generate_dlm_dataset: generates Distributed Lag Model or polynomial function effect
In apeterson91/STAPSimulations: Recreates Simulations in Peterson et al. manuscript

generates Distributed Lag Model or polynomial function effect

generate_dlm_dataset(seed = NULL, num_subj = 100, num_dists = 30,
  bef_xlim = c(-1, 1), bef_ylim = c(-1, 1), subj_xlim = c(-1, 1),
  subj_ylim = c(-1, 1), alpha = 25, delta = -2.3, beta = 0.1,
  sigma = 1, K = function(x) {     (x <= 1.2) * 1 })

`seed`	an integer for set.seed()
`num_subj`	number of subjects to simulate
`num_dists`	number of distances/subject to simulate
`alpha`	true intercept value
`delta`	confounder effect
`beta`	true bef effect
`theta`	true spatial scale
`W`	weight function