphans:

pytensor/graph/features.py

@@ -10,7 +10,7 @@ import numpy as np
 import pytensor
 from pytensor.configdefaults import config
 from pytensor.graph.basic import Variable
-from pytensor.graph.traversal import io_toposort
+from pytensor.graph.traversal import toposort
 from pytensor.graph.utils import InconsistencyError
 
 
@@ -340,11 +340,11 @@ class Feature:
 
 class Bookkeeper(Feature):
     def on_attach(self, fgraph):
-        for node in io_toposort(fgraph.inputs, fgraph.outputs):
+        for node in toposort(fgraph.outputs):
             self.on_import(fgraph, node, "on_attach")
 
     def on_detach(self, fgraph):
-        for node in io_toposort(fgraph.inputs, fgraph.outputs):
+        for node in toposort(fgraph.outputs):
             self.on_prune(fgraph, node, "Bookkeeper.detach")
 
 

pytensor/graph/fg.py

@@ -19,7 +19,8 @@ from pytensor.graph.op import Op
 from pytensor.graph.traversal import (
     applys_between,
     graph_inputs,
-    io_toposort,
+    toposort,
+    toposort_with_orderings,
     vars_between,
 )
 from pytensor.graph.utils import MetaObject, MissingInputError, TestValueError
@@ -366,7 +367,7 @@ class FunctionGraph(MetaObject):
         # new nodes, so we use all variables we know of as if they were the
         # input set.  (The functions in the graph module only use the input set
         # to know where to stop going down.)
-        new_nodes = io_toposort(self.variables, apply_node.outputs)
+        new_nodes = tuple(toposort(apply_node.outputs, blockers=self.variables))
 
         if check:
             for node in new_nodes:
@@ -759,7 +760,7 @@ class FunctionGraph(MetaObject):
             # No sorting is necessary
             return list(self.apply_nodes)
 
-        return io_toposort(self.inputs, self.outputs, self.orderings())
+        return list(toposort_with_orderings(self.outputs, orderings=self.orderings()))
 
     def orderings(self) -> dict[Apply, list[Apply]]:
         """Return a map of node to node evaluation dependencies.

pytensor/graph/replace.py

@@ -10,7 +10,10 @@ from pytensor.graph.basic import (
 )
 from pytensor.graph.fg import FunctionGraph
 from pytensor.graph.op import Op
-from pytensor.graph.traversal import io_toposort, truncated_graph_inputs
+from pytensor.graph.traversal import (
+    toposort,
+    truncated_graph_inputs,
+)
 
 
 ReplaceTypes = Iterable[tuple[Variable, Variable]] | dict[Variable, Variable]
@@ -295,7 +298,7 @@ def vectorize_graph(
     new_inputs = [replace.get(inp, inp) for inp in inputs]
 
     vect_vars = dict(zip(inputs, new_inputs, strict=True))
-    for node in io_toposort(inputs, seq_outputs):
+    for node in toposort(seq_outputs, blockers=inputs):
         vect_inputs = [vect_vars.get(inp, inp) for inp in node.inputs]
         vect_node = vectorize_node(node, *vect_inputs)
         for output, vect_output in zip(node.outputs, vect_node.outputs, strict=True):

pytensor/graph/rewriting/basic.py

@@ -27,7 +27,7 @@ from pytensor.graph.features import AlreadyThere, Feature
 from pytensor.graph.fg import FunctionGraph, Output
 from pytensor.graph.op import Op
 from pytensor.graph.rewriting.unify import OpPattern, Var, convert_strs_to_vars
-from pytensor.graph.traversal import applys_between, io_toposort, vars_between
+from pytensor.graph.traversal import applys_between, toposort, vars_between
 from pytensor.graph.utils import AssocList, InconsistencyError
 from pytensor.misc.ordered_set import OrderedSet
 from pytensor.utils import flatten
@@ -2010,7 +2010,7 @@ class WalkingGraphRewriter(NodeProcessingGraphRewriter):
         callback_before = fgraph.execute_callbacks_time
         nb_nodes_start = len(fgraph.apply_nodes)
         t0 = time.perf_counter()
-        q = deque(io_toposort(fgraph.inputs, start_from))
+        q = deque(toposort(start_from))
         io_t = time.perf_counter() - t0
 
