Re: Maximum Number of Bins

[Marcus D Leech]

Sharing your flow-graph. The exact error messages and more context would be good

Presumably you’re talking about FFT bins but it’s not clear. 

Also why are your samples being conveyed as strings ?  That’s wildly 
inefficient. 

Sent from my iPhone

> On Oct 28, 2020, at 7:24 PM, Criss Swaim <cswaim@tpginc.net> wrote:
> 
> I am working on a new application of gnuradio that pushes the
> limits--satellite-based detection of RF from rotating
> magnetized-quark-nugget dark matter transiting through the
> magnetosphere--and need as many bins as possible to reduce the
> background noise per frequency channel.
> 
> I have successfully run with 2 million bins, but when I jump to 3
> million bins, the application abends with a segment fault.  I have
> deconstructed the following python line in a custom python block that is
> failing:
> 
>> raw_samps = numpy.fromstring(self._msgq.delete_head().to_string(), 
>> numpy.float32)
> 
> and the failure is occurring while trying to convert the results from
> the delete_head() to a string (to_string()).   Any reference to the
> result of the delete_head() functions results in an error.
> 
> the _msgq is defined as _msgq = gr.msg_queue(MSGQ_LIMIT) where the
> MSGQ_LIMIT = 2
> 
> Here is the refactored code:
> 
>> # refactor raw_samps line test_str = self._msgq.delete_head()
>> print("bin_sub_avg::got msg "
>> sys.stdout.flush() 
>> print(test_str)
>> sys.stdout.flush() test_string = test_str.to_string()
>> print("bin_sub_avg::converted msg to string") 
>> sys.stdout.flush()
>> raw_samps = numpy.fromstring(test_string, numpy.float32)
>> print("bin_sub_avg::converted from string to numpy array")
>> sys.stdout.flush()
> 
> The output is:
> 
> bin_sub_avg::got msg 
> "the object for the shared pointer - test_str" (I did not save the exact 
> message)
> 
> Then the application aborts.
> 
> Is there a limit on the number of bins gnuradio can handle?
> 
> Any thoughts on how to find the cause or limit?
> 
> -- 
> Criss Swaim
> cswaim@tpginc.net
> cell: 505.301.5701
> 
>