Hi all, The next paragraph gives a bit of context. If you are bored you can skip it and go directly to the technical question.
I use PicoLisp to implement a pedagogical language, directly embedded in PicoLisp. In an exercise about dices, I noticed a kind of similarity among the results of my students. Of course, that was because I didn't expose `seed`. Students were quite disappointed: «but if we want to make games?», but I was not since: 1) I knew about the `seed` fix, now in use (like this: `(seed (time))`, since my goal is not security); 2) I found it was interesting to be able to check the results of the students; 3) It is a nice starting point to talk about PRNGs. It even gave me a related idea (totally not interesting in a non pedagogical context): let the user choose the sequence of the numbers that will be «generated». This would be interesting to build exercises, or for the students to test with a precise sequence. Something like: (de my_rand (m n) # IF a special *list_of_numbers variable has elements # THEN return the car of *list_of_numbers and circular-shift it # ELSE return (rand m n) ) Now the question. I found discrepancies between PicoLisp: : (rand 1 1000) -> 1 : (rand 1 1000) -> 934 : (bye) And Ersatz : (rand 1 1000) -> 1 : (rand 1 1000) -> 967 : (bye) I tried to inspect the source for getting some explanation with no luck. PicoLisp https://code.google.com/p/picolisp/source/browse/src/big.c#1213 Ersatz: https://code.google.com/p/picolisp/source/browse/ersatz/fun.src#3325 Is there a reason for those different behaviours ? Last thing (mostly for Jon), I read that the PicoLisp generator is a 64-bit linear congruential random generator (both pil64 and pil32) with the multiplier 6364136223846793005. I'd like to implement this generator for EmuLisp. Any advice ? Any objection ? chri -- http://profgra.org/lycee/ (site pro) http://delicious.com/profgraorg (liens, favoris) https://twitter.com/profgraorg http://microalg.info -- UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe
