Glossary

Public Terms

These terms describe tracing, transformations, and execution:

Term	Definition
batch	IR transform to vectorize over a selection of input leaves.
checkpoint	A primitive that labels an intermediate value with a key and collection. It is transparent unless collect or inject is active.
collect	Context manager to capture checkpointed values during IR execution.
Collection	A namespace used by checkpoints, collect, and inject to decide which values belong together.
Cotangent	Feedback flowing backward through a pullback. The registered type determines its meaning, such as text feedback for strings or numerical gradients for floats.
Custom rule	A rule to be applied to the pushforward, pullback, or batch of a function boundary marked with custom.
dce	IR transform: dead code elimination, removes equations that are not required to produce selected outputs.
Schema description	Generation guidance, can be applied to a spec with desc= or spec @ description.
Dynamic argument	An input leaf that will be replaced with a placeholder at trace time and supplied at execution time.
Execute	Phase where the IR is run with concrete inputs by calling .call(...) or .acall(...).
factor	Primitive: multiply the current path weight by a scalar. Neutral when executing normally, but used to produce weight results.
fixpoint	A higher-order control-flow primitive that repeatedly applies a traced (State, Theta) -> State step until the state is stable or max_iters is reached.
fold	Context manager to evaluate calls to foldable primitives immediately during tracing and insert the result as a literal.
inject	A context manager that substitutes checkpointed values from a provided dictionary during execution.
Schema instance	A container of context and specs. The structure of the container determines the shape of the output when calling the model.
Intercept	Runtime hook for intercepting checkpointed values. Used by collect to capture values and inject to replace values.
IR	The intermediate representation produced by trace; it contains input variables, equations, and outputs.
client	Context manager to select a client to use for fill.
memoize	A context manager that caches primitive results within its block. During tracing, it can deduplicate identical primitive calls.
pullback	IR transform to propagate cotangents from outputs to inputs.
pushforward	IR transform to propagate tangents from inputs to outputs.
Pytree	A nested container/leaf structure that autoform can walk. Registered dataclasses can be pytrees.
PYTREE_NAMESPACE	Optree namespace reserved for use by autoform when registering user pytrees.
sched	IR transform to group equations that can be executed concurrently using async.
Schema	A pytree of specifications such as Str, Float, and Enum, used by fill to describe generated values.
Static argument	An input leaf that will be fixed by trace. static is a bool pytree that should match the structure of the positional inputs to trace.
tag value	Hashable metadata that can be attached to equations during tracing.
tag	Context manager to apply one or more tags to all equations produced within the block.
Trace	The phase that runs a Python function once with placeholders and records autoform primitive calls as IR equations.
Transform	A function that consumes an IR and returns another IR. Current transforms include: batch, pushforward, pullback, sched, dce, and weight.
weight	An IR transform that returns (output, path_weight) for one concrete path.

Internal IR Machinery

These names may be useful when inspecting internals and debugging transforms, but these names are not part of the normal user surface.

Term	Definition
Eqn	A single application of a primitive in the IR.
Var	Typed placeholder for a value that will be supplied when running the IR.
Prim	A named primitive operation used as the dispatch key for execution and transform rules.
TraceBox	The internal wrapper used by the trace interpreter to carry a Var through Python code.
Tracer	The trace-time interpreter machinery that records primitive calls instead of executing the calls normally.
walk	The manual IR stepping interface used by execution internals and advanced debugging code. Manual Execution describes the stepping interface.