EdelSys Consulting edelweiss at
Wed Aug 1 17:16:16 CDT 2001

Why not just use sprintf to round?  What kind of precision we
talking about here?

"Throw me a frickin' bone here, Scott"

  -- Doctor Evil

At 04:43 PM 8/1/01 -0500, you wrote:
>     Your code is fine - the problem is just that numbers (floating point
or otherwise) are stored in internal (binary) representation. The "extra
digits" that you see tacked on the end are a consequence of how a floating
point number is stored in binary format. The inconsistencies are compounded
when you perform arithmetic operations. If you really need long floats, use
Math::BigFloat. If it's precision you're worried about, check out
Math::FixedPrecision. Both will be slow (compared to "straight math
operations") due to overloading of arithmetic operators. Hope this helps.
>                         - Rob
>-----Original Message-----
>From: Thomas Whitney [mailto:whitneyt at]
>Sent: Wednesday, August 01, 2001 2:16 PM
>To: phoenix-pm-list at
>Subject: Re: Math
>Thanks Scott,
>Here is the problem I was having last year. Just ran it again same
problem. I am running on v5.6.0. I don't see anything wrong that I am doing.
>Script started on Thu Aug 17 15:57:29 2000
>peoblej at holodeck[148]: cat
>#!/usr/local/bin/perl -w
>use strict;
>my $result = 0.0;
>$result = 0.07 * 10000.0;
>printf "%40.35f\n", $result;
>peoblej at holodeck[149]:
> 700.00000000000011368683772161602973938
>peoblej at holodeck[150]: exit
>script done on Thu Aug 17 15:57:44 2000
>Scott Walters wrote:
>> Hey Tom,
>> Well, looking at Math::BigInt/BigFloat, they do everything in Perl by
>> unpacking into an array from a string... something in C or Perl
>> that minipulated it directly in its binary format would be much faster...
>> what problems were you having with perls built in operators? Overflow?
>> Precision? Don't know of anything offhand, and I assume you've searched
>> CPAN... If you wanted to use a C library, Doug just did a demo on
>> [what was that?] Embed, which makes it really easy to stick some C
>> right in middle of your Perl.
>> -scott
>> On Wed, 1 Aug 2001, Thomas Whitney wrote:
>> > Hi All,
>> >
>> > I am doing a lot of decimal arithmetic. I ran into problems using
perl's standard arithmetic. Right now I am using Math::BigFloat, but it
seems slow. Can anybody recommend a better module
>> >
>> > Thanks
>> > Tom
>> >
>> >

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