Fixed bug where coef() didn't would error if used on a brulee_logistic_reg() that was trained with a recipe (#67)

* extract rows instead of columns in coef.brulee_logistic_reg()

* add news

* add test

---------

Co-authored-by: Max Kuhn <[email protected]>

Author: EmilHvitfeldt

NEWS.md

@@ -1,7 +1,10 @@
 # brulee (development version)
 
+* Fixed bug where `coef()` didn't would error if used on a `brulee_logistic_reg()` that was trained with a recipe. (#66)
+
 * Fixed a bug where SGD always being used as the optimizer (#61). 
 
+
 # brulee 0.2.0
 
 * Several learning rate schedulers were added to the modeling functions (#12).

R/coef.R

@@ -58,7 +58,7 @@ brulee_coefs <- function(object, epoch = NULL, ...) {
 #' @export
 coef.brulee_logistic_reg <- function(object, epoch = NULL, ...) {
  network_params <- brulee_coefs(object, epoch)
- slopes <- network_params$fc1.weight[,2] - network_params$fc1.weight[,1]
+ slopes <- network_params$fc1.weight[2, ] - network_params$fc1.weight[1, ]
  int <- network_params$fc1.bias[2] - network_params$fc1.bias[1]
  param <- c(int, slopes)
  names(param) <- c("(Intercept)", object$dims$features)

tests/testthat/test-logistic_reg-fit.R

@@ -112,6 +112,35 @@ test_that("basic logistic regression SGD", {
  expect_true(bin_brier_sgd$.estimate < (1 - 1/num_class)^2)
 })
 
+test_that("coef works when recipes are used", {
+ skip_if_not(torch::torch_is_installed())
+ skip_if_not_installed("modeldata")
+ skip_if_not_installed("recipes")
+ skip_if(packageVersion("rlang") < "1.0.0")
+ skip_on_os(c("windows", "linux", "solaris"))
+
+  data("lending_club", package = "modeldata")
+  lending_club <- head(lending_club, 1000)
+
+  rec <-
+   recipes::recipe(Class ~ revol_util + open_il_24m + emp_length,
+                   data = lending_club) %>%
+   recipes::step_dummy(emp_length, one_hot = TRUE) %>%
+   recipes::step_normalize(recipes::all_predictors())
+
+  fit_rec <- brulee_logistic_reg(rec, lending_club, epochs = 10L)
+
+  coefs <- coef(fit_rec)
+  expect_true(all(is.numeric(coefs)))
+  expect_identical(
+   names(coefs),
+   c(
+    "(Intercept)", "revol_util", "open_il_24m",
+    paste0("emp_length_", levels(lending_club$emp_length))
+   )
+  )
+})
+
 
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