pre-extract workflow parameter set

[simonpcouch]

The extraction of parameter sets from workflows is now much quicker, though it still happens for every resample. In the boilerplate mtcars bootstrap fit, it accounts for ~13% of total evaluation time with main dev. Since the workflow is not an index of the loop over tune_grid_loop_iter, we can pre-compute the parameter set and pass it as an argument.

With main dev:

library(tidymodels)

set.seed(1)

bench::mark(
  total = fit_resamples(linear_reg(), mpg ~ ., bootstraps(mtcars, 100)),
  iterations = 5
)
#> # A tibble: 1 × 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 total         2.71s    2.73s     0.363    46.3MB     6.96

^{Created on 2023-03-17 with reprex v2.0.2}

With this PR:

#> # A tibble: 1 × 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 total         2.35s    2.39s     0.415    43.5MB     7.40

^{Created on 2023-03-17 with reprex v2.0.2}

[EmilHvitfeldt]

Looks good!

one question: Why did you set params = hardhat::extract_parameter_set_dials(workflow) as the argument in tune_grid_loop_iter() but params as the argument in tune_grid_loop_iter_safely()?

[simonpcouch]

Not for good reason. :) I had thought some functions in finetune hooked into tune_grid_loop_iter() at a lower level than they do and thus would not have passed that argument, but they use the exported interface. Removing that default!

[github-actions]

This pull request has been automatically locked. If you believe you have found a related problem, please file a new issue (with a reprex: https://reprex.tidyverse.org) and link to this issue.