tests/testthat/test_psp_R.R

In psp: Parameter Space Partitioning MCMC for Global Model Evaluation

euclidean <- function(a, b) sqrt(sum((a - b)^2))

# define center points for the 10 regions in a two-dimensional space
positions <- NULL
# set seed
set.seed(7624)
for (i in seq_len(5)) positions <- cbind(positions, sample(500, 100))

## calculates distances and gives a non-sensical inequality matrix
model <- function(par, legacy = FALSE) {
  areas <- NULL
  for (i in seq_along(par)) {
    range <- c(1, 0)
    if (i %% 2 == 0) {
      range <- c(0, 1)
    }
    areas <- cbind(areas, seq(range[1], range[2], length.out = 500)[positions[, i]])
  }
  distances <- apply(areas, 1, euclidean, b = par)

  if (legacy) {
    out <- as.character(which.min(distances))
  } else {
    out <- matrix(which.min(distances), nrow = 2, ncol = 2)
  }
  return(out)
}

# run Parameter Space Partitioning
out <- suppressWarnings(
  psp_global(model, psp_control(
    lower = rep(0, 5),
    upper = rep(1, 5),
    init = rep(0.5, 5),
    radius = rep(0.5, 5),
    pop = 300,
    parallel = FALSE,
    iterations = 100
  ), legacy = TRUE)
)

test_that("PSP finds all 100 regions in a 5 parameter model", {
  expect_equal(length(out[[2]]), 100)
})