.\"
.\" Sccsid @(#)factor.1.in	1.5 (gritter) 8/18/03
.\" Parts taken from factor(1), Unix 7th edition:
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.TH FACTOR 1 "8/18/03" "Heirloom Toolchest" "User Commands"
.SH NAME
factor \- factor a number
.SH SYNOPSIS
\fBfactor\fR [\fInumber\fR]
.SH DESCRIPTION
When
.I factor
is invoked without an argument, it waits for a number to be typed in.
If you type in a positive
number less than 2\u\s7@@MANT_DIG@@\s0\d (about
.ie t @@EXP@@\(mu10\u\s7@@MNT@@\s0\d\|)
.el @@EXP@@e@@MNT@@)
it will factor the number and print its prime factors; each one is printed
the proper number of times.
Then it waits for another number.
It exits if it encounters a zero or any non-numeric character.
.PP
If
.I factor
is invoked with an argument, it factors the number
as above and then exits.
.PP
Maximum time to factor is proportional to
.ie t \(sr\o'\fIn\fR\(rn'
.el sqrt(n)
and occurs when
.I n
is prime
or the square of a prime.
.\"It takes 1 minute to factor a prime
.\"near
.\"10\u\s714\s0\d
.\"on a PDP11.
.SH DIAGNOSTICS
`Ouch.' for input out of range or for garbage input.