Stata 15 help for flavors

Title

[U] 5 Flavors of Stata

Contents

5.1 Platforms

5.2 Stata/MP, Stata/SE, and Stata/IC 5.2.1 Determining which version you own 5.2.2 Determining which version is installed

5.3 Size limits of Stata/MP, SE, and IC

5.4 Speed comparison of Stata/MP, SE, and IC

5.5 Feature comparison of Stata/MP, SE, and IC

5.1 Platforms

Stata is available for a variety of systems, including

Stata for Windows, 64-bit x86-64 Stata for Windows, 32-bit x86

Stata for Mac, 64-bit x86-64

Stata for Linux, 64-bit x86-64 Stata for Linux, 32-bit x86

Which version of Stata you run does not matter -- Stata is Stata. You instruct Stata in the same way and Stata produces the same results, right down to the random-number generator. Even files can be shared. A dataset created on one computer can be used on any other computer, and the same goes for graphs, programs, or any file Stata uses or produces. Moving files across platforms is simply a matter of copying them; no translation is required.

Some computers, however, are faster than others. Some computers have more memory than others. Computers with more memory, and faster computers, are better.

The list above includes both 64- and 32-bit computers. 64-bit Stata runs faster than 32-bit Stata and 64-bit Stata will allow processing data in excess of 2 gigabytes, assuming you have enough memory. 32-bit Stata will run on 64-bit hardware.

When you purchase Stata, you may install it on any of the above platforms. Stata licenses are not locked to a single operating system.

5.2 Stata/MP, Stata/SE, and Stata/IC

Stata is available in three flavors, although perhaps sizes would be a better word. The flavors are, from largest to smallest, Stata/MP, Stata/SE, and Stata/IC.

Stata/MP is the multiprocessor version of Stata. It runs on multiple CPUs or on multiple cores, from 2 to 64. Stata/MP uses however many cores you tell it to use (even one), up to the number of cores for which you are licensed. Stata/MP is the fastest version of Stata. Even so, all the details of parallelization are handled internally and you use Stata/MP just like you use any other flavor of Stata. You can read about how Stata/MP works and see how its speed increases with more cores in the Stata/MP performance report at http://www.stata.com/statamp/report.pdf.

Stata/SE is like Stata/MP, but for single CPUs. Stata/SE will run on multiple CPUs or multiple core computers, but it will use only one of the CPUs or cores. SE stands for special edition.

In addition to being the fastest version of Stata, Stata/MP is also the largest. Stata/MP allows up to 1,099,511,627,775 observations in theory, but you can undoubtedly run out of memory first. You may have up to 120,000 variables with Stata/MP. Statistical models may have up to 11,000 variables.

Stata/SE allow up to 2,147,583,647 observations, assuming you have enough memory. You may have up to 32,767 variables, and, like Stata/MP, statistical models may have up to 11,000 variables.

Stata/IC is standard Stata. Up to 2,147,583,647 observations and 2,048 variables are allowed, depending on memory. Statistical models may have up to 800 variables.

5.2.1 Determining which version you own

Check your License and Activation Key. Included with every copy of Stata is a License and Activation Key that contains codes that you will input during installation. This determines which flavor of Stata you have and for which platform.

Contact us or your distributor if you want to upgrade from one flavor to another. Usually, all you need is an upgraded License and Activation Key with the appropriate codes. All flavors of Stata are on the same DVD.

If you purchased one flavor of Stata and want to use a lessor version, you may. You might want to do this if you had a large computer at work and a smaller one at home. Please remember, however, that you have only one license (or however many licenses you purchased). You may, both legally and ethically, install Stata on both computers and then use one or the other, but you should not use them both simultaneously.

5.2.2 Determining which version is installed

If Stata is already installed, you can find out which Stata you are using by entering Stata as you normally do and typing about:

. about

Stata/IC 15.1 for Windows (64-bit x86-64) Born date Copyright (C) 1985-2017 StataCorp LLC

Total physical memory: 8388608 KB Available physical memory: 937932 KB

10-user 32-core Stata network perpetual license: Serial number: 5015041234 Licensed to: Alan R. Riley StataCorp

5.3 Size limits of Stata/MP, SE, and IC

Here are some of the different size limits for Stata/MP, Stata/SE, and Stata/IC. See limits for a longer list.

Maximum size limits for Stata/MP, Stata/SE, and Stata/IC

Stata/MP Stata/SE Stata/IC --------------------------------------------------------------------------- # observations 1,099,511,627,775 2,147,483,647 2,147,483,647 # variables 120,000 32,767 2,048 Maximum matrix size (matsize) 10,998 10,998 798 # bytes in a macro 15,480,200 4,227,143 264,392 # bytes in a command 15,480,216 4,227,159 264,408 ---------------------------------------------------------------------------

Stata/MP allows more variables and observations, longer macros, and a longer command line than Stata/SE. Stata/SE allows more variables, larger models, longer macros, and a longer command line than Stata/IC. The longer command line and macro length are required because of the greater number of variables allowed. The larger model means that Stata/MP and Stata/SE can fit statistical models with more independent variables.

5.4 Speed comparison of Stata/MP, SE, and IC

We have written a white paper comparing the performance of Stata/MP with Stata/SE; see http://www.stata.com/statamp/report.pdf. The white paper includes command-by-command performance measurements.

In summary, on a dual-core computer, Stata/MP will run commands in 71% of the time required by Stata/SE. There is variation; some commands run in half the time and others are not sped up at all. Statistical estimation commands run in 59% of the time. Numbers quoted are medians. Average performance gains are higher because commands that take longer to execute are generally sped up more.

Stata/MP running on four cores runs in 50% (all commands) and 35% (estimation commands) of the time required by Stata/SE. Both numbers are median measures.

Stata/MP supports up to 64 cores.

Stata/IC is a slower than Stata/SE, but those differences emerge only when processing datasets that are pushing the limits of Stata/IC. Stata/SE has a larger memory footprint and uses that extra memory for larger look-aside tables to more efficiently process large datasets. The real benefits of the larger tables become apparent only after exceeding the limits of Stata/IC. Stata/SE was designed for processing large datasets.

In all cases, the differences are all technical and internal. From the user's point of view, Stata/MP, Stata/SE, and Stata/IC work the same way.

5.5 Feature comparison of Stata/MP, SE, and IC

The features of all flavors of Stata on all platforms are the same. The differences are in speed and in limits. The differences in limits are

Stata/IC Stata/SE and /MP Parameter | Default min max | Default min max -----------+-------------------------+---------------------------- maxvar | 2,048 2,048 2,048 | 5,000 2,048 120,000 (MP) | | 32,767 (SE) | | matsize | 400 10 800 | 400 10 11,000 | | processors | 1 1 1 | 2 1 64 (MP) | | 1 1 1 (SE) ------------------------------------------------------------------ Note: The default number of processors for Stata/MP is the minimum of processors licensed and processors available.

The limits on Stata/MP and /SE are settable. You reset the limits temporarily by typing

. set maxvar # . set matsize # . set processors #

Concerning the last, Stata/MP users sometimes want to use fewer processors to leave some free for other applications.

You reset the limits permanently by typing

. set maxvar #, permanently . set matsize #, permanently

If you use Stata/SE or Stata/MP, see help stata/se or help stata/mp to learn more.


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