Windows

In Windows, if you use the current (2025-03-09) version of the installer the program will be, most likely, in:

C:\Program Files\APSIM2024.2.7382.0\bin\Models.exe

Notice that for each new build of APSIM-X the path will change. After ‘APSIM’ is the year and month, and version separated by a period. In this case ‘2021.08.12.6707’. In the folder ‘bin’ (for ‘binary’) there are many libraries (‘.dll files’) and some executables. The ‘Models.exe’ is the one that can run .apsimx files.

When trying to invoke that line at the command line, the space after ‘Program’ is a problem. There are some possible solutions. One is to add quotations (for example see ‘shQuote’ function in R). Another option is to use Windows short name paths, which in this case, for ‘Program Files’ is ‘PROGRA~1’ (but this can change). If running the program from R, for example, the separator needs to be either a double backslash ‘\\’ or a forward slash ‘/’. So one example would be:

C:/PROGRA~1/APSIM2024.2.7382.0/bin/Models.exe or

C:\\PROGRA~1\\APSIM2024.2.7382.0\\bin\\Models.exe

The backslash (“\”) is an escape character in R, so you can’t use it within strings.

After this, the name of the file that you want to run needs to be included. For example,

C:/PROGRA~1/APSIM2024.2.7382.0/bin/Models.exe ./Wheat.apsimx.

Notice the “./”, without this, it will likely not work under Windows. (update: this issue has been addressed in current version of APSIM Next Gen). However, the previous string cannot be passed directly to a Windows shell. It needs to be translated with the forward slashes (“/”) converted to backslashes (“\”).

So to run the previous command in Windows from within R this is one way:

run.strng <- "C:/PROGRA~1/APSIM2024.2.7382.0/bin/Models.exe ./Wheat.apsimx"
shell(cmd = run.strng, translate = TRUE, intern = TRUE)

Unix (Mac) or Linux (Debian)

For current versions of APSIM Next Gen, this command should be able to run from the command line:

/Applications/APSIM2024.2.7382.0.app/Contents/Resources/bin/Models ./Wheat.apsimx

Mono is not required.

## Mac
run.string.mac <- "mono /Applications/APSIM2021.01.14.6010.app/Contents/Resources/Bin/Models.exe ./Wheat.apsimx"
system(command = run.string.mac, intern = TRUE)
## Debian
run.string.debian <- "mono /usr/local/lib/apsim/2019.10.04.4236/Bin/Models.exe ./Wheat.apsimx"
system(command = run.string.debian, intern = TRUE)

Functions in the apsimx package

Having to change scripts every time you install a new version of APSIM-X or when you change operating system is certainly problematic and for this reason apsimx tries to ‘guess’ where APSIM-X is installed and where the ‘Examples’ are located. The functions to do this are:

Executable: auto_detect_apsimx()

Examples: auto_detect_apsimx_examples()

Which will return the path to the executable and the directory where the examples are located. These functions are supposed to work whether you are using Windows, Mac or Linux. The function ‘auto_detect_apsimx’ is not exported, so in order to expose it, you need ‘apsimx:::auto_detect_apsimx()’. This function is meant to work with the current binary distributions (as opposed to source code). (I’m guessing that if you are building APSIM-X from source code, you do not need this information.)

If multiple versions of APSIM-X are installed, apsimx will choose the newest one, but it will issue a warning. If you want to supress this warning change this setting using the ‘apsimx_options’. If APSIM-X is installed in an alternative location which make the above functions fail it is possible to set these paths manually using the ‘apsimx_options’ function. This information applies to APSIM ‘Classic’ (use apsim_options instead).

In addition, when loaded, the apsimx package will try to detect the presence of APSIM-X and, if not found, it will issue a warning with instructions to set the path manually using ‘apsimx_options’. If you have a previous version of APSIM installed (7.x) or multiple versions of both the ‘old’ and ‘new’ this might be potentially problematic, but it is hard for me now to consider these endless possibilities.

sessionInfo()
Sys.info()[["sysname"]]
Sys.info()[["release"]]
Sys.info()[["version"]]
if(.Platform$OS.type == "unix") system(command = "mono --version", intern = TRUE)
R.version