         def importer(node):
@@ -2341,7 +2341,7 @@ class EquilibriumGraphRewriter(NodeProcessingGraphRewriter):
             changed |= apply_cleanup(iter_cleanup_sub_profs)
 
             topo_t0 = time.perf_counter()
-            q = deque(io_toposort(fgraph.inputs, start_from))
+            q = deque(toposort(start_from))
             io_toposort_timing.append(time.perf_counter() - topo_t0)
 
             nb_nodes.append(len(q))

pytensor/printing.py

@@ -21,7 +21,7 @@ from pytensor.configdefaults import config
 from pytensor.graph.basic import Apply, Constant, Variable
 from pytensor.graph.fg import FunctionGraph
 from pytensor.graph.op import HasInnerGraph, Op, StorageMapType
-from pytensor.graph.traversal import graph_inputs, io_toposort
+from pytensor.graph.traversal import graph_inputs, toposort
 from pytensor.graph.utils import Scratchpad
 
 
@@ -1103,7 +1103,7 @@ class PPrinter(Printer):
         )
         inv_updates = {b: a for (a, b) in updates.items()}
         i = 1
-        for node in io_toposort([*inputs, *updates], [*outputs, *updates.values()]):
+        for node in toposort([*outputs, *updates.values()], [*inputs, *updates]):
             for output in node.outputs:
                 if output in inv_updates:
                     name = str(inv_updates[output])

pytensor/scan/rewriting.py

@@ -13,7 +13,6 @@ from pytensor import tensor as pt
 from pytensor.compile import optdb
 from pytensor.compile.function.types import deep_copy_op
 from pytensor.configdefaults import config
-from pytensor.graph import ancestors, graph_inputs
 from pytensor.graph.basic import (
     Apply,
     Constant,
@@ -35,7 +34,11 @@ from pytensor.graph.rewriting.basic import (
 )
 from pytensor.graph.rewriting.db import EquilibriumDB, SequenceDB
 from pytensor.graph.rewriting.utils import get_clients_at_depth
-from pytensor.graph.traversal import apply_depends_on, io_toposort
+from pytensor.graph.traversal import (
+    ancestors,
+    apply_depends_on,
+    graph_inputs,
+)
 from pytensor.graph.type import HasShape
 from pytensor.graph.utils import InconsistencyError
 from pytensor.raise_op import Assert
@@ -220,7 +223,7 @@ def scan_push_out_non_seq(fgraph, node):
     """
     node_inputs, node_outputs = node.op.inner_inputs, node.op.inner_outputs
 
-    local_fgraph_topo = io_toposort(node_inputs, node_outputs)
+    local_fgraph_topo = node.op.fgraph.toposort()
     local_fgraph_outs_set = set(node_outputs)
     local_fgraph_outs_map = {v: k for k, v in enumerate(node_outputs)}
 
@@ -427,7 +430,7 @@ def scan_push_out_seq(fgraph, node):
     """
     node_inputs, node_outputs = node.op.inner_inputs, node.op.inner_outputs
 
-    local_fgraph_topo = io_toposort(node_inputs, node_outputs)
+    local_fgraph_topo = node.op.fgraph.toposort()
     local_fgraph_outs_set = set(node_outputs)
     local_fgraph_outs_map = {v: k for k, v in enumerate(node_outputs)}
 
@@ -840,22 +843,42 @@ def scan_push_out_add(fgraph, node):
 
