in reply to Convert arithmetic expression from Excel to Perl syntax

^ doesn't mean "to the power of" in Perl, it means "exclusively ored with". Change $temp^2 to $temp*$temp and $vol^2 to $vol*$vol.

Update: As other pointed out, Perl does have a power operator: ** (although it's not quite as fast, as you can see in Benchmarks I posted below).

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Re^2: Convert arithmetic expression from Excel to Perl syntax
by throttle (Beadle) on Nov 04, 2004 at 18:03 UTC
    You can also di $temp**2 or $vol**2. Exactly the same, but faster.
[reply]
      You're right that ** works too, but you're wrong about it being faster (at least on my system). 
      # srand(0) is used to make sure both
# subs are using the same input set.

sub m1 {
   unless ($i1) { srand(0); $i1=1; }
   $n = rand;
   $p = $n ** 2;
}

sub m2 {
   unless ($i2) { srand(0); $i2=1; }
   $n = rand;
   $p = $n * $n;
}


use Benchmark;
Benchmark::cmpthese(0, {
   '$n**2' => \&m1,
   '$n*$n' => \&m2,
});


__END__

           Rate $n**2 $n*$n
$n**2  722292/s    --  -29%
$n*$n 1013884/s   40%    --

      [download]
[reply]
[d/l]
        when i said it was faster i meant that 'writing it' is faster
[reply]

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