ronggui wrote: > set.seed is used to set the random number seed. > When we use functions ,say runif, to generate random number ,we almost > get different set of random number.
> As for what the i in set.seed(i) should be,I don't think it is a serious > matter. The help for set.seed tells you all you need to know. 'i' must be a single value "interpreted as an integer". You can give it a decimal number, but it makes it an integer: > set.seed(pi) > runif(2) [1] 0.1680415 0.8075164 > set.seed(3) > runif(2) [1] 0.1680415 0.8075164 But not too big an 'integer': > set.seed(1e100) Error in set.seed(1e+100) : supplied seed is not a valid integer In addition: Warning message: NAs introduced by coercion because 1e100 isn't represented as an integer internally (in C/Fortran code, its a 'float' or'double precision' type of thing. For me it takes signed 32 bit integers, so the limits are +/- 2147483647: > set.seed(2147483647) > set.seed(-2147483647) > set.seed(-2147483648) Error in set.seed(-2147483648) : supplied seed is not a valid integer In addition: Warning message: NAs introduced by coercion > set.seed(2147483648) Error in set.seed(2147483648) : supplied seed is not a valid integer In addition: Warning message: NAs introduced by coercion A 32 bit integer gives you over 4 billion possible random sequences. Is that enough? Barry ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
