http://www.perlmonks.org?node_id=418156


in reply to Code refactoring: simple trig, but it's been so long.

Evidently you feel more comfortable using degrees rather than radians but the conversion to and from radians<->degrees serves no real purpose. Just define: 

my $ninety_degrees = atan(1)*2;

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You will get a division by zero crash in the case where $x and $y = 0 as it will fall through your 'extreme cases'. You can remove the dependency on a module by using radians and using a function for atan() like: 

sub atan {
    return 0 if $_[0]==0;
    return $_[0] > 0 ?
         atan2(sqrt(1+$_[0]*$_[0]),sqrt(1+1/($_[0]*$_[0]))) :
        -atan2(sqrt(1+$_[0]*$_[0]),sqrt(1+1/($_[0]*$_[0])));
}

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cheers

tachyon

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Re^2: Code refactoring: simple trig, but it's been so long.
by revdiablo (Prior) on Dec 30, 2004 at 04:27 UTC
    Evidently you feel more comfortable using degrees rather than radians but the conversion to and from radians<->degrees serves no real purpose.

    Yeah, that was just out of habit. I noticed that the conversion between radians and degrees was pointless before I posted, but never got around to changing it to only radians.

    You will get a division by zero crash in the case where $x and $y = 0 as it will fall through your 'extreme cases'.

    Ah, I hadn't noticed that. Using Zaxo's code will eliminate that problem, though. Many thanks.

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