diff --git a/b_asic/operation.py b/b_asic/operation.py
index a0d0f48a1f7429ce0d393ad4e93ef24c84914f7b..bb66e26b30a4a14b116800300d5a00d0855945f2 100644
--- a/b_asic/operation.py
+++ b/b_asic/operation.py
@@ -180,6 +180,11 @@ class Operation(GraphComponent, SignalSourceProvider):
"""
raise NotImplementedError
+ @abstractmethod
+ def inputs_required_for_output(self, output_index: int) -> Iterable[int]:
+ """Get the input indices of all inputs in this operation whose values are required in order to evalueate the output at the given output index."""
+ raise NotImplementedError
+
class AbstractOperation(Operation, AbstractGraphComponent):
"""Generic abstract operation class which most implementations will derive from.
@@ -340,6 +345,11 @@ class AbstractOperation(Operation, AbstractGraphComponent):
pass
return [self]
+ def inputs_required_for_output(self, output_index: int) -> Iterable[int]:
+ if output_index < 0 or output_index >= self.output_count:
+ raise IndexError(f"Output index out of range (expected 0-{self.output_count - 1}, got {output_index})")
+ return [i for i in range(self.input_count)] # By default, assume each output depends on all inputs.
+
@property
def neighbors(self) -> Iterable[GraphComponent]:
return list(self.input_signals) + list(self.output_signals)
diff --git a/b_asic/signal_flow_graph.py b/b_asic/signal_flow_graph.py
index d311bfacb69878c76d03b4194c5cf24a54e4f79c..bcfc9eebd7599128a92c83beafa64209fce6e43a 100644
--- a/b_asic/signal_flow_graph.py
+++ b/b_asic/signal_flow_graph.py
@@ -3,7 +3,7 @@ B-ASIC Signal Flow Graph Module.
TODO: More info.
"""
-from typing import List, Iterable, Sequence, Dict, Optional, DefaultDict, Set
+from typing import List, Iterable, Sequence, Dict, Optional, DefaultDict, MutableSet
from numbers import Number
from collections import defaultdict, deque
@@ -45,7 +45,7 @@ class SFG(AbstractOperation):
_graph_id_generator: GraphIDGenerator
_input_operations: List[Input]
_output_operations: List[Output]
- _original_components_to_new: Set[GraphComponent]
+ _original_components_to_new: MutableSet[GraphComponent]
_original_input_signals_to_indices: Dict[Signal, int]
_original_output_signals_to_indices: Dict[Signal, int]
@@ -155,6 +155,9 @@ class SFG(AbstractOperation):
raise ValueError(f"Output signal #{output_index} is missing source in SFG")
if signal.source.operation not in self._original_components_to_new:
self._add_operation_connected_tree_copy(signal.source.operation)
+
+ # Find dependencies.
+
def __str__(self) -> str:
"""Get a string representation of this SFG."""
@@ -233,6 +236,11 @@ class SFG(AbstractOperation):
def split(self) -> Iterable[Operation]:
return self.operations
+
+ def inputs_required_for_output(self, output_index: int) -> Iterable[int]:
+ if output_index < 0 or output_index >= self.output_count:
+ raise IndexError(f"Output index out of range (expected 0-{self.output_count - 1}, got {output_index})")
+ return self._inputs_required_for_source(self._output_operations[output_index].input(0).signals[0].source, set())
def copy_component(self, *args, **kwargs) -> GraphComponent:
return super().copy_component(*args, **kwargs, inputs = self._input_operations, outputs = self._output_operations,
@@ -423,3 +431,18 @@ class SFG(AbstractOperation):
value = src.operation.evaluate_output(src.index, input_values, results, registers, src_prefix)
results[key] = value
return value
+
+ def _inputs_required_for_source(self, src: OutputPort, visited: MutableSet[Operation]) -> Sequence[bool]:
+ if src.operation in visited:
+ return []
+ visited.add(src.operation)
+
+ if isinstance(src.operation, Input):
+ for i, input_operation in enumerate(self._input_operations):
+ if input_operation is src.operation:
+ return [i]
+
+ input_indices = []
+ for i in src.operation.inputs_required_for_output(src.index):
+ input_indices.extend(self._inputs_required_for_source(src.operation.input(i).signals[0].source, visited))
+ return input_indices
diff --git a/test/fixtures/signal_flow_graph.py b/test/fixtures/signal_flow_graph.py
index 7a8c4a73a62cf248c98993f5cf8c831bc986b8a7..5a0ef25b94cec8e3fad9275cccf97882703de330 100644
--- a/test/fixtures/signal_flow_graph.py
+++ b/test/fixtures/signal_flow_graph.py
@@ -29,6 +29,33 @@ def sfg_two_inputs_two_outputs():
out2 = Output(add2)
return SFG(inputs = [in1, in2], outputs = [out1, out2])
+@pytest.fixture
+def sfg_two_inputs_two_outputs_independent():
+ """Valid SFG with two inputs and two outputs, where the first output only depends
+ on the first input and the second output only depends on the second input.
+ . .
+ in1-------------------->out1
+ . .
+ . .
+ . c1--+ .
+ . | .
+ . v .
+ in2------+ add1---->out2
+ . | ^ .
+ . | | .
+ . +------+ .
+ . .
+ out1 = in1
+ out2 = in2 + 3
+ """
+ in1 = Input()
+ in2 = Input()
+ c1 = Constant(3)
+ add1 = in2 + c1
+ out1 = Output(in1)
+ out2 = Output(add1)
+ return SFG(inputs = [in1, in2], outputs = [out1, out2])
+
@pytest.fixture
def sfg_nested():
"""Valid SFG with two inputs and one output.
diff --git a/test/test_depends.py b/test/test_depends.py
new file mode 100644
index 0000000000000000000000000000000000000000..e26911054a9604db2f08998f6ecfccd81a012e5a
--- /dev/null
+++ b/test/test_depends.py
@@ -0,0 +1,19 @@
+from b_asic import Addition, Butterfly
+
+class TestDepends:
+ def test_depends_addition(self):
+ add1 = Addition()
+ assert set(add1.inputs_required_for_output(0)) == {0, 1}
+
+ def test_depends_butterfly(self):
+ bfly1 = Butterfly()
+ assert set(bfly1.inputs_required_for_output(0)) == {0, 1}
+ assert set(bfly1.inputs_required_for_output(1)) == {0, 1}
+
+ def test_depends_sfg(self, sfg_two_inputs_two_outputs):
+ assert set(sfg_two_inputs_two_outputs.inputs_required_for_output(0)) == {0, 1}
+ assert set(sfg_two_inputs_two_outputs.inputs_required_for_output(1)) == {0, 1}
+
+ def test_depends_sfg_independent(self, sfg_two_inputs_two_outputs_independent):
+ assert set(sfg_two_inputs_two_outputs_independent.inputs_required_for_output(0)) == {0}
+ assert set(sfg_two_inputs_two_outputs_independent.inputs_required_for_output(1)) == {1}
\ No newline at end of file