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Editing DF2014 Talk:Advanced world generation
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I wanted to know how many useful bits of entropy a seed value provides. Without the source code the best I can do is make an inference based on the character set used to encode [https://steamcommunity.com/app/975370/discussions/0/3716062978736953784/ seeds stored in <code>gamelog.txt</code>] (e.g. <code>i90kKcEwt1DqUZNL5Bvy</code>). Using [http://waterlan.home.xs4all.nl/dos2unix.html <code>dos2unix</code>] to use Unix-style line endings and [https://www.johndcook.com/blog/2019/10/16/file-character-counts/ <code>fold</code>, <code>sort</code>, and <code>uniq</code>] to produce a character frequency count of a few dozen seeds, the seeds seem to use a <code>[a-zA-Z0-9]</code> character set (62 characters). Each seed is 20 characters long, meaning it encodes <code>l(62^20)/l(2)=119.08</code> bits of entropy. That means theoretically, the PRNG has access to, at most, 119 bits of entropy; the next question is: '''how many bits of entropy does the PRNG actually make use of from a typed string I provide'''? I ask since I'd like to save myself time in typing random seeds; if the PRNG uses only 32 bits of state, then I'd only need to input 5 <code>[a-zA-Z0-9]</code>characters (e.g. <code>i90kK</code>). [[User:Baltakatei|Baltakatei]] ([[User talk:Baltakatei|talk]]) 05:37, 23 December 2022 (UTC) | I wanted to know how many useful bits of entropy a seed value provides. Without the source code the best I can do is make an inference based on the character set used to encode [https://steamcommunity.com/app/975370/discussions/0/3716062978736953784/ seeds stored in <code>gamelog.txt</code>] (e.g. <code>i90kKcEwt1DqUZNL5Bvy</code>). Using [http://waterlan.home.xs4all.nl/dos2unix.html <code>dos2unix</code>] to use Unix-style line endings and [https://www.johndcook.com/blog/2019/10/16/file-character-counts/ <code>fold</code>, <code>sort</code>, and <code>uniq</code>] to produce a character frequency count of a few dozen seeds, the seeds seem to use a <code>[a-zA-Z0-9]</code> character set (62 characters). Each seed is 20 characters long, meaning it encodes <code>l(62^20)/l(2)=119.08</code> bits of entropy. That means theoretically, the PRNG has access to, at most, 119 bits of entropy; the next question is: '''how many bits of entropy does the PRNG actually make use of from a typed string I provide'''? I ask since I'd like to save myself time in typing random seeds; if the PRNG uses only 32 bits of state, then I'd only need to input 5 <code>[a-zA-Z0-9]</code>characters (e.g. <code>i90kK</code>). [[User:Baltakatei|Baltakatei]] ([[User talk:Baltakatei|talk]]) 05:37, 23 December 2022 (UTC) | ||
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