Error(s) in re-building vignettes:
  ...
--- re-building ‘article.Rnw’ using knitr
Loading required package: ggplot2
Loading required package: plotrix
Loading required package: survival
Warning: The following aesthetics were dropped during statistical
transformation: weight
ℹ This can happen when ggplot fails to infer the correct grouping
  structure in the data.
ℹ Did you forget to specify a `group` aesthetic or to convert a
  numerical variable into a factor?
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning: The following aesthetics were dropped during statistical
transformation: weight
ℹ This can happen when ggplot fails to infer the correct grouping
  structure in the data.
ℹ Did you forget to specify a `group` aesthetic or to convert a
  numerical variable into a factor?
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning in rq.fit.br(wx, wy, tau = tau, ...) :
  Solution may be nonunique
Warning: The following aesthetics were dropped during statistical
transformation: weight
ℹ This can happen when ggplot fails to infer the correct grouping
  structure in the data.
ℹ Did you forget to specify a `group` aesthetic or to convert a
  numerical variable into a factor?
Error: processing vignette ‘article.Rnw’ failed with diagnostics:
Running ‘texi2dvi’ on ‘article.tex’ failed.
LaTeX errors:
! LaTeX Error: Unicode character ℹ (U+2139)
               not set up for use with LaTeX.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
! Emergency stop.
 ...                                              
                                                  
l.1084 ...plot fails to infer the correct grouping
                                                  
!  ==> Fatal error occurred, no output PDF file produced!
--- failed re-building ‘article.Rnw’

--- re-building ‘comparison-example.Rnw’ using knitr
--- finished re-building ‘comparison-example.Rnw’

--- re-building ‘desirability-example.Rnw’ using knitr
--- finished re-building ‘desirability-example.Rnw’

--- re-building ‘randomizeR-refCard.Rnw’ using knitr
--- finished re-building ‘randomizeR-refCard.Rnw’

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

Error: Vignette re-building failed.
Execution halted