Re: [Discuss-gnuradio] error while making detector

There's already blocks that do energy calculation, so you really don't have to implement this yourself.
In fact, I wrote a short answer on a similar question just yesterday. The question there was how to add a method "get_bandpower" to a C++ block, so here's the excerpt from
http://stackoverflow.com/a/33901845/4433386
where I explained other ways than implementing this yourself:

Other than that, there's already blocks that can do what you want:

• Probe Avg Mag²: has a method level() which does the same as your get_bandpower (aside from the √(.) )
• Complex to Mag ⟶ Decimating FIR Filter ⟶ Probe Signal: does the √(Re²+Im²), before passing it on to a filter with 123 (that was just my arbitrary fixed length) taps of 1/length, and decimating it to one value every average. Result get send to the Signal Probe, which has a signal() method, which does what your get_bandpower does. CPU load of this is relatively small -- it's really just the magnitude finding for every sample, and then 123 real multiplications + 123 real additions per 123 samples,in the filter, all SIMD increased, so basically, less than 1 FMAC per sample.
• Complex to Mag ⟶ Moving Average ⟶ Probe Signal: Names say it all. Nothing magical here.

Best regards,
Marcus

On 25.11.2015 16:19, Yan Huang wrote:

Hi Marcus,

 

I have followed the URL you recommended, but  I want to use gnuradio to do energy detection , so I follow the howto infrastructure and want to learn more about  it by building a new block. Is there any suggestion about how to make anergy detection?

 

Thanks,

 

Yan

 

From: discuss-gnuradio-bounces+eexyh22=nottingham.ac.uk@gnu.org [mailto:discuss-gnuradio-bounces+eexyh22=nottingham.ac.uk@gnu.org] On Behalf Of Marcus Müller
Sent: 25 November 2015 15:10
To: discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] error while making detector

 

Hi Yan,

which tutorial exactly where you following (URL)?
I recommend using the Guided Tutorials for beginners; they are much better illustrated, and they don't need the sometimes broken howto infrastructure.
https://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorials

Best regards,
Marcus

On 25.11.2015 15:45, Yan Huang wrote:

Hey,

I'm a new to use gnuradio and USRP B210, now I want to generate my OOT module start with the example 'howto_detect', and I followed guided tutorial in gnuradio.org. But there are still some problems as follows.

 

