Error(s) in re-building vignettes:
--- re-building 'blocksrecs.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
--- finished re-building 'blocksrecs.Rmd'

--- re-building 'cdata.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
--- finished re-building 'cdata.Rmd'

--- re-building 'control_table_keys.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
--- finished re-building 'control_table_keys.Rmd'

--- re-building 'design.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
--- finished re-building 'design.Rmd'

--- re-building 'exercises.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
--- finished re-building 'exercises.Rmd'

--- re-building 'general_transform.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
--- finished re-building 'general_transform.Rmd'

--- re-building 'operators.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
Quitting from lines 141-151 (operators.Rmd) 
Error: processing vignette 'operators.Rmd' failed with diagnostics:
object 'd_td' not found
--- failed re-building 'operators.Rmd'

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

Error: Vignette re-building failed.
Execution halted