{"id":33709,"date":"2023-02-12T19:16:18","date_gmt":"2023-02-12T13:46:18","guid":{"rendered":"https:\/\/jassweb.com\/solved\/solved-how-to-improve-the-uniformly-distributed-of-a-given-random-function-to-generate-uniformly-distributed-numbers-closed\/"},"modified":"2023-02-12T19:16:18","modified_gmt":"2023-02-12T13:46:18","slug":"solved-how-to-improve-the-uniformly-distributed-of-a-given-random-function-to-generate-uniformly-distributed-numbers-closed","status":"publish","type":"post","link":"https:\/\/jassweb.com\/solved\/solved-how-to-improve-the-uniformly-distributed-of-a-given-random-function-to-generate-uniformly-distributed-numbers-closed\/","title":{"rendered":"[Solved] How to improve the uniformly distributed of a given random function to generate uniformly distributed numbers? [closed]"},"content":{"rendered":"

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what can be improved on a given random function to make it more random or for a bigger range or something else?<\/p>\n

and therefore no SRANDOM can be used up to now.<\/p>\n

How to improve the randomness of the fuction above, if possible ?<\/p>\n<\/blockquote>\n

Sooo write your own SRANDOM with your own semantics. Ex:<\/p>\n

srandom() {\n   # take random number from \/dev\/urandom\n   # we take only just 4 bytes - one 2^32 number\n   printf \"%d\\n\" \"0x$(\n       dd if=\/dev\/urandom of=\/dev\/stdout bs=4 count=1 status=none |\n       xxd -p)\"\n}\n<\/code><\/pre>\n
and then:<\/p>\n
normalize_value(){\n   ...\n   rnd=$(srandom)\n   rnd_count=$((rnd \/ ...))\n}\n<\/code><\/pre>\n
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Accepting a wider range of numbers<\/p>\n<\/blockquote>\n
If you are not happy with the way shell arithmetic expansion works, then… use a different tool. bc<\/code> calculator has unlimited range.<\/p>\n
rnd_count=$(echo \"\n     # see https:\/\/superuser.com\/questions\/31445\/gnu-bc-modulo-with-scale-other-than-0\n     scale=0; \n     # super big random number from three 2^32 numbers\n     rnd = $(srandom) * 2^(32*2) +  $(srandom) * 2^32 + $(srandom)\n     rnd % ($max - $min + 1) + $min\n     \" | bc)\n<\/code><\/pre>\n
You can write your own C program with getrandom()<\/code> and compile it on the fly echo \"int main() { stuff(); }\" | gcc -xc - && .\/a.out; rm .\/a.out<\/code> basically granting you any semantics you want. There are also other scripting languages, like perl, python, ruby, all most probably with their own big-number libraries and urandom number generation implementations. Sky the limit.<\/p>\n
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Every improvement should use bash only.<\/p>\n<\/blockquote>\n
Is from my perspective a pointless limitation – overall, I am paid for results, not really “how” I solve problems. Anyway, you could, giving you a bunch of ideas how to proceed:<\/p>\n