[  6%] Building CXX object lib/CMakeFiles/gnuradio-howto.dir/howto_detect_ff_impl.cc.o
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:32:5: error: prototype for 'gr::howto::howto_detect_ff::sptr gr::howto::howto_detect_ff::make(float, int, int)' does not match any in class 'gr::howto::howto_detect_ff'
     howto_detect_ff::make(float pfa, int L, int samples)
     ^
In file included from /home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.h:24:0,
                 from /home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:26:
/home/mint/Documents/gr-howto/include/howto/howto_detect_ff.h:49:19: error: candidate is: static gr::howto::howto_detect_ff::sptr gr::howto::howto_detect_ff::make()
       static sptr make();
                   ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc: In constructor 'gr::howto::howto_detect_ff_impl::howto_detect_ff_impl(float, int, int)':
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:52:24: error: expression cannot be used as a function
               d_pfa(pfa), d_L(L), d_samples(samples))
                        ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:52:32: error: expression cannot be used as a function
               d_pfa(pfa), d_L(L), d_samples(samples))
                                ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:52:52: error: expression cannot be used as a function
               d_pfa(pfa), d_L(L), d_samples(samples))
                                                    ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc: In function 'float gr::howto::TracyWidom(float)':
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:71:46: error: 'printf' was not declared in this scope
 tw = 18*(pd - (17/75)); printf("a - %f\n", tw);
                                              ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:73:47: error: 'printf' was not declared in this scope
 tw = 8*(pd - (179/400)); printf("b - %f\n", tw);
                                               ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:75:53: error: 'printf' was not declared in this scope
 tw = (87/20)*(pd - (643/870)); printf("c - %f\n", tw);
                                                     ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:77:52: error: 'printf' was not declared in this scope
 tw = (16/5)*(pd - (287/320)); printf("d - %f\n", tw);
                                                    ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:79:52: error: 'printf' was not declared in this scope
 tw = (17/5)*(pd - (297/340)); printf("e - %f\n", tw);
                                                    ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:81:49: error: 'printf' was not declared in this scope
 tw = (5.2)*(pd - (0.813)); printf("f - %f\n", tw);
                                                 ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:83:53: error: 'printf' was not declared in this scope
 tw = (53/5)*(pd - (909/1060)); printf("g - %f\n", tw);
                                                     ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:85:48: error: 'printf' was not declared in this scope
 tw = 26*(pd - (593/650)); printf("h - %f\n", tw);
                                                ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:87:56: error: 'printf' was not declared in this scope
 printf ("wrong pfa value: it must be between 0 and 1\n");
                                                        ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc: In member function 'virtual int gr::howto::howto_detect_ff_impl::general_work(int, gr_vector_int&, gr_vector_const_void_star&, gr_vector_void_star&)':
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:141:9: error: 'gsl_matrix' was not declared in this scope
         gsl_matrix * hankel = gsl_matrix_alloc (lenght,d_L);
         ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:141:22: error: 'hankel' was not declared in this scope
         gsl_matrix * hankel = gsl_matrix_alloc (lenght,d_L);
                      ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:141:59: error: 'gsl_matrix_alloc' was not declared in this scope
         gsl_matrix * hankel = gsl_matrix_alloc (lenght,d_L);
                                                           ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:142:22: error: 'V' was not declared in this scope
         gsl_matrix * V = gsl_matrix_alloc (d_L,d_L);
                      ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:143:9: error: 'gsl_vector' was not declared in this scope
         gsl_vector * S = gsl_vector_alloc (d_L);
         ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:143:22: error: 'S' was not declared in this scope
         gsl_vector * S = gsl_vector_alloc (d_L);
                      ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:143:47: error: 'gsl_vector_alloc' was not declared in this scope
         gsl_vector * S = gsl_vector_alloc (d_L);
                                               ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:144:22: error: 'temp' was not declared in this scope
         gsl_vector * temp = gsl_vector_alloc (d_ L);
                      ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:144:47: error: 'd_' was not declared in this scope
         gsl_vector * temp = gsl_vector_alloc (d_ L);
                                               ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:147:36: error: 'gsl_matrix_set_zero' was not declared in this scope
         gsl_matrix_set_zero (hankel);
                                    ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:156:47: error: 'fopen' was not declared in this scope
             story = fopen("filestory.txt", "a");
                                               ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:159:60: error: 'gsl_matrix_set' was not declared in this scope
                     gsl_matrix_set (hankel, p, j, vett[p+j]);
                                                            ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:162:57: error: 'gsl_linalg_SV_decomp' was not declared in this scope
                 gsl_linalg_SV_decomp (hankel, V, S, temp);
                                                         ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:163:43: error: 'gsl_vector_get' was not declared in this scope
                 lmax = gsl_vector_get(S, 0);
                                           ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:167:79: error: 'fprintf' was not declared in this scope
                 fprintf(story, "%f - ratio=%f - soglia=%f\n ", mem, ratio, thr);
                                                                               ^
/home/mint/Documents/gr-howto/lib/howto_detect_ff_impl.cc:168:29: error: 'fclose' was not declared in this scope
                 fclose(story);
                             ^
make[2]: *** [lib/CMakeFiles/gnuradio-howto.dir/howto_detect_ff_impl.cc.o] Error 1
make[1]: *** [lib/CMakeFiles/gnuradio-howto.dir/all] Error 2
make: *** [all] Error 2

 

Any solution to sort an error will be appreciated.

 

Thanks a lot,

 

Yan

 

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