Package a base mask into a contrast object — contrast_from

Drives the unified post-processing pipeline: expands the base mask across basis functions (when applicable), applies basis filtering, attaches the standard contrast list class, and returns an object compatible with downstream contrast_weights.event_model().

Usage

contrast_from_mask(mask, spec, term, classes = character())

Arguments

mask: Output of contrast_mask() (or compatible list).
spec: The originating contrast spec (stored on the result).
term: The event_term the contrast is being computed against.
classes: Character vector of extra S3 classes prepended to the default c("cell_contrast", "contrast", "list").

Value

A contrast object.

Details

Custom contrast types implement contrast_mask() and call this driver.

Examples

term <- event_term(
  list(condition = factor(c("A", "B"))),
  onsets = c(0, 2),
  blockids = c(1, 1)
)
condition_names <- conditions(term, drop.empty = FALSE)
weights <- matrix(
  c(1, -1), ncol = 1,
  dimnames = list(condition_names, "A-B")
)
spec <- structure(
  list(name = "A-B", basis = NULL, basis_weights = NULL),
  class = c("example_contrast_spec", "contrast_spec", "list")
)
result <- contrast_from_mask(
  list(weights = weights, condnames = condition_names),
  spec,
  term
)
result$weights
#>             A-B
#> condition.A   1
#> condition.B  -1