Hi Steve,

Thanks a lot for this new version! It runs great on my Red Pitaya board.

Following your suggestions, I've added the -C 5000 option and removed 
the -w option. Each of these changes reduced the decoding time by 22-25%.

Now I can run the WSPR decoding in less than half time than before.

Best regards,

Pavel

Steven Franke wrote:
> Hi Pavel and all -
>
> I spent some time this weekend to check out your patch to the experimental 
> wspr decoder. I was able to confirm your observation of a worthwhile speedup 
> on my Intel cpu.
>
> I also did some more tests to compare the patched wsprd_exp with the stock 
> decoder wsprd. These tests showed that wsprd_exp produced more good decodes 
> but also more false decodes than wsprd. I found that raising the metric-table 
> bias to 0.45 from 0.42 lowered the false-decode rate of wsprd_exp to the same 
> level as that of the current wsprd. Even with this change, wsprd_exp still 
> produces more decodes than wsprd.
>
> After making the changes described above I did a final set of runs on three 
> different batches of files. For each run I recorded the number of good 
> decodes, the number of bad decodes containing a “/“ because those are easy to 
> find and count, and total execution time from wspr_timer.out.
>
> The results are summarized below in this order:
> sF: wsprd                                      (Fano algorithm, max 10000 
> cycles)
> eF: wsprd_exp                              (Fano algorithm, max 10000 cycles)
> eJ: wsprd_exp -JC 5000               (Jelinek algorithm, max 5000 cycles)
>
> In the following, the number in parentheses is the number of bad decodes that 
> contain “/“ (because these are easy to find and count):
>
> 1. k9an wav files from 8-channel SDR - 1953 files, all bands
> sF: 5080 (1), 984s
> eF: 5162 (0), 862s
> eJ: 5160 (1), 811s
>
> 2. k9an c2 files from TS-480 - 258 files, all bands
> sF: 1132 (0), 165s
> eF: 1144 (0), 150s
> eJ: 1141 (0), 137s
>
> 3. k1jt wav files - 410 files
> sF: 2655 (0), 329s
> eF: 2728 (0), 319s
> eJ: 2718 (0), 300s
>
> In view of the fact that wsprd_exp is faster than wsprd, produces more 
> decodes than wsprd, and maintains the low false-decode rate of wsprd, I have 
> committed a change that makes the patched (float) version of wsprd_exp.c the 
> default decoder. The default setting is to use the Fano-algorithm for 
> decoding. The command-line setting -J can be used to switch to the Jelinek 
> stack-bucket decoder.
>
> This change has been committed as r6572.  I should note that I also took this 
> opportunity to fix a long-standing inconsistency in the way that the 
> time-offset, dt, has been reported by the wspr decoders. Until now, the 
> decoders have all reported the time offset relative to 2 seconds after the 
> beginning of the file. Since wspr transmissions start at 1 second after the 
> minute, the dt has traditionally been reported as -1 seconds for a 
> transmitter-receiver pair with the same clock time.
>
> Beginning with r6582, the dt is reported relative to 1 second after the 
> beginning of the file, and should be near zero for a transmitter-receiver 
> pair with the same clock time.
>
> Steve k9an
>
>


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