Error(s) in re-building vignettes:
--- re-building ‘data-beta.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
Quitting from lines 162-183 (data-beta.Rmd) 
Error: processing vignette 'data-beta.Rmd' failed with diagnostics:
Saving a widget with selfcontained = TRUE requires pandoc. See here to learn more https://bookdown.org/yihui/rmarkdown-cookbook/install-pandoc.html
--- failed re-building ‘data-beta.Rmd’

--- re-building ‘det-ex1.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘det-ex1.Rmd’

--- re-building ‘det-ex2.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘det-ex2.Rmd’

--- re-building ‘eigen-ex1.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘eigen-ex1.Rmd’

--- re-building ‘eigen-ex2.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘eigen-ex2.Rmd’

--- re-building ‘ginv.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘ginv.Rmd’

--- re-building ‘gramreg.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘gramreg.Rmd’

--- re-building ‘inv-ex1.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘inv-ex1.Rmd’

--- re-building ‘inv-ex2.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘inv-ex2.Rmd’

--- re-building ‘linear-equations.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
Quitting from lines 173-174 (linear-equations.Rmd) 
Error: processing vignette 'linear-equations.Rmd' failed with diagnostics:
Saving a widget with selfcontained = TRUE requires pandoc. See here to learn more https://bookdown.org/yihui/rmarkdown-cookbook/install-pandoc.html
--- failed re-building ‘linear-equations.Rmd’

SUMMARY: processing the following files failed:
  ‘data-beta.Rmd’ ‘linear-equations.Rmd’

Error: Vignette re-building failed.
Execution halted