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| author | Johnathan Corgan <johnathan@corganlabs.com> | 2017-06-27 13:28:58 -0700 |
|---|---|---|
| committer | Johnathan Corgan <johnathan@corganlabs.com> | 2017-06-27 13:28:58 -0700 |
| commit | d725f978a4cf21f5a9fc3dd4e02c2b7753c683d2 (patch) | |
| tree | f8ac162459aafef8b051376fdb41b41594435314 /gr-fft | |
| parent | 54e89c6431c249bbe560568d76800fef6a245506 (diff) | |
| parent | 4a7c612bdebe268cacd60cf137252c5d1753a701 (diff) | |
Merge branch 'maint'
Diffstat (limited to 'gr-fft')
| -rw-r--r-- | gr-fft/lib/window.cc | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/gr-fft/lib/window.cc b/gr-fft/lib/window.cc index 126b28978d..cfbdb93dbd 100644 --- a/gr-fft/lib/window.cc +++ b/gr-fft/lib/window.cc @@ -261,10 +261,19 @@ namespace gr { double inm1 = 1.0/((double)(ntaps-1)); double temp; - for(int i = 0; i < ntaps; i++) { + /* extracting first and last element out of the loop, since + sqrt(1.0-temp*temp) might trigger unexpected floating point behaviour + if |temp| = 1.0+epsilon, which can happen for i==0 and + 1/i==1/(ntaps-1)==inm1 ; compare + https://github.com/gnuradio/gnuradio/issues/1348 . + In any case, the 0. Bessel function of first kind is 1 at point 0. + */ + taps[0] = IBeta; + for(int i = 1; i < ntaps-1; i++) { temp = 2*i*inm1 - 1; taps[i] = Izero(beta*sqrt(1.0-temp*temp)) * IBeta; } + taps[ntaps-1] = IBeta; return taps; } |