Re: Module Proposal: Math::Log

[Ken Williams]

On Saturday, February 1, 2003, at 10:15  AM, Salvador Fandi�o wrote:

Hi

By the way - here is my version. Just store it in some $PERL5LIB/Math/Log10.pm:
sub log10
{
return log(shift)/log(10);
}
1;

If speed is what you want, then

  use constant ILOG10 => 0.434294481903252; # 1.0/log(10.0)

  sub log10 { ILOG10*log(shift) }

That doesn't do much good. Look at this one-liner:

% perl -MO=Deparse -e '$x = log($y)/log(10)'
$x = log($y) / 2.30258509299405;
-e syntax OK
%

This shows that perl does constant-folding on the log(10) at compile-time anyway.

or even use

  ILOG10*log($anything)

in your code without calling any sub

Yeah, that could help.

 -Ken