     # apply_ancestors(args.inner_outputs)
 
-    # Use `ScanArgs` to parse the inputs and outputs of scan for ease of
-    # use
-    args = ScanArgs(
-        node.inputs, node.outputs, op.inner_inputs, op.inner_outputs, op.info
+    add_of_dot_nodes = [
+        n
+        for n in op.fgraph.apply_nodes
+        if
+        (
+            # We have an Add
+            isinstance(n.op, Elemwise)
+            and isinstance(n.op.scalar_op, ps.Add)
+            and any(
+                (
+                    # With a Dot input that's only used in the Add
+                    n_inp.owner is not None
+                    and isinstance(n_inp.owner.op, Dot)
+                    and len(op.fgraph.clients[n_inp]) == 1
+                )
+                for n_inp in n.inputs
             )
+        )
+    ]
+
+    if not add_of_dot_nodes:
+        return False
 
-    clients = {}
-    local_fgraph_topo = io_toposort(
-        args.inner_inputs, args.inner_outputs, clients=clients
+    # Use `ScanArgs` to parse the inputs and outputs of scan for ease of access
+    args = ScanArgs(
+        node.inputs,
+        node.outputs,
+        op.inner_inputs,
+        op.inner_outputs,
+        op.info,
+        clone=False,
     )
 
-    for nd in local_fgraph_topo:
+    for nd in add_of_dot_nodes:
         if (
-            isinstance(nd.op, Elemwise)
-            and isinstance(nd.op.scalar_op, ps.Add)
-            and nd.out in args.inner_out_sit_sot
+            nd.out in args.inner_out_sit_sot
             # FIXME: This function doesn't handle `sitsot_out[1:][-1]` pattern
             and inner_sitsot_only_last_step_used(fgraph, nd.out, args)
         ):
@@ -863,27 +886,17 @@ def scan_push_out_add(fgraph, node):
             # the add from a previous iteration of the inner function
             sitsot_idx = args.inner_out_sit_sot.index(nd.out)
             if args.inner_in_sit_sot[sitsot_idx] in nd.inputs:
-                # Ensure that the other input to the add is a dot product
-                # between 2 matrices which will become a tensor3 and a
-                # matrix if pushed outside of the scan. Also make sure
-                # that the output of the Dot is ONLY used by the 'add'
-                # otherwise doing a Dot in the outer graph will only
-                # duplicate computation.
-
                 sitsot_in_idx = nd.inputs.index(args.inner_in_sit_sot[sitsot_idx])
 
                 # 0 if sitsot_in_idx==1, 1 if sitsot_in_idx==0
                 dot_in_idx = 1 - sitsot_in_idx
-
                 dot_input = nd.inputs[dot_in_idx]
+                assert dot_input.owner is not None and isinstance(
+                    dot_input.owner.op, Dot
+                )
 
                 if (
-                    dot_input.owner is not None
-                    and isinstance(dot_input.owner.op, Dot)
-                    and len(clients[dot_input]) == 1
-                    and dot_input.owner.inputs[0].ndim == 2
-                    and dot_input.owner.inputs[1].ndim == 2
-                    and get_outer_ndim(dot_input.owner.inputs[0], args) == 3
+                    get_outer_ndim(dot_input.owner.inputs[0], args) == 3
                     and get_outer_ndim(dot_input.owner.inputs[1], args) == 3
                 ):
                     # The optimization can be be applied in this case.

pytensor/tensor/rewriting/blas.py

@@ -59,7 +59,7 @@ import time
 
 import numpy as np
 
-from pytensor.graph.traversal import io_toposort
+from pytensor.graph.traversal import toposort
 from pytensor.tensor.rewriting.basic import register_specialize
 
 
@@ -460,6 +460,9 @@ class GemmOptimizer(GraphRewriter):
             callbacks_before = fgraph.execute_callbacks_times.copy()
             callback_before = fgraph.execute_callbacks_time
 
