Error(s) in re-building vignettes:
--- re-building 'choice-of-SEL-weights.Rmd' using rmarkdown
Warning in hook_png(..., cmd = "pngquant", post_process = function(x) { :
  cannot find pngquant; please install and put it in PATH
Warning in hook_png(..., cmd = "pngquant", post_process = function(x) { :
  cannot find pngquant; please install and put it in PATH
Warning in hook_png(..., cmd = "pngquant", post_process = function(x) { :
  cannot find pngquant; please install and put it in PATH

Quitting from choice-of-SEL-weights.Rmd:138-150 [unnamed-chunk-4]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<error/rlang_error>
Error in `[.data.table`:
! attempt access index 2/2 in VECTOR_ELT
---
Backtrace:
    ▆
 1. └─smoothemplik::kernelSmooth(...)
 2.   └─smoothemplik::prepareKernel(...)
 3.     └─smoothemplik:::.deduplicate(xy)
 4.       ├─x[, `:=`(`(id)` = .GRP, `(count)` = .N), by = names(x)]
 5.       └─data.table:::`[.data.table`(...)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Error: processing vignette 'choice-of-SEL-weights.Rmd' failed with diagnostics:
attempt access index 2/2 in VECTOR_ELT
--- failed re-building 'choice-of-SEL-weights.Rmd'

--- re-building 'non-parametric-rcpp.Rmd' using rmarkdown
Warning in hook_png(..., cmd = "pngquant", post_process = function(x) { :
  cannot find pngquant; please install and put it in PATH
Warning in hook_png(..., cmd = "pngquant", post_process = function(x) { :
  cannot find pngquant; please install and put it in PATH
Warning in hook_png(..., cmd = "pngquant", post_process = function(x) { :
  cannot find pngquant; please install and put it in PATH
Warning in hook_png(..., cmd = "pngquant", post_process = function(x) { :
  cannot find pngquant; please install and put it in PATH
Warning in hook_png(..., cmd = "pngquant", post_process = function(x) { :
  cannot find pngquant; please install and put it in PATH
Warning in hook_png(..., cmd = "pngquant", post_process = function(x) { :
  cannot find pngquant; please install and put it in PATH

Quitting from non-parametric-rcpp.Rmd:197-206 [unnamed-chunk-7]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<error/rlang_error>
Error in `[.data.table`:
! attempt access index 1/1 in VECTOR_ELT
---
Backtrace:
    ▆
 1. ├─global clock(kernelDensity(X, xout = xg, bw = b))
 2. └─smoothemplik::kernelDensity(X, xout = xg, bw = b)
 3.   └─smoothemplik::prepareKernel(...)
 4.     └─smoothemplik:::.deduplicate(xy)
 5.       ├─x[, `:=`(`(id)` = .GRP, `(count)` = .N), by = names(x)]
 6.       └─data.table:::`[.data.table`(...)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Error: processing vignette 'non-parametric-rcpp.Rmd' failed with diagnostics:
attempt access index 1/1 in VECTOR_ELT
--- failed re-building 'non-parametric-rcpp.Rmd'

SUMMARY: processing the following files failed:
  'choice-of-SEL-weights.Rmd' 'non-parametric-rcpp.Rmd'

Error: Vignette re-building failed.
Execution halted