Error(s) in re-building vignettes:
  ...
--- re-building ‘chebpol.Rnw’ using knitr
Error: processing vignette ‘chebpol.Rnw’ failed with diagnostics:
Running ‘texi2dvi’ on ‘chebpol.tex’ failed.
LaTeX errors:
! Missing $ inserted.
<inserted text> 
                $
l.134 f <- function(x) cos(3*pi*x)/(1+25*(x-0.25)^
                                                  2)ch <- ipol(f,dims=15,met...
! Emergency stop.
<inserted text> 
                $
l.134 f <- function(x) cos(3*pi*x)/(1+25*(x-0.25)^
                                                  2)ch <- ipol(f,dims=15,met...
!  ==> Fatal error occurred, no output PDF file produced!
--- failed re-building ‘chebpol.Rnw’

--- re-building ‘chebusage.Rnw’ using knitr
Error: processing vignette ‘chebusage.Rnw’ failed with diagnostics:
Running ‘texi2dvi’ on ‘chebusage.tex’ failed.
LaTeX errors:
! Missing $ inserted.
<inserted text> 
                $
l.124 ...')grid <- list(x=seq(-1,1,length.out=12)^
                                                  3L, y=sort(c(0,runif(10,-1...
! Emergency stop.
<inserted text> 
                $
l.124 ...')grid <- list(x=seq(-1,1,length.out=12)^
                                                  3L, y=sort(c(0,runif(10,-1...
!  ==> Fatal error occurred, no output PDF file produced!
--- failed re-building ‘chebusage.Rnw’

--- re-building ‘stalker.Rnw’ using knitr
Error: processing vignette ‘stalker.Rnw’ failed with diagnostics:
Running ‘texi2dvi’ on ‘stalker.tex’ failed.
LaTeX errors:
! Missing $ inserted.
<inserted text> 
                $
l.368 ...- function(t) tcubic <- function(t) -2*t^
                                                  3 + 3*t^2sigmoid <- functi...
! Emergency stop.
<inserted text> 
                $
l.368 ...- function(t) tcubic <- function(t) -2*t^
                                                  3 + 3*t^2sigmoid <- functi...
!  ==> Fatal error occurred, no output PDF file produced!
--- failed re-building ‘stalker.Rnw’

SUMMARY: processing the following files failed:
  ‘chebpol.Rnw’ ‘chebusage.Rnw’ ‘stalker.Rnw’

Error: Vignette re-building failed.
Execution halted