Issue with Virtual Sink/Source

Hi,

We recently bought a new PC with some powerful specs. GNU Radio was
built
from the source and it seems to be installed fine. However, when I try
to
use the virtual sink and source blocks in my flow graph, I am getting
the
following error:

Traceback (most recent call last):
File “./test_skh.py”, line 595, in
tb = test_skh()
File “./test_skh.py”, line 486, in init
self.connect((self.virtual_source_0, 0),
(self.blocks_multiply_conjugate_cc_0, 0))
File
“/usr/local/lib/python2.7/dist-packages/gnuradio/gr/hier_block2.py”,
line 93, in getattr
return getattr(self._impl, name)
AttributeError: ‘top_block_sptr’ object has no attribute
‘virtual_source_0’

Once I replace the virtual blocks with direct connections, things work
just
fine. What is the cause for this problem and how to fix it?

Please note that on an older machine, GNU Radio was installed around a
month ago following the same procedure followed here, and the virtual
sink/source blocks work just fine.

Thank you.

Best regards,
Khalid

On 01/05/2015 11:57 AM, khalid.el-darymli wrote:

File “./test_skh.py”, line 486, in init
Once I replace the virtual blocks with direct connections, things work


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My guess is that this machine has GR installed from the official repos
as well, and you’re getting an old GR instance.

Hi,

I’m having the same issue as Khalid. I just updated my GNU Radio source
based installation on two different machines. On one of the machines I
previously had a source installation of gnuradio 3.7.4. This machine
runs
Linux Mint 17.1, the other machine runs Ubuntu 14.04. A flow graph
utilising virtual sources and sinks that ran fine under gnuradio and
gnuradio-companion 3.7.4 now throws up the same error as Khalid has
pointed
out, on both my Linux Mint and Ubuntu machines.

Anyone else seeing this behaviour? Any ideas?

Thanks

Cheers
Richard

On 6 January 2015 at 05:57, khalid.el-darymli [email protected]


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Thanks Johnathan for the update.
BTW, with the recent installation, I am also getting the following
warning
when running my GRC or the GRC-generated python script,

fft_impl_fftw: /home/ov/.gr_fftw_wisdom: Permission denied
fft_impl_fftw: /home/ov/.gr_fftw_wisdom: Permission denied
fft_impl_fftw: /home/ov/.gr_fftw_wisdom: Permission denied
.
.
.
fft_impl_fftw: /home/oceanview/.gr_fftw_wisdom: Permission denied

This warning is repeated in the terminal like 100 times before the
script
actually runs. I am not sure why?

Thanks.

Best regards,
Khalid

On Mon, Jan 12, 2015 at 10:21 PM, Johnathan C.
<[email protected]

Hi,

fft_impl_fftw: /home/oceanview/.gr_fftw_wisdom: Permission denied

This warning is repeated in the terminal like 100 times before the script
actually runs. I am not sure why?

Erase that file.

My guess is that it was created when something was run as root and now
you can’t write to it as a normal user.

Cheers,

Sylvain