+        nodelist = list(toposort(fgraph.outputs))
+        nodelist.reverse()
+
         def on_import(new_node):
             if new_node is not node:
                 nodelist.append(new_node)
@@ -471,10 +474,8 @@ class GemmOptimizer(GraphRewriter):
         while did_something:
             nb_iter += 1
             t0 = time.perf_counter()
-            nodelist = io_toposort(fgraph.inputs, fgraph.outputs)
             time_toposort += time.perf_counter() - t0
             did_something = False
-            nodelist.reverse()
             for node in nodelist:
                 if not (
                     isinstance(node.op, Elemwise)

tests/compile/test_profiling.py

@@ -50,22 +50,13 @@ class TestProfiling:
             the_string = buf.getvalue()
             lines1 = [l for l in the_string.split("\n") if "Max if linker" in l]
             lines2 = [l for l in the_string.split("\n") if "Minimum peak" in l]
-            if config.device == "cpu":
-                assert "CPU: 4112KB (4104KB)" in the_string, (lines1, lines2)
-                assert "CPU: 8204KB (8196KB)" in the_string, (lines1, lines2)
+            # NODE: The specific numbers can change for distinct (but correct) toposort orderings
+            #  Update the test values if a different algorithm is used
+            assert "CPU: 4112KB (4112KB)" in the_string, (lines1, lines2)
+            assert "CPU: 8204KB (8204KB)" in the_string, (lines1, lines2)
             assert "CPU: 8208KB" in the_string, (lines1, lines2)
             assert (
-                    "Minimum peak from all valid apply node order is 4104KB"
-                    in the_string
-                ), (lines1, lines2)
-            else:
-                assert "CPU: 16KB (16KB)" in the_string, (lines1, lines2)
-                assert "GPU: 8204KB (8204KB)" in the_string, (lines1, lines2)
-                assert "GPU: 12300KB (12300KB)" in the_string, (lines1, lines2)
-                assert "GPU: 8212KB" in the_string, (lines1, lines2)
-                assert (
-                    "Minimum peak from all valid apply node order is 4116KB"
-                    in the_string
+                "Minimum peak from all valid apply node order is 4104KB" in the_string
             ), (lines1, lines2)
 
         finally:

tests/graph/rewriting/test_kanren.py

@@ -160,7 +160,7 @@ def test_KanrenRelationSub_dot():
 
     assert expr_opt.owner.op == pt.add
     assert isinstance(expr_opt.owner.inputs[0].owner.op, Dot)
-    assert fgraph_opt.inputs[0] is A_pt
+    assert fgraph_opt.inputs[-1] is A_pt
     assert expr_opt.owner.inputs[0].owner.inputs[0].name == "A"
     assert expr_opt.owner.inputs[1].owner.op == pt.add
     assert isinstance(expr_opt.owner.inputs[1].owner.inputs[0].owner.op, Dot)

tests/graph/test_fg.py

@@ -56,7 +56,7 @@ class TestFunctionGraph:
         with pytest.raises(TypeError, match="'Variable' object is not iterable"):
             FunctionGraph(var1, [var2])
 
-        with pytest.raises(TypeError, match="'Variable' object is not reversible"):
+        with pytest.raises(TypeError, match="'Variable' object is not iterable"):
             FunctionGraph([var1], var2)
 
         with pytest.raises(

tests/graph/test_replace.py

@@ -28,7 +28,7 @@ class TestCloneReplace:
 
         f1 = z * (x + y) ** 2 + 5
         f2 = clone_replace(f1, replace=None, rebuild_strict=True, copy_inputs_over=True)
-        f2_inp = graph_inputs([f2])
+        f2_inp = tuple(graph_inputs([f2]))
 
         assert z in f2_inp
         assert x in f2_inp
@@ -65,7 +65,7 @@ class TestCloneReplace:
         f2 = clone_replace(
             f1, replace={y: y2}, rebuild_strict=True, copy_inputs_over=True
         )
-        f2_inp = graph_inputs([f2])
+        f2_inp = tuple(graph_inputs([f2]))
         assert z in f2_inp
         assert x in f2_inp
         assert y2 in f2_inp
@@ -83,7 +83,7 @@ class TestCloneReplace:
         f2 = clone_replace(
             f1, replace={y: y2}, rebuild_strict=False, copy_inputs_over=True
         )
-        f2_inp = graph_inputs([f2])
+        f2_inp = tuple(graph_inputs([f2]))
         assert z in f2_inp
         assert x in f2_inp
         assert y2 in f2_inp

