Error(s) in re-building vignettes:
--- re-building ‘v1_simple_normal.Rmd’ using rmarkdown
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
--- finished re-building ‘v1_simple_normal.Rmd’

--- re-building ‘v2_advanced_normal.Rmd’ using rmarkdown
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
--- finished re-building ‘v2_advanced_normal.Rmd’

--- re-building ‘v3_expert_normal.Rmd’ using rmarkdown
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  zero-length arrow is of indeterminate angle and so skipped
--- finished re-building ‘v3_expert_normal.Rmd’

--- re-building ‘v4_simple_non_normal.Rmd’ using rmarkdown
File figure/barplot-1.png not found in resource path
Error: processing vignette 'v4_simple_non_normal.Rmd' failed with diagnostics:
pandoc document conversion failed with error 99
--- failed re-building ‘v4_simple_non_normal.Rmd’

--- re-building ‘v5_advanced_non_normal.Rmd’ using rmarkdown
File figure/barplot-1.png not found in resource path
Error: processing vignette 'v5_advanced_non_normal.Rmd' failed with diagnostics:
pandoc document conversion failed with error 99
--- failed re-building ‘v5_advanced_non_normal.Rmd’

--- re-building ‘v6_expert_non_normal.Rmd’ using rmarkdown
File figure/barplot-1.png not found in resource path
Error: processing vignette 'v6_expert_non_normal.Rmd' failed with diagnostics:
pandoc document conversion failed with error 99
--- failed re-building ‘v6_expert_non_normal.Rmd’

SUMMARY: processing the following files failed:
  ‘v4_simple_non_normal.Rmd’ ‘v5_advanced_non_normal.Rmd’
  ‘v6_expert_non_normal.Rmd’

Error: Vignette re-building failed.
Execution halted