Calculating Nth root using perl.

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Calculating Nth root using perl. by kvale (Monsignor) on May 09, 2006 at 18:01 UTC
`$n = 4; $ans = $arg**(1/$n);` [download] -Mark	[reply] [d/l]
Re: Calculating Nth root using perl. by salva (Canon) on May 09, 2006 at 18:19 UTC
for the 4th root you can also use: `my $r4 = sqrt sqrt $num;` [download]	[reply] [d/l]
Re^2: Calculating Nth root using perl. by QM (Parson) on May 09, 2006 at 22:54 UTC
++ Reminds me of the joke about the carpenter who threw half the nails out, because they were facing the wrong way! -QM -- Quantum Mechanics: The dreams stuff is made of	[reply]
Re: Calculating Nth root using perl. by Fletch (Bishop) on May 09, 2006 at 18:04 UTC
Depending on the precision you need, log and exp may be all you need. If you need larger numbers you may need to call in Math::BigFloat or the like.	[reply]
Re: Calculating Nth root using perl. by swampyankee (Parson) on May 09, 2006 at 18:02 UTC
Other than the snarky RTFM (Perl has an intrinsic exponentiation operator) `$x = $y (1/4) if $y > 0;` [download] This is the revised code, in response to salva's and ikegami's comments `if($y >= 0){ $x = $y (1/4); }else{ undef($x); die "Even roots of negative numbers require complex arithmetic\n"; }` [download] While the 4th root of a negative number exists, I'm presuming you don't need to do complex arithmetic. If you do, you man want to check out Math::Complex, although it appears to be developmental. emc "Being forced to write comments actually improves code, because it is easier to fix a crock than to explain it. " —G. Steele	[reply] [d/l] [select]
Re^2: Calculating Nth root using perl. by salva (Canon) on May 09, 2006 at 18:31 UTC
your code is not going to generate any error when `$y < 0`. That's usually a very bad thing! Just `$x = $y ** (1/4);` [download] is better!	[reply] [d/l] [select]
Re^3: Calculating Nth root using perl. by ikegami (Patriarch) on May 09, 2006 at 18:34 UTC
I agree (++). Error handling shouldn't be removed without being replaced. Either handle it (by throwing an exception, displaying a warning, returning a complex number, returning an error code, etc) or let Perl handle it (by dying).	[reply]