pulsatrix::ComputationGraph Class Reference

Owns every Node in a computation graph and exposes read access for graph-walking code (autograd's backward pass, Phase 2+ explainers). More...

#include <computation_graph.hpp>

Public Member Functions
NodeId	add_node (OpType op_type, Shape shape, std::optional< std::string > label=std::nullopt, std::vector< NodeId > parent_ids={})
	Adds a node to the graph and wires it to its parents.
const Node &	node (NodeId id) const
	Looks up a node by id.
size_t	node_count () const
	Number of nodes currently in the graph.
std::vector< NodeId >	nodes_by_op_type (OpType op_type) const
	Finds every node with the given op type.
std::vector< NodeId >	topological_order () const
	Returns every node id in a valid topological order (every node after all its parents).

Detailed Description

Owns every Node in a computation graph and exposes read access for graph-walking code (autograd's backward pass, Phase 2+ explainers).

Note

This class exposes no method that removes a node or clears the graph. That is deliberate, not an oversight – the charter's central Phase 0 requirement is that the graph survives past the backward pass (Mission 3 exercises this directly). Nothing in this codebase should be able to silently discard graph structure.

Member Function Documentation

add_node()

NodeId pulsatrix::ComputationGraph::add_node	(	OpType	op_type,
		Shape	shape,
		std::optional< std::string >	label = std::nullopt,
		std::vector< NodeId >	parent_ids = {}
	)

Adds a node to the graph and wires it to its parents.

Parameters

op_type	The operation category this node represents.
shape	This node's output shape.
label	Optional human-readable label.
parent_ids	Ids of this node's parents. Every id must already exist in the graph (i.e. refer to a node added by an earlier call) – this constraint is what guarantees insertion order is already a valid topological order.

Returns

The new node's id.

node()

const Node & pulsatrix::ComputationGraph::node

(

NodeId

id

)

const

Looks up a node by id.

Parameters

id	Node id, must be < node_count().

Returns

The node.

node_count()

size_t pulsatrix::ComputationGraph::node_count ( ) const

inline

Number of nodes currently in the graph.

nodes_by_op_type()

std::vector< NodeId > pulsatrix::ComputationGraph::nodes_by_op_type

(

OpType

op_type

)

const

Finds every node with the given op type.

Parameters

op_type

Op type to match.

Returns

Ids of matching nodes, in insertion order. Empty if none match.

Note

This is the op-type-tagging query mechanism from charter Part 2 SS3 – e.g. Grad-CAM finding "the last conv layer" queries this, never by layer name.

topological_order()

std::vector< NodeId > pulsatrix::ComputationGraph::topological_order

(

)

const

Returns every node id in a valid topological order (every node after all its parents).

Returns

Node ids in topological order.

Note

Simply returns insertion order – add_node()'s constraint that parent_ids must already exist in the graph guarantees insertion order is already topological. If a future relaxation of that constraint is ever considered, this method's implementation would need to change to an explicit sort; it does not today.

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The documentation for this class was generated from the following file:

• include/pulsatrix/computation_graph.hpp