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Get or set the file path to the CmdStan installation

Source: R/path.R
set_cmdstan_path.Rd

Use the set_cmdstan_path() function to tell CmdStanR where the CmdStan installation is located. Once the path has been set, cmdstan_path() will return the full path to the CmdStan installation and cmdstan_version() will return the CmdStan version number. See Details for how to avoid manually setting the path in each R session.

Usage

set_cmdstan_path(path = NULL)

cmdstan_path()

cmdstan_version(error_on_NA = TRUE)

Arguments

path

(string) The full file path to the CmdStan installation. If NULL (the default) then the path is set using the "CMDSTAN" environment variable when available, otherwise the default path used by install_cmdstan() if it exists.

error_on_NA

(logical) Should an error be thrown if CmdStan is not found. The default is TRUE. If FALSE, cmdstan_version() returns NULL.

Value

set_cmdstan_path() invisibly returns the supplied or automatically resolved path. If path = NULL and no installation is found, it invisibly returns NULL.

cmdstan_path() returns the current CmdStan path as a string or it errors if no path has been set.

cmdstan_version() returns the CmdStan version as a string. If CmdStan is not found, it errors when error_on_NA = TRUE and returns NULL when error_on_NA = FALSE.

Details

Before the package can be used it needs to know where the CmdStan installation is located. When the package is loaded it tries to help automate this to avoid having to manually set the path every session:

  • If the environment variable "CMDSTAN" points directly to a valid CmdStan installation at load time, that path is used for the R session. If it instead points to an existing parent directory containing versioned CmdStan installations, the installation with the largest version number is used.

  • If no environment variable is found when loaded but any directory in the form ".cmdstan/cmdstan-[version]" (e.g., ".cmdstan/cmdstan-2.37.0"), exists in the user's home directory (not the current working directory), then the path to the CmdStan installation with the largest version number is used for the R session. On Windows the home directory is determined from USERPROFILE, falling back to HOMEDRIVE and HOMEPATH. On other platforms it is determined from HOME. This is the same default directory that install_cmdstan() uses.

It is always possible to change the path after loading the package using set_cmdstan_path(path).

See also

install_cmdstan(), cmdstan_default_install_path(), and cmdstan_default_path()