tests/testthat/test_poisson_regression.R

In xgboost: Extreme Gradient Boosting

context('Test Poisson regression model')

require(xgboost)
set.seed(1994)

test_that("Poisson regression works", {
  data(mtcars)
  bst <- xgboost(
    data = as.matrix(mtcars[, -11]), label = mtcars[, 11],
    objective = 'count:poisson', nrounds = 10, verbose = 0, nthread = 2
  )
  expect_equal(class(bst), "xgb.Booster")
  pred <- predict(bst, as.matrix(mtcars[, -11]))
  expect_equal(length(pred), 32)
  expect_lt(sqrt(mean((pred - mtcars[, 11])^2)), 1.2)
})