Complex arg-trig functions
Stephen Montgomery-Smith
stephen at missouri.edu
Wed Sep 19 03:48:43 UTC 2012
On 09/18/2012 01:19 AM, Bruce Evans wrote:
> On Mon, 17 Sep 2012, Stephen Montgomery-Smith wrote:
>> I don't think your code works. It should be ry = atan2f(2, -ay) / 2,
>> not ry = atan2f(2, ay) / 2.
>
> Only logically. As I explained, the negation makes no difference to the
> result, but of course takes longer, so I removed it.
No, they give different results. atan2(y,x) = Pi - atan2(y,-x) if y is
positive.
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