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sfmt-erlang: SIMD-oriented Fast Mersenne Twister (SFMT) for Erlang
Erlang C Other

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sfmt-erlang: SIMD-oriented Fast Mersenne Twister (SFMT) for Erlang

  • Version 0.3.3_RELEASE 16-JUL-2010
  • Edited and written by Kenji Rikitake (Kyoto University)
  • Email contact:

Copyright (c) 2010 Kenji Rikitake and Kyoto University. All rights reserved.

Copyright (c) 2006,2007 Mutsuo Saito, Makoto Matsumoto and Hiroshima University. All rights reserved.

See LICENSE.txt for the license (new/simplified BSD license). (Note: license of rebar is Apache 2.0 License.)

This software is based on SFMT ver. 1.3.3 (SIMD oriented Fast Mersenne Twister(SFMT)) by Mutsuo Saito (Hiroshima University) and Makoto Matsumoto (Hiroshima University)

Details of SFMT algorithm


C NIFs based on SFMT 1.3.3 added from 0.3.0_RELEASE

  • reference: sfmt-extstate at
  • see c_src/sfmt_nif.[ch] for the details
  • speedup: ~40 times faster than the pure Erlang code (when fully inline-optimized (see rebar.config))
  • Pure Erlang code available under reference_texts/
  • gen_rand32/1 and gen_rand_float/1 use Erlang lists (Dan Gudmudsson showed the list version is faster)
  • NOTE: SSE2 code and options removed due to causing crash of Erlang BEAM (and even if the code enabled the performance increase is minimal)

Tested platforms

  • FreeBSD/i386 7.3-RELEASE with Erlang/OTP R14A
  • RedHat Enterprise Linux AS V4 of x86_64 with Erlang/OTP R14A (on the Thin Cluster of the Kyoto University ACCMS Supercomputer System)


  • Use GNU make and then

    make compile

(Note: on FreeBSD, GNU make should be invoked as gmake.)

The build script is Basho's rebar at (which requires Erlang/OTP to run)

API compatible with the random module

seed0, seed/0, seed/3, uniform/0, uniform/1, uniform_s/1, uniform_s/3 

Refactoring note of the pure-Erlang code

  • Rewriting ++ (append) operators by ring buffer loops (as a pair of lists consuming the head elements, and the corresponding accumulators) made the code ~50% faster


  • Documentation
  • NIF reload/upgrade/upload code fix; not yet fully tested

Code authors:

  • Mutsuo Saito
  • Makoto Matsumoto
  • Kenji Rikitake
  • Dan Gudmundsson


  • Dave "dizzyd" Smith
  • Tuncer Ayaz
  • Tim Bates (random_mt.erl implementation of Mersenne Twister)
  • Dan Gudmundsson


During the compatibility test of this software, Kenji Rikitake used the supercomputer service provided by Academic Center for Computing and Media Studies (ACCMS), Kyoto University.

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