Nested cross-validation with spatial block CV and cluster CV

[gregor-fausto]

I'm setting up a nested cross-validation using spatial block cross-validation for outer folds and cluster cross-validation for inner folds. Interaction between these two types of cross-validations gives me the following error:

library(spatialsample)
library(rsample)
folds <- spatialsample::spatial_block_cv(boston_canopy, v = 3)
rsample::nested_cv(boston_canopy, outside = folds, inside = rsample::clustering_cv(v = 3, repeats = 1, vars = c('mean_temp','mean_heat_index_morning')))
#> Error in `map()`:
#> ℹ In index: 1.
#> Caused by error in `dist()`:
#> ! 'list' object cannot be coerced to type 'double'

The behavior that I'm trying to achieve is shown here:

library(spatialsample)
library(rsample)
library(sf)
#> Linking to GEOS 3.11.0, GDAL 3.5.3, PROJ 9.1.0; sf_use_s2() is TRUE
folds <- spatialsample::spatial_block_cv(boston_canopy, v = 3)
tmp<-list()
for(j in 1:nrow(folds)){
  x<-rsample::analysis(folds$splits[[j]]) %>% sf::st_drop_geometry()
  tmp[[j]] <- rsample::clustering_cv(data=x, v = 3, repeats = 1, vars = c('mean_temp','mean_heat_index_morning'))
}
folds$inner_resamples <- tmp
folds
#> #  3-fold spatial block cross-validation 
#> # A tibble: 3 × 3
#>   splits            id    inner_resamples   
#>   <list>            <chr> <list>            
#> 1 <split [458/224]> Fold1 <clt_fold [3 × 2]>
#> 2 <split [469/213]> Fold2 <clt_fold [3 × 2]>
#> 3 <split [437/245]> Fold3 <clt_fold [3 × 2]>

This example uses data from the spatialsample package. I've opened the issue in rsample because the error message seems to be related to how rsample::nested_cv interacts with the output of spatial_block_cv.