On Wed, Jul 26, 2006 at 11:08:25PM -0700, Eric Blossom wrote: > On Thu, Jul 27, 2006 at 12:47:46AM +0200, Jens Elsner wrote: > > Hello, > > > > I'd like to calculate the complex dot product with GNU Radio. > > > > Is there a way to do it faster that this? This correlation takes > > "ages"... > > You can probably repurpose the existing gr_fir_ccc.h code. > See gnuradio-core/src/lib/filter/gr_fir_ccc.h > It doesn't apply the conjugate, so you'll need to work that into your > b values. If you use gr_fir_ccc.h, you'll get hand-coded SIMD > assembler on x86 and x86-64, and generic C++ code on the rest. Thanks, I'll have a look at it.
> The set_taps operation is relatively expensive. For our purposes, we > expected it to be done infrequently. This allowed us to amortize the > cost of building multiple copies of the taps at different alignments. > This was required to take advantage of the 128-bit loads with SSE. I'm using guard interval cross correlation to synchronize the OFDM frame and to estimate the frequency offset. The correlation code is the bottle neck, and I guess anything will be faster than what I have now. Jens _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio