Re: [Discuss-gnuradio] speeding up elementary functions: constraints

[Matt Ettus]

Patrick Strasser wrote:
> Hello!
>
> Following the discussion about Intel libraries[0] and sse 
> optimization[1], I did some literature recherche about elementary 
> functions (trigonometric functions, log, exp). In particular I hope to 
> find some clever methods to speed up atan and sin/cos, which would be 
> very handy for all the FM stuff. But I need some parameters to find 
> useful methods:

I think that having a family of speedups for common operations would be 
nice.  We can categorize them as to accuracy so that you can choose the 
real operation if you can't tolerate reduced accuracy.  Also, it is 
almost never necessary for us to have full double precision operations.  
We almost always use single precision and often that is overkill.

Here are a few quick tips I found looking around, which might be useful 
for gnuradio:

http://www.dspguru.com/comp.dsp/tricks/alg/sincos.htm
http://www.dspguru.com/comp.dsp/tricks/alg/mag_est.htm
http://www.dspguru.com/comp.dsp/tricks/alg/mag_est2.htm
http://www.dspguru.com/comp.dsp/tricks/alg/fxdatan2.htm
http://www.dspguru.com/comp.dsp/tricks/alg/dc_block.htm
http://www.dspguru.com/comp.dsp/tricks/alg/quicklog.htm

Matt