tests/graph/test_traversal.py

@@ -4,13 +4,17 @@ from pytensor import Variable, shared
 from pytensor import tensor as pt
 from pytensor.graph import Apply, ancestors, graph_inputs
 from pytensor.graph.traversal import (
+    apply_ancestors,
     apply_depends_on,
     explicit_graph_inputs,
     general_toposort,
     get_var_by_name,
     io_toposort,
     orphans_between,
+    toposort,
+    toposort_with_orderings,
     truncated_graph_inputs,
+    variable_ancestors,
     variable_depends_on,
     vars_between,
     walk,
@@ -36,23 +40,17 @@ class TestToposort:
         o2 = MyOp(o, r5)
         o2.name = "o2"
 
-        clients = {}
-        res = general_toposort([o2], self.prenode, clients=clients)
-
-        assert clients == {
-            o2.owner: [o2],
-            o: [o2.owner],
-            r5: [o2.owner],
-            o.owner: [o],
-            r1: [o.owner],
-            r2: [o.owner],
-        }
+        res = general_toposort([o2], self.prenode)
         assert res == [r5, r2, r1, o.owner, o, o2.owner, o2]
 
-        with pytest.raises(ValueError):
-            general_toposort(
-                [o2], self.prenode, compute_deps_cache=lambda x: None, deps_cache=None
-            )
+        def circular_dependency(obj):
+            if obj is o:
+                # o2 depends on o, so o cannot depend on o2
+                return [o2, *self.prenode(obj)]
+            return self.prenode(obj)
+
+        with pytest.raises(ValueError, match="graph contains cycles"):
+            general_toposort([o2], circular_dependency)
 
         res = io_toposort([r5], [o2])
         assert res == [o.owner, o2.owner]
@@ -181,16 +179,16 @@ def test_ancestors():
 
     res = ancestors([o2], blockers=None)
     res_list = list(res)
-    assert res_list == [o2, r3, o1, r1, r2]
+    assert res_list == [o2, o1, r2, r1, r3]
 
     res = ancestors([o2], blockers=None)
-    assert r3 in res
+    assert o1 in res
     res_list = list(res)
-    assert res_list == [o1, r1, r2]
+    assert res_list == [r2, r1, r3]
 
     res = ancestors([o2], blockers=[o1])
     res_list = list(res)
-    assert res_list == [o2, r3, o1]
+    assert res_list == [o2, o1, r3]
 
 
 def test_graph_inputs():
@@ -202,7 +200,7 @@ def test_graph_inputs():
 
     res = graph_inputs([o2], blockers=None)
     res_list = list(res)
-    assert res_list == [r3, r1, r2]
+    assert res_list == [r2, r1, r3]
 
 
 def test_explicit_graph_inputs():
@@ -231,7 +229,7 @@ def test_variables_and_orphans():
 
     vars_res_list = list(vars_res)
     orphans_res_list = list(orphans_res)
-    assert vars_res_list == [o2, o1, r3, r2, r1]
+    assert vars_res_list == [o2, o1, r2, r1, r3]
     assert orphans_res_list == [r3]
 
 
@@ -408,3 +406,37 @@ def test_get_var_by_name():
 
