degrees and radians.

[Jim Richardson]

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On Mon, 06 May 2002 15:15:50 -0600,
 Fernando Pérez <fperez528 at yahoo.com> wrote:
> Raymond Hettinger wrote:
> 
>>> I am trying to get the math module to deal with degrees rather than
>>> radians. (that it deals with radians for the angular functions like
>>> sin() isn't mentioned in the docs, which was sort of an eyeopener :)  I
>>> can't find any info on doing this. I can convert from-to degrees in the
>>> code calling the function, but that's a bit clunky. Any pointers to an
>>> FM to R? :)
>> 
>> There is a patch for adding degree/radian conversions.
>> See http://www/python.org/sf/552452
> 
> Sorry to sound critical, but I doubt this will make it in (and I hope it 
> doesn't). Reason: bloat. Yes, it's only two functions, but still, bloat is 
> bloat. Plus, if you really need those conversions, it's less typing and more 
> efficient (no function call) to simply use a multiplicative constant:
> 
> In [7]: to_rad = pi/180
> 
> In [8]: to_deg = 1/to_rad
> 
> In [9]: sin pi/4
> ------> sin (pi/4)
> Out[9]: 0.70710678118654746
> 
> In [10]: sin 45*to_rad
> -------> sin (45*to_rad)
> Out[10]: 0.70710678118654746
> 
> In [11]: (pi/4)*to_deg
> Out[11]: 45.0
> 
> I realize you have good intentions, but I truly don't think that in this case 
> the benefits outweigh the cost. OTOH, one could add a comment in the 
> docstrings to the effect of 'trig functions expect arguments in radians', 
> since it does seem to cause confusion among newbies.
> 
> Cheers,
> 

Well, it was a lightbulb going off in my head when I finally figured out
*why* the numbers my code was giving me were so wrong. Doh! after I
thought about it, it made perfect sense, but before I had thought about
it :)....

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-- 
Jim Richardson
	Anarchist, pagan and proud of it
http://www.eskimo.com/~warlock
Linux, from watches to supercomputers, for grandmas and geeks.