Error trying to load FFT filter taps

GNU Radio
1

Am getting the following error when trying to run a GRC flowgraph that
loads FFT filter taps from an external file. The type filter parameter
is
set to complex->complex (complex taps).
The flow graph has imported numpy. The taps are loaded using:

numpy.fromfile(’/home/tom/Desktop/EchoScreencaps/chirp-down-20-20-131072’,
numpy.complex64)

as the taps parameter. What does the error below mean?

GRC: v3.7.4git-101-g76970d54
Ubuntu 13.10
top_block.py is attached.

– Tom, N5EG

Traceback (most recent call last):
File “/home/tom/Desktop/EchoScreencaps/top_block.py”, line 173, in

tb = top_block()
File “/home/tom/Desktop/EchoScreencaps/top_block.py”, line 115, in
init
self.fft_filter_xxx_0 = filter.fft_filter_ccc(1,
(numpy.fromfile(’/home/tom/Desktop/EchoScreencaps/chirp-down-20-20-131072’,
numpy.complex64)), 1)
File
“/usr/local/lib/python2.7/dist-packages/gnuradio/filter/filter_swig.py”,
line 1329, in make
return _filter_swig.fft_filter_ccc_make(*args, **kwargs)
TypeError: in method ‘fft_filter_ccc_make’, argument 2 of type
‘std::vector< gr_complex,std::allocator< gr_complex > > const &’

2

On Sat, Apr 19, 2014 at 1:27 PM, Tom McDermott [email protected]
wrote:

GRC: v3.7.4git-101-g76970d54
File “/home/tom/Desktop/EchoScreencaps/top_block.py”, line 115, in

Tom,

This is a conflict between the numpy array data type and swig. Call the
.tolist() function on the array passed back from numpy and it should
work.

Tom

3

Thanks, Tom that solved the problem.

numpy.fromfile(‘filename’, numpy.complex64).tolist()

Should the gnuradio wiki (GRC) text be updated?

Apologies for the triple posting, first two attempts were using
yahoo.commail account, got
bit by the yahoo DMARC problem and dumped from the list. Changed to
gmail
to avoid the problem.

– Tom, N5EG

4

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Strange: For me, the problem persists (at least with random dummy data
from a random file in /tmp):

taps = numpy.fromfile(“/tmp/tblatex-4.png”,
dtype=numpy.complex64).tolist()
fffilter = filter.fft_filter_ccc(1, taps ,1)
Traceback (most recent call last):
File “”, line 1, in
File
“/home/marcus/.usrlocal/lib64/python2.7/site-packages/gnuradio/filter/filter_swig.py”,
line 1329, in make
return _filter_swig.fft_filter_ccc_make(*args, **kwargs)
TypeError: in method ‘fft_filter_ccc_make’, argument 2 of type
‘std::vector< gr_complex,std::allocator< gr_complex > > const &’

Greetings,
Marcus

On 20.04.2014 18:24, Tom McDermott wrote:

– Tom, N5EG

Am getting the following error when trying to run a GRC
flowgraph that loads FFT filter taps from an external file. The
type filter parameter is set to complex->complex (complex
taps). The flow graph has imported numpy. The taps are loaded
using:

numpy.fromfile(‘/home/tom/Desktop/EchoScreencaps/chirp-down-20-20-131072’,

numpy.complex64)

“/home/tom/Desktop/EchoScreencaps/top_block.py”, line 173, in
tb = top_block() File
“/home/tom/Desktop/EchoScreencaps/top_block.py”, line 115, in
init self.fft_filter_xxx_0 = filter.fft_filter_ccc(1,
(numpy.fromfile(‘/home/tom/Desktop/EchoScreencaps/chirp-down-20-20-131072’,

numpy.complex64)), 1)

File
“/usr/local/lib/python2.7/dist-packages/gnuradio/filter/filter_swig.py”,

line 1329, in make

Call the .tolist() function on the array passed back from numpy
Discuss-gnuradio Info Page

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5

On Sun, Apr 20, 2014 at 12:24 PM, Tom McDermott [email protected]
wrote:

– Tom, N5EG

Absolutely update the wiki page with helpful tips like this. Which page
in
particular are you referring to?

Tom