This code is based on C-code described in Matsumoto and Nishimura's Mersenne Twister and the Harase and Kimoto MELG repository. The MELG-based classes, like the original C-code versions, provide various period lengths from 2⁶⁰⁷-1 to 2⁴⁴⁴⁹⁷-1.

This repository includes Eiffel classes for:

• RANDOMS_DEMO -- Root class for system randoms_demo.ecf
• TWISTER_32 -- 32-bit Mersenne Twister
• TWISTER_64 -- 64-bit Mersenne Twister

The MELG-type classes as well as the 64-bit Twister are based on MELG which contains all the functionality for the generators of various period lengths:

• MELG_607
• MELG_1279
• MELG_2281
• MELG_4253
• MELG_11213
• MELG_19937
• MELG_44497

To conform to Eiffel's command-query separation principle, these classes depart from the paradigm used in the C versions.

1. Getting a random number does not advance the state (i.e. calling item multiple times returns the same random number).
2. State advancement (i.e. moving to the next random number) is in feature forth which calls the non-exported feature twist.
3. "Tempering" is handled in feature forth.

The demo program RANDOMS_DEMO uses TWISTER_32_TESTS, TWISTER_64_TESTS, and MELG_TESTS to display feature calls and the results of the calls. It also verifies the output against files produced by the original C files. When the demo system is open in EiffelStudio, you can also execute some features in AutoTest.