Combine HRF Basis with Coefficients

Create a new HRF by linearly weighting the basis functions of an existing HRF. This is useful for turning estimated basis coefficients into a single functional HRF.

S3 method for `HRF` objects that returns a matrix mapping basis coefficients to sampled HRF values at the provided time grid. For single-basis HRFs, this returns a one-column matrix. For multi-basis HRFs (e.g., SPMG2/SPMG3, FIR, B-spline), this returns a matrix with one column per basis function.

Usage

reconstruction_matrix(hrf, sframe, ...)

# S3 method for class 'HRF'
reconstruction_matrix(hrf, sframe, ...)

Arguments

hrf

An object of class `HRF`.

sframe

A numeric vector of times, or a `sampling_frame` object from which times are extracted via `samples()`.

...

Additional arguments passed to `samples()` when `sframe` is a `sampling_frame`, and to `evaluate()` for HRF evaluation.

Value

A numeric matrix with one column per basis function.

A numeric matrix of dimension `length(times) x nbasis(hrf)`.

Details

Reconstruction matrix for an HRF basis

Returns a matrix \(\Phi\) that converts basis coefficients into a sampled HRF shape.

Examples

# Create reconstruction matrix for basis functions
hrf <- HRF_SPMG2  # 2-basis HRF
times <- seq(0, 20, by = 0.5)
rmat <- reconstruction_matrix(hrf, times)
dim(rmat)  # Shows dimensions
#> [1] 41  2