You will need to set three environment variables so that the JGR launcher knows where R is.
Deducer: A GUI for RR_HOME to the location of the R installation.
R_LIBS to the location of your package library directory.
DYLD_LIBRARY_PATH to the directory containing your R dynamic library (i.e. on the mac, the folder containing libR.dylib)
For example I installed R-2.10.1 to my user folder running mac os x. I use the following script (named startJGR and put in the same folder as JGR.app) to start up JGR.
setenv R_LIBS $HOME"/R-2.10.1/library" setenv R_HOME $HOME"/R-2.10.1" setenv DYLD_LIBRARY_PATH $HOME"/R-2.10.1/lib" setenv NOAWT 1 ./JGR.app/Contents/MacOS/JGR
to run this script, at the terminal (while in the same directory) I run:
csh ./startJGR
if you get a permission error, run chmod 755 startJGR
in windows, the launcher jgr.exe also accepts some parameters to specify R's location. for example if I have a custom library location in my documents directory, I can create a file names launchJGR.bat, located in the same folder as jgr.exe containing the text:
set R_LIBS=%USERPROFILE%\Documents\R\win-library\2.11 jgr.exe --libpath=%USERPROFILE%\Documents\R\win-library\2.11