Realise per-trial event durations onto the stimuli table

An event may declare a duration that varies from trial to trial, either read from an item column or drawn from a range. A drawn value is a pure function of the keyed hash, so both engines realise the same milliseconds, and it is written into the stimuli table as well as the generated script, because timing that varies is a variable the analysis needs, not presentation detail.

Usage

resolve_trial_timing(stimuli, design, schema)

Arguments

stimuli

A counterbalanced stimuli data frame.

design

A parsed design configuration.

schema

The parsed global schema (provides the seed).

Value

stimuli with one integer column per jittered event, and every column of fractional milliseconds rounded. Each column rounded is recorded in the "duration_rounding" attribute, as one list(event, column, n_rounded) entry, which run_pipeline() writes into the run log.

Details

Every value read from a column must be a finite number of milliseconds, not negative. The first that is not, a blank cell included, is refused, naming the column and the trial's set and condition. A blank or negative value used to reach the experiments, where OpenSesame and PsychoPy stopped at the blank and jsPsych ended the trial at once. When a column holds fractional milliseconds, each of its values is rounded once with the rounder both engines share and written back, so the stimuli, the loop tables and every target carry the same whole milliseconds. A column of whole numbers is left as it is.