Re: IOS floating point performance
Re: IOS floating point performance
- Subject: Re: IOS floating point performance
- From: Thomas Wetmore <email@hidden>
- Date: Thu, 08 Aug 2013 11:01:05 -0400
p.s. Of course you don't have to call sin() and cos() for
every half degree when building these tables. You can take advantage
of how trig functions repeat in the four quadrants, and you can
take advantage of other inverse and pythagorean reationships
that exist between them. Even the initial table building
can be optimized.
Tom Wetmore
On Aug 8, 2013, at 10:53 AM, Thomas Wetmore <email@hidden> wrote:
> Returning strictly to the issue of trig performance. A solution I
> have used in the past is to initialize tables of trig functions,
> say by calling sin() and cos() for every half a degree, and then
> interpolating those tables, never calling sin() or cos() again.
> I did this 29 years ago on an Atari 520ST to simulate the solar
> system, and it worked well. You only need enough trig accuracy
> for graphics to plot to the correct pixels. It takes very few
> decimal places to get that accuracy.
>
> Tom Wetmore
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