Repeat

class braintools.cogtask.Repeat(phase, count, name=None)

Repeat a phase N times.

Created via: phase * N

During execution, the loop iteration is exposed under both ctx['repeat_index'] and ctx['_repeat_stack'] (a list, supporting nested Repeat). Restoration on exit keeps the outer index intact.

Examples

>>> # Repeat stimulus 5 times
>>> repeated = Stimulus(100*u.ms) * 5

>>> # In a sequence
>>> phases = Fixation(100*u.ms) >> (Stimulus(50*u.ms) * 10) >> Response(100*u.ms)

children()

Return the immediate child phases of a compound phase.

Leaf phases return []. Subclasses like Sequence, Repeat, Parallel, If, Switch, While override this so that the Task can traverse the whole tree to bind features.

Return type:

List[Phase]

encode_inputs(ctx)

Fill ctx.inputs[phase_start:phase_end] with input encoding.

Called once per phase after duration is determined. Must modify ctx.inputs in-place.

Parameters:

ctx (Context) – Context with input buffer and trial state.

Return type:

None

encode_outputs(ctx)

Fill ctx.outputs[phase_start:phase_end] with target encoding.

Called once per phase after duration is determined. Must modify ctx.outputs in-place.

Parameters:

ctx (Context) – Context with output buffer and trial state.

Return type:

None

execute(ctx)

Execute the phase count times with a scoped repeat index.

Return type:

None

get_duration(ctx)

Get total duration by multiplying single phase duration.

Return type:

int

max_steps(ctx)

Static upper bound on this phase’s length in timesteps.

Must return a Python int with no dependence on traced values. Used by Task in variable-length mode to size shape-stable buffers. The default delegates to get_duration which is correct for fixed-duration phases. Variable-duration phases (e.g. those wrapping TruncExp/UniformDuration) override this to return the truncation upper bound divided by ctx.dt.

Parameters:

ctx (Context) – A stub or trial context providing ctx.dt. The default implementation does not read ctx.rng or trial state.

Returns:

Upper bound on number of timesteps for this phase.

Return type:

int

step_count(ctx)

Traced actual length of this phase in timesteps.

Returns a jax.Array int32 scalar. May depend on ctx[...] values populated by trial_init. Must satisfy 0 <= step_count(ctx) <= max_steps(ctx) for every trial.

The default returns a static value equal to get_duration; that is correct for any phase whose actual length matches its upper bound. Variable-duration phases override this to compute the traced length from ctx state without any int(...) cast.

Return type:

Array