The downloaded source packages are in
‘C:\Users\Shambhu Paudel\AppData\Local\Temp\RtmpkzEBQu\downloaded_packages’
Warning message:
In install.packages(“rstan”, type = “source”) :
installation of package ‘rstan’ had non-zero exit status
The quotation marks are causing the flag to be parsed incorrectly, and you’re forcing the use of the 64-bit compiler (mingw_64) for both 32-bit and 64-bit contexts.
Try removing that line entirely, so your Makevars.win file should just be:
The downloaded source packages are in
‘C:\Users\Shambhu Paudel\AppData\Local\Temp\RtmpkzEBQu\downloaded_packages’
Warning message:
In install.packages(“rstan”, type = “source”) :
installation of package ‘rstan’ had non-zero exit status