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Re: [TCLUG:12095] Powers in Perl



pow10(x) = exp(log(10) * x)

Tom Veldhouse
veldy@visi.com

----- Original Message ----- 
From: "Mike Hicks" <hick0088@tc.umn.edu>
To: <tclug-list@mn-linux.org>
Sent: Monday, January 10, 2000 8:19 PM
Subject: [TCLUG:12095] Powers in Perl


> I have a little chunk of code below (taken pretty much verbatim from a C
> program) for calculating relative humidity using the current temperature
> and dewpoint (in degrees C)  The problem is that I need a function that
> will do powers of 10, but Perl (the language I'm writing this little
> program in) only has exp() for raising e to a power (as far as I know)
> 
> Does anyone either know a good trick to use or a function that I may
> have missed?  Thanks
> 
>     {
>       my ($esat, $esurf, $temp, $dewp)
>       $temp = $self->{C_TEMP};
>       $dewp = $self->{C_DEW};
>       
>       $esat = 6.11 * pow(10.0, (7.5 * $temp) / (237.7 + $temp)); 
>       $esurf = 6.11 * pow(10.0, (7.5 * $dewp) / (237.7 + $dewp));
>      
>       $self->{HUMIDITY} = sprintf("%3.f",(esurf/esat) * 100));
>     }
> 
> -- 
>  _  _  _  _ _  ___    _ _  _  ___ _ _  __   You're not Dave.  Who are 
> / \/ \(_)| ' // ._\  / - \(_)/ ./| ' /(__   you? 
> \_||_/|_||_|_\\___/  \_-_/|_|\__\|_|_\ __)                             
>  [ Mike Hicks | http://umn.edu/~hick0088/ | mailto:hick0088@umn.edu ]
> 
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