On 13/08/2014 16:37, Tom Rondeau wrote: > The version we have in there is much (MUCH) faster than the libm atan2 > function. So yes, we trade off a bit of error for a massive > computational gain. The error is very small from what I recall, expect > in a few instances (near 0 or near pi/2 or something like that). Having > a graph of the error somewhere would be helpful.
I think it depends on the point of view, for me it is a bit of computational gain for a massive error :) > The fast atan method we use is still faster than what we have in VOLK. I > remember testing this out myself, which included putting that code into > the constructor. However, take a look at this post: > > http://www.trondeau.com/blog/2012/2/17/volk-benchmarking.html I don't see anything specific to the atan2() and alignment there. > We see an improvement in speed of blocks by doing the alignment. > Actually, I think that all blocks should probably have their alignment > set whether or not they use VOLK. But that would be a lot of work to do > correctly with all of our blocks to make sure it's done right and is > actually giving us a benefit. But having test this one in particular, > no, I don't see any need to remove this code. I see. Probably a comment in the code mentioning this, to avoid other being puzzled, is in order here :) Cheers, Daniele _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
