bramley.m@pg.com
Fri, 11 Sep 1998 10:27:00 -0400


Frank,

Actually, I think you want to use ceiling() instead of trunc(), as the latter
returns an integer too small to return all prime divisors, eg: factorize(6)
returns 1 2 6. But I was originally responding to Bill Venebles 'supplemental
exercise' to write a fn() that would return *all* of the divisors of an integer,
not just the prime ones.

Michael Bramley

______________________________ Reply Separator _________________________________
Subject: Re: Re[4]: [S] factors (divisors ) of an integer
Author: (INTERNET)fharrell@virginia.edu at external
Date: 9/11/98 9:43 AM

How about doing most of the job with

factorize <- function(n)
{
p <- n/(w <- c(1:trunc(sqrt(n)),n))
w[trunc(p) == p]
}

------------------------------------------------------------------------------
-------------
Frank E Harrell Jr
Professor of Biostatistics and Statistics
Division of Biostatistics and Epidemiology
Department of Health Evaluation Sciences
University of Virginia School of Medicine
hesweb1.med.virginia.edu/biostatistics.html
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