Error(s) in re-building vignettes:
duplicated vignette title:
  'Introduction to SIBER'

--- re-building 'Centroid-Vectors.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
--- finished re-building 'Centroid-Vectors.Rmd'

--- re-building 'Customising-Plots-Manually.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
--- finished re-building 'Customising-Plots-Manually.Rmd'

--- re-building 'Ellipse-Overlap.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
--- finished re-building 'Ellipse-Overlap.Rmd'

--- re-building 'Introduction-to-SIBER.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
--- finished re-building 'Introduction-to-SIBER.Rmd'

--- re-building 'Points-Inside-Outside-Ellipse.Rmd' using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available, because the rmarkdown package is not installed. Please install it.
Quitting from lines 22-33 (Points-Inside-Outside-Ellipse.Rmd) 
Error: processing vignette 'Points-Inside-Outside-Ellipse.Rmd' failed with diagnostics:
could not find function "generateSiberGroup"
--- failed re-building 'Points-Inside-Outside-Ellipse.Rmd'

SUMMARY: processing the following file failed:
  'Points-Inside-Outside-Ellipse.Rmd'

Error: Vignette re-building failed.
Error: Duplicate vignette titles.
  Ensure that the %\VignetteIndexEntry lines in the vignette sources
  correspond to the vignette titles.
Execution halted