Error(s) in re-building vignettes:
  ...
--- re-building ‘data-beta.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.

Attaching package: 'matlib'

The following object is masked from 'package:rgl':

    GramSchmidt

Loading required namespace: rmarkdown
PhantomJS not found. You can install it with webshot::install_phantomjs(). If it is installed, please make sure the phantomjs executable can be found via the PATH variable.
Warning in normalizePath(f2) :
  path[1]="webshot3af25d45fb9.png": No such file or directory
Warning in file(con, "rb") :
  cannot open file 'webshot3af25d45fb9.png': No such file or directory
Quitting from lines 162-183 (data-beta.Rmd) 
Error: processing vignette 'data-beta.Rmd' failed with diagnostics:
cannot open the connection
--- failed re-building ‘data-beta.Rmd’

--- re-building ‘det-ex1.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.
--- finished re-building ‘det-ex1.Rmd’

--- re-building ‘det-ex2.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.
--- finished re-building ‘det-ex2.Rmd’

--- re-building ‘eigen-ex1.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.
--- finished re-building ‘eigen-ex1.Rmd’

--- re-building ‘eigen-ex2.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.
--- finished re-building ‘eigen-ex2.Rmd’

--- re-building ‘ginv.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.
--- finished re-building ‘ginv.Rmd’

--- re-building ‘gramreg.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.
--- finished re-building ‘gramreg.Rmd’

--- re-building ‘inv-ex1.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.
--- finished re-building ‘inv-ex1.Rmd’

--- re-building ‘inv-ex2.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.
--- finished re-building ‘inv-ex2.Rmd’

--- re-building ‘linear-equations.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.

Attaching package: 'matlib'

The following object is masked from 'package:rgl':

    GramSchmidt

Loading required namespace: rmarkdown
PhantomJS not found. You can install it with webshot::install_phantomjs(). If it is installed, please make sure the phantomjs executable can be found via the PATH variable.
Warning in normalizePath(f2) :
  path[1]="webshot158e1b5230da.png": No such file or directory
Warning in file(con, "rb") :
  cannot open file 'webshot158e1b5230da.png': No such file or directory
Quitting from lines 173-174 (linear-equations.Rmd) 
Error: processing vignette 'linear-equations.Rmd' failed with diagnostics:
cannot open the connection
--- 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