Create an HRF from a basis specification

`make_hrf` resolves a basis specification to an `HRF` object and applies an optional temporal lag. The basis may be given as the name of a built-in HRF, as a generating function, or as an existing `HRF` object.

Usage

make_hrf(basis, lag, nbasis = NULL)

Arguments

basis

Character name of a built-in HRF, a function that generates HRF values, or an object of class `HRF`.

lag

Numeric scalar giving the shift in seconds applied to the HRF.

nbasis

Number of basis functions. `NULL` (the default) gives a basis-set name such as `"bspline"` or `"fir"` the default size used by [getHRF()], and a plain function as many basis functions as the columns it returns. Ignored for fixed HRFs such as `"spmg1"` or an `HRF` object.

Value

An object of class `HRF` representing the lagged basis.

Examples

# Canonical SPM HRF delayed by 2 seconds
h <- make_hrf("spmg1", lag = 2)
h(0:5)
#> [1] 0.000000000 0.000000000 0.000000000 0.003065662 0.036089408 0.100818722