Error(s) in re-building vignettes:
  ...
--- re-building ‘UAHDataScienceUC.Rmd’ using rmarkdown
** Processing: /home/hornik/tmp/R.check/r-release-gcc/Work/PKGS/UAHDataScienceUC.Rcheck/vign_test/UAHDataScienceUC/vignettes/UAHDataScienceUC_files/figure-html/unnamed-chunk-3-1.png
288x288 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 6908 bytes
Input file size = 6986 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 5147
  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 = 5147

Output IDAT size = 5147 bytes (1761 bytes decrease)
Output file size = 5225 bytes (1761 bytes = 25.21% decrease)

** Processing: /home/hornik/tmp/R.check/r-release-gcc/Work/PKGS/UAHDataScienceUC.Rcheck/vign_test/UAHDataScienceUC/vignettes/UAHDataScienceUC_files/figure-html/unnamed-chunk-4-1.png
288x288 pixels, 8 bits/pixel, 256 colors in palette
Reducing image to 8 bits/pixel, grayscale
Input IDAT size = 4099 bytes
Input file size = 4957 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 3666
  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 = 3666

Output IDAT size = 3666 bytes (433 bytes decrease)
Output file size = 3744 bytes (1213 bytes = 24.47% decrease)

** Processing: /home/hornik/tmp/R.check/r-release-gcc/Work/PKGS/UAHDataScienceUC.Rcheck/vign_test/UAHDataScienceUC/vignettes/UAHDataScienceUC_files/figure-html/unnamed-chunk-5-1.png
288x288 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 5353 bytes
Input file size = 5431 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 3970
  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 = 3970

Output IDAT size = 3970 bytes (1383 bytes decrease)
Output file size = 4048 bytes (1383 bytes = 25.46% decrease)


Quitting from lines 84-93 [unnamed-chunk-6] (UAHDataScienceUC.Rmd)
Error: processing vignette 'UAHDataScienceUC.Rmd' failed with diagnostics:
Lapack routine dgesv: system is exactly singular: U[2,2] = 0
--- failed re-building ‘UAHDataScienceUC.Rmd’

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

Error: Vignette re-building failed.
Execution halted