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. On Fri, Apr 5, 2013 at 7:26 PM, Tom Rondeau <[email protected]> wrote: > On Fri, Apr 5, 2013 at 9:01 AM, Brian Padalino <[email protected]> > wrote: > > On Fri, Apr 5, 2013 at 8:29 AM, Tom Rondeau <[email protected]> wrote: > >> > >> On Fri, Apr 5, 2013 at 1:31 AM, Manu T S <[email protected]> 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
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