Re: [Discuss-gnuradio] Error in Interpolating FIR filter

[Tom Rondeau]

On Fri, Apr 5, 2013 at 1:01 PM, Manu T S <address@hidden> wrote:
> Thanks everyone.
>
> It worked when I set the taps. I was confused because from what I remember I
> have used these blocks previously without specifying the taps.
>
> I also noticed that if I use a polyphase resampler instead of interpolating
> filter, the scope does not pope up. It just says excuting and then done. It
> didn't through any error. Again it worked when I set the taps.

I have a patch for that error. Will hopefully push it today.

Tom


> On Fri, Apr 5, 2013 at 7:26 PM, Tom Rondeau <address@hidden> wrote:
>>
>> On Fri, Apr 5, 2013 at 9:01 AM, Brian Padalino <address@hidden>
>> wrote:
>> > On Fri, Apr 5, 2013 at 8:29 AM, Tom Rondeau <address@hidden> wrote:
>> >>
>> >> On Fri, Apr 5, 2013 at 1:31 AM, Manu T S <address@hidden> wrote:
>> >> > Executing the attached flow graph I get the following error.
>> >> >
>> >> >
>> >> >
>> >> > #####################################################################################
>> >> >>>> gr_fir_ccc: using SSE
>> >> > Traceback (most recent call last):
>> >> >   File "/home/manu/coding/top_block.py", line 72, in <module>
>> >> >     tb.Run(True)
>> >> >   File
>> >> >
>> >> >
>> >> > "/usr/local/lib/python2.7/dist-packages/grc_gnuradio/wxgui/top_block_gui.py",
>> >> > line 76, in Run
>> >> >     self.start()
>> >> >   File
>> >> > "/usr/local/lib/python2.7/dist-packages/gnuradio/gr/top_block.py",
>> >> > line 97, in start
>> >> >     self._tb.start(max_noutput_items)
>> >> >   File
>> >> >
>> >> >
>> >> > "/usr/local/lib/python2.7/dist-packages/gnuradio/gr/gnuradio_core_runtime.py",
>> >> > line 3077, in start
>> >> >     return _gnuradio_core_runtime.gr_top_block_sptr_start(self,
>> >> > max_noutput_items)
>> >> > RuntimeError: gr_buffer_add_reader: nzero_preload must be >= 0
>> >> >
>> >> >
>> >> > #######################################################################################
>> >> >
>> >> > What could be the possible reason?
>> >> >
>> >> > I have installed using build-gnuradio script on day before yesterday.
>> >> >
>> >> >
>> >> >
>> >> > --
>> >> > Manu T S
>> >>
>> >> Manu,
>> >>
>> >> You have to give the interpolator taps. It can't run without a filter
>> >> defined.
>> >>
>> >
>> > The error message could definitely be much better.
>> >
>> >   "RuntimeError: gr_buffer_add_reader: nzero_preload must be >= 0"
>> >
>> > Even to an experienced person, without seeing the flow graph, that error
>> > doesn't mean anything.  Debugging a large flow graph might be like
>> > looking
>> > for a needle in a haystack.
>> >
>> > As a side note, what error gets thrown when this is in a straight C++
>> > application?  Is it more informative or equally as ambiguous?
>> >
>> > Is it possible to get the filter to throw the assertion/error versus the
>> > runtime?
>> >
>> > Brian
>>
>> I was wondering who was going to ask that question first. But that's
>> what I get for answering email before my coffee.
>>
>> Strangely, there is no error generated by the class for this case. I'm
>> adding one now. If no taps are provided, it will throw a runtime_error
>> that tells you a bit more what's going on.
>>
>> Tom
>
>
>
>
> --
> Manu T S