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http://www.hyphy.org/cgi-bin/hyphy_forums/YaBB.pl HYPHY Package >> HyPhy feedback >> random seed http://www.hyphy.org/cgi-bin/hyphy_forums/YaBB.pl?num=1169556793 Message started by wdelport on Jan 23^rd, 2007 at 4:53am

Title: random seed
Post by wdelport on Jan 23^rd, 2007 at 4:53am

Hi, I presume the RANDOM_SEED is being set to the system clock when SetParameter is not used? Is there a need to use a Randomise command? thanks ./w

Title: Re: random seed
Post by Sergei on Jan 23^rd, 2007 at 9:43am

Yes, indeed; the default seed is the system clock (seconds since Jan 1st 1970). Because of the properties of good random number generators (e.g. the Mersenne twister used by HyPhy), the closeness of two seeds imparts no undue similarity to the pseudorandom number sequences genereates from the two seeds and the period of the sequence is enormous (>2^10000), hence there should be no need to select the initial seed carefully.

Cheers,
Sergei