Error(s) in re-building vignettes:
  ...
--- re-building ‘tramnet.Rnw’ using knitr
Loading required package: tram
Loading required package: mlt
Loading required package: basefun
Loading required package: variables
Loading required package: CVXR

Attaching package: 'CVXR'

The following object is masked from 'package:stats':

    power

Loading required package: mlrMBO
Loading required package: mlr
Loading required package: ParamHelpers
Warning message: 'mlr' is in 'maintenance-only' mode since July
2019. Future development will only happen in 'mlr3'
(<https://mlr3.mlr-org.com>). Due to the focus on 'mlr3' there
might be uncaught bugs meanwhile in {mlr} - please consider
switching.
Loading required package: smoof
Loading required package: checkmate
Loading required package: survival
Welcome to penalized. For extended examples, see vignette("penalized").
Loading required package: Matrix
Loaded glmnet 4.1-3

Attaching package: 'coin'

The following object is masked from 'package:CVXR':

    size

The following object is masked from 'package:variables':

    support


warning: solve(): system is singular (rcond: 1.91008e-17); attempting approx solution

warning: solve(): system is singular; attempting approx solution

warning: solve(): system is singular (rcond: 1.92453e-17); attempting approx solution

warning: solve(): system is singular; attempting approx solution

warning: solve(): system is singular (rcond: 1.92453e-17); attempting approx solution

warning: solve(): system is singular; attempting approx solution

warning: solve(): system is singular (rcond: 1.92453e-17); attempting approx solution
Error: processing vignette ‘tramnet.Rnw’ failed with diagnostics:
Running ‘texi2dvi’ on ‘tramnet.tex’ failed.
LaTeX errors:
! Missing $ inserted.
<inserted text> 
                $
l.772 x <- model.matrix(~ 0 + x, ...)x_
                                       scaled <- scale(x)mt <- tramnet(model...
! Emergency stop.
<inserted text> 
                $
l.772 x <- model.matrix(~ 0 + x, ...)x_
                                       scaled <- scale(x)mt <- tramnet(model...
!  ==> Fatal error occurred, no output PDF file produced!
--- failed re-building ‘tramnet.Rnw’

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

Error: Vignette re-building failed.
Execution halted