Actually, SRFI 27 specifies repeatable random sources. You have to call random-source-randomize! to get different ones. And, there is a random-source-pseudo-randomize! procedure that gives you multiple, independent, repeatable random sources. There are also routines in the science collection to create vectors of independent random sources.
<br><br>Doug<br><br><div class="gmail_quote">On Jan 2, 2008 10:21 AM, Chongkai Zhu <<a href="mailto:czhu@cs.utah.edu">czhu@cs.utah.edu</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="Ih2E3d">Erich Rast wrote:<br>> Hi,<br>><br>> Sorry, I know this is a bit off-topic, but perhaps someone here has<br>> already stumbled across the answer. I'm looking for a good PRNG that<br>> is portable, but it needs to be one that allows me to get exactly the
<br>> same PRN sequence from the same seed.<br>><br>> Can I use SRFI-27 for that purpose or does it only specify the<br>> interface to possibly different PRNGs that might produce different<br>> sequences?<br>
><br><br></div>SRFI-27 only specifies the interface to possibly different PRNGs that<br>might produce different sequences. But the reference implementation of<br>SRFI 27 is portable and allows you to get exactly the same PRN sequence
<br>from the same seed.<br><div class="Ih2E3d"><br>> How about the built-in generator of MzScheme, might it change in<br>> future or is it part of the specs that it won't change under the hood?<br>><br><br></div>
Matthew just changed the built-in generator of MzScheme, as a result of<br>a discussion here a few days ago. The SRFI 27 implementation in SVN<br>(v399) is build on top of the built-in generator, and produces the same<br>
sequence as the reference implementation of SRFI 27.<br><br>> Best,<br>><br>> Erich<br>><br><font color="#888888">Chongkai<br></font><div><div></div><div class="Wj3C7c"><br>_________________________________________________
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