     exp_res = igo.fgraph.outputs[0]
     assert res == exp_res
+
+
+@pytest.mark.parametrize(
+    "func",
+    [
+        lambda x: all(variable_ancestors([x])),
+        lambda x: all(variable_ancestors([x], blockers=[x.clone()])),
+        lambda x: all(apply_ancestors([x])),
+        lambda x: all(apply_ancestors([x], blockers=[x.clone()])),
+        lambda x: all(toposort([x])),
+        lambda x: all(toposort([x], blockers=[x.clone()])),
+        lambda x: all(toposort_with_orderings([x], orderings={x: []})),
+        lambda x: all(
+            toposort_with_orderings([x], blockers=[x.clone()], orderings={x: []})
+        ),
+    ],
+    ids=[
+        "variable_ancestors",
+        "variable_ancestors_with_blockers",
+        "apply_ancestors",
+        "apply_ancestors_with_blockers)",
+        "toposort",
+        "toposort_with_blockers",
+        "toposort_with_orderings",
+        "toposort_with_orderings_and_blockers",
+    ],
+)
+def test_traversal_benchmark(func, benchmark):
+    r1 = MyVariable(1)
+    out = r1
+    for i in range(50):
+        out = MyOp(out, out)
+
+    benchmark(func, out)

tests/link/numba/test_scan.py

+from itertools import chain
+
 import numpy as np
 import pytest
 
@@ -490,6 +492,7 @@ def test_inplace_taps(n_steps_constant):
         if isinstance(node.op, Scan)
     ]
 
+    # Collect inner inputs we expect to be destroyed by the step function
     # Scan reorders inputs internally, so we need to check its ordering
     inner_inps = scan_op.fgraph.inputs
     mit_sot_inps = scan_op.inner_mitsot(inner_inps)
@@ -501,28 +504,22 @@ def test_inplace_taps(n_steps_constant):
     ]
     [sit_sot_inp] = scan_op.inner_sitsot(inner_inps)
 
-    inner_outs = scan_op.fgraph.outputs
-    mit_sot_outs = scan_op.inner_mitsot_outs(inner_outs)
-    [sit_sot_out] = scan_op.inner_sitsot_outs(inner_outs)
-    [nit_sot_out] = scan_op.inner_nitsot_outs(inner_outs)
+    destroyed_inputs = []
+    for inner_out in scan_op.fgraph.outputs:
+        node = inner_out.owner
+        dm = node.op.destroy_map
+        if dm:
+            destroyed_inputs.extend(
+                node.inputs[idx] for idx in chain.from_iterable(dm.values())
+            )
 
     if n_steps_constant:
-        assert mit_sot_outs[0].owner.op.destroy_map == {
-            0: [mit_sot_outs[0].owner.inputs.index(oldest_mit_sot_inps[0])]
-        }
-        assert mit_sot_outs[1].owner.op.destroy_map == {
-            0: [mit_sot_outs[1].owner.inputs.index(oldest_mit_sot_inps[1])]
-        }
-        assert sit_sot_out.owner.op.destroy_map == {
-            0: [sit_sot_out.owner.inputs.index(sit_sot_inp)]
-        }
+        assert len(destroyed_inputs) == 3
+        assert set(destroyed_inputs) == {*oldest_mit_sot_inps, sit_sot_inp}
     else:
         # This is not a feature, but a current limitation
         # https://github.com/pymc-devs/pytensor/issues/1283
-        assert mit_sot_outs[0].owner.op.destroy_map == {}
-        assert mit_sot_outs[1].owner.op.destroy_map == {}
-        assert sit_sot_out.owner.op.destroy_map == {}
-    assert nit_sot_out.owner.op.destroy_map == {}
+        assert not destroyed_inputs
 
 
 @pytest.mark.parametrize(

tests/tensor/test_math_scipy.py

@@ -1170,8 +1170,8 @@ class TestHyp2F1Grad:
                 if isinstance(node.op, Elemwise)
                 and isinstance(node.op.scalar_op, ScalarLoop)
             ]
-            assert scalar_loop_op1.nin == 10 + 3 * 2  # wrt=[0, 1]
-            assert scalar_loop_op2.nin == 10 + 3 * 1  # wrt=[2]
+            assert scalar_loop_op1.nin == 10 + 3 * 1  # wrt=[2]
+            assert scalar_loop_op2.nin == 10 + 3 * 2  # wrt=[0, 1]
         else:
             [scalar_loop_op] = [
                 node.op.scalar_op