Error(s) in re-building vignettes:
  ...
--- re-building ‘scholar.Rmd’ using rmarkdown
** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/scholar.Rcheck/vign_test/scholar/vignettes/scholar_files/figure-html/unnamed-chunk-4-1.png
672x480 pixels, 8 bits/pixel, 256 colors in palette
Reducing image to 8 bits/pixel, grayscale
Input IDAT size = 11052 bytes
Input file size = 11922 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 9163
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 9116
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  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 = 0		IDAT size = 9116

Output IDAT size = 9116 bytes (1936 bytes decrease)
Output file size = 9194 bytes (2728 bytes = 22.88% decrease)

** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/scholar.Rcheck/vign_test/scholar/vignettes/scholar_files/figure-html/unnamed-chunk-5-1.png
672x480 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 18439 bytes
Input file size = 18541 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 16985
  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
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 16985

Output IDAT size = 16985 bytes (1454 bytes decrease)
Output file size = 17063 bytes (1478 bytes = 7.97% decrease)

** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/scholar.Rcheck/vign_test/scholar/vignettes/scholar_files/figure-html/unnamed-chunk-6-1.png
672x480 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 33816 bytes
Input file size = 33942 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 32469
  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 = 31721
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 5		IDAT size = 31721

Output IDAT size = 31721 bytes (2095 bytes decrease)
Output file size = 31799 bytes (2143 bytes = 6.31% decrease)

** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/scholar.Rcheck/vign_test/scholar/vignettes/scholar_files/figure-html/unnamed-chunk-6-2.png
672x480 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 34064 bytes
Input file size = 34190 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 29498
  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
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 29498

Output IDAT size = 29498 bytes (4566 bytes decrease)
Output file size = 29576 bytes (4614 bytes = 13.50% decrease)


Quitting from lines 120-125 [unnamed-chunk-7] (scholar.Rmd)
Error: processing vignette 'scholar.Rmd' failed with diagnostics:
is.response(x) is not TRUE
--- failed re-building ‘scholar.Rmd’

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

Error: Vignette re-building failed.
Execution halted