Error(s) in re-building vignettes:
  ...
--- re-building 'DriveML.Rmd' using rmarkdown
Quitting from lines 169-171 (DriveML.Rmd) 
Error: processing vignette 'DriveML.Rmd' failed with diagnostics:
data length differs from size of matrix: [8 != 2 x 2]
--- failed re-building 'DriveML.Rmd'

SUMMARY: processing the following file failed:
  'DriveML.Rmd'

Error: Vignette re-building failed.
Execution halted
Error(s) in re-building vignettes:
  ...
--- re-building ‘DriveML.Rmd’ using rmarkdown
Quitting from lines 169-171 (DriveML.Rmd) 
Error: processing vignette 'DriveML.Rmd' failed with diagnostics:
data length differs from size of matrix: [8 != 2 x 2]
--- failed re-building ‘DriveML.Rmd’

SUMMARY: processing the following file failed:
  ‘DriveML.Rmd’

Error: Vignette re-building failed.
Execution halted
Undeclared packages ‘caret’, ‘pdp’ in Rd xrefs
Error(s) in re-building vignettes:
  ...
--- re-building ‘DriveML.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
Quitting from lines 281-283 (DriveML.Rmd) 
Error: processing vignette 'DriveML.Rmd' failed with diagnostics:
Invalid unit
--- failed re-building ‘DriveML.Rmd’

SUMMARY: processing the following file failed:
  ‘DriveML.Rmd’

Error: Vignette re-building failed.
Execution halted