generate_nhpp_dataset: generates nonhomogenous poisson process data
In apeterson91/STAPSimulations: Recreates Simulations in Peterson et al. manuscript

generates nonhomogenous poisson process data

generate_nhpp_dataset(seed = NULL, num_subj_realizations = 10L,
  num_dist_realizations = 4L, Lambda_xy = function(x, y) {     (3 - x^2
  - y^2) }, bef_xlim = c(-1, 1), bef_ylim = c(-1, 1),
  subj_xlim = c(-1, 1), subj_ylim = c(-1, 1), alpha = 23,
  delta = -2.2, beta = 0.75, theta = 0.5, sigma = 1,
  K = function(x) exp(-x))

`seed`	an integer for set.seed()
`num_subj_realizations`	number of subjects position processes to simulate
`num_dist_realizations`	number of bef processes to simulate
`bef_xlim`	x coordinate bounds from which to simulate befs
`bef_ylim`	y coordinate bounds from which to simulate bef positions
`subj_xlim`	x coordinate bounds from which to simulate subject positions
`subj_ylim`	y coordinate bounds from which to simulate subject positions
`alpha`	true intercept value
`delta`	confounder effect
`beta`	true bef effect
`theta`	true spatial scale
`K`	exposure function
`inten`	intensity function for nhpp as a function of spatial coords (x,y)