Error(s) in re-building vignettes:
  ...
--- re-building ‘model.Rmd’ using rmarkdown
--- finished re-building ‘model.Rmd’

--- re-building ‘performance.Rmd’ using rmarkdown
** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/melt.Rcheck/vign_test/melt/vignettes/performance_files/figure-html/unnamed-chunk-4-1.png
2100x1500 pixels, 8 bits/pixel, 255 colors in palette
Reducing image to 8 bits/pixel, grayscale
Input IDAT size = 51205 bytes
Input file size = 52132 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 38401
  zc = 9  zm = 8  zs = 1  f = 0
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5		IDAT size = 32574
  zc = 9  zm = 8  zs = 1  f = 5		IDAT size = 31889
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 1  f = 5		IDAT size = 31889

Output IDAT size = 31889 bytes (19316 bytes decrease)
Output file size = 31967 bytes (20165 bytes = 38.68% decrease)

** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/melt.Rcheck/vign_test/melt/vignettes/performance_files/figure-html/unnamed-chunk-6-1.png
2100x1500 pixels, 8 bits/pixel, 255 colors in palette
Reducing image to 8 bits/pixel, grayscale
Input IDAT size = 50013 bytes
Input file size = 50940 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 38531
  zc = 9  zm = 8  zs = 1  f = 0
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5		IDAT size = 32337
  zc = 9  zm = 8  zs = 1  f = 5		IDAT size = 31795
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 1  f = 5		IDAT size = 31795

Output IDAT size = 31795 bytes (18218 bytes decrease)
Output file size = 31873 bytes (19067 bytes = 37.43% decrease)

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

--- re-building ‘article.Rnw’ using knitr
Error: processing vignette 'article.Rnw' failed with diagnostics:
Running 'texi2dvi' on 'article.tex' failed.
LaTeX errors:
! Undefined control sequence.
l.914 \hlkwd{library}\hldef
                           {(}\hlsng{"melt"}\hldef{)}
? 
! Emergency stop.
! Emergency stop.
l.914 
      
End of file on the terminal!

!  ==> Fatal error occurred, no output PDF file produced!
--- failed re-building ‘article.Rnw’

SUMMARY: processing the following file failed:
  ‘article.Rnw’

Error: Vignette re-building failed.
Execution halted