January 17, 2022
Memory requirements for Mplus (both RAM and virtual memory) depend on the type of analysis and the amount of data. For example, analyses using numerical integration with large samples can be computationally heavy and may require a large amount of memory.
Mplus 32-bit on 32-bit Windows: The Windows 32-bit operating system limits all applications to a maximum of 2GB of total memory (RAM and virtual memory).
Mplus is capable of using an additional 1 GB of total memory, for a maximum of 3 GB, on some Windows 32-bit operating systems. For Mplus to use the additional memory, the /3GB switch must be specified in Boot.ini. This switch allows applications like Mplus, that are "large address aware", to use 1 GB of additional total memory above 2 GB.
Note that changes to the Boot.ini may have undesirable effects. Caution should be taken when making any changes. Muthen & Muthen is not responsible for any problems that may arise if such changes are attempted and does not provide support for any problems related to these changes.
Mplus 32-bit on 64-bit Windows: The Windows 64-bit operating system limits all 32-bit applications to a maximum of 2GB (or 4GB for applications like Mplus that are "large address aware") of total memory (RAM and virtual memory). Note that the /3GB switch is not applicable to Windows 64-bit operating systems.
Mplus on 64-bit Windows: The Windows 64-bit operating system limits all 64-bit applications to a maximum of 8 terabytes (8000GB) of total memory (RAM and virtual memory).
Mplus on Mac OS X:Mplus does not run natively on Apple’s new Macs with the M1 chip. Mplus does run on M1 Macs using Rosetta, a translation layer, that allows Intel-based software to run on the M1 chip. More information about this can be found on Apple’s website at https://developer.apple.com/documentation/apple-silicon/about-the-rosetta-translation-environment
Note that it has been reported that the performance of Mplus does diminish on M1 Macs under the Rosetta translation. There are currently no plans to make Mplus run natively on the M1 Macs. This decision is based on the availability of the current compiler used by Mplus. Future availability of Mplus on the M1 Macs may be impacted as a result.
Mplus on Linux: Mplus is available on the Linux 64-bit operating systems from the command line. The Linux distributions that have been tested are Ubuntu, RedHat, Fedora, Debian, and Gentoo. Mplus for Linux does not run on the Sun Solaris operating system. The multiprocessing feature in Mplus for Linux is the standard multiprocessing feature available in Mplus for Windows. The Linux version does not currently have special cluster computing capabilities.
The PATH Environment Variable
The Run Mplus option in the Mplus Editor requires that the Mplus installation directory be listed in the PATH environment variable. The PATH environment variable must also be set at the system level for Mplus to work properly in a multiple user environment. The Mplus installation process will try to set the PATH environment variable at the system level.
If this attempt fails, problems may arise when using the Run Mplus option in the Mplus Editor or when trying to update Mplus. Users will be alerted that Mplus is unable to start when running Mplus or Mplus is not found when updating Mplus.
To fix this problem, the PATH environment variable can be set manually.
Instructions for Windows 7:
Mplus Temporary Files
Mplus uses intermediate files for controlling outputs. These files are created in the working directory. The working directory is usually the directory with the input file. There is one instance when it is not and that is when Mplus is first opened and the recent file list is used to open a previous input file. To ensure that the working directory is always the directory with the input file, always use the File -> Open/Save options for opening/saving an input file.
There is one other temporary file that is created by Mplus but not stored in the working directory. This file does not contain any specific results from the current run. The only information written to the file is the name of the output file. Mplus stores this file in the directory specified by the TEMP environment variable -- a setting on most computers with the Windows operating system. There is no specific setting in Mplus to change the location of this directory. To change the location where Mplus stores this file, the TEMP environment variable must be changed. This will affect other programs that use the TEMP environment variable.
Instructions for Mplus Silent Installation for Windows
In order to perform a silent installation, the installer must be run once to get the response file used. The installer file must be started via the command line using the following instructions.