Re: [Discuss-gnuradio] Python errors running flowgraph - first attempt

[Tom Rondeau]

On Thu, Feb 5, 2015 at 6:26 PM, Chris Hallinan <address@hidden> wrote:

Newbie to gnuradio.  After struggling for a couple weeks with build
issues, I finally have a yocto-based build for an embedded x86_64
target.  I'm trying to execute a flowgraph that I demonstrated
successfully on Ubuntu 14.  I copied the resulting .grc file from
Ubuntu to the x86_64 target.  It is based directly from gnuradio
tutorial, a broadcast FM receiver.

gnuradio-companion runs on my embedded x86_64 target, but issues three
XML parse errors on startup:

Preferences file: /home/root/.grc
Block paths:
   /usr/share/gnuradio/grc/blocks
   /usr/local/share/gnuradio/grc/blocks
   /home/root/.grc_gnuradio

XML parser: Found 3 erroneous XML files while loading the block tree

Displaying these errors from Help shows all three are similar with the
text "Element <block|param>...does not follow DTD, expecting..."

Then gnuradio-companion starts up and displays my flowgraph.

When I try to 'Run' it, I get:

Showing: "/home/root/gr-tutorial-broadcast-fm-rx.grc"
Generating: "/home/root/my_gui.py"
Executing: "/home/root/my_gui.py"

Traceback (most recent call last):
  File "/home/root/my_gui.py", line 8, in <module>
    from PyQt4 import Qt
  File "/usr/lib/python2.7/site-packages/PyQt4/Qt.py", line 1
    from PyQt4.QtCore import *\n

Looking at Qt.py, it contained 8 lines that looked like this:
from PyQt4.QtCore import *\n
... <repeated 7 more times with various modules>
SyntaxError: unexpected character after line continuation character

Once I "hacked" the '\n' from these lines, and reran the flowgraph

Hi Chris,

That looks like maybe it's a problem between code editors adding or misinterpreting the line end character.

In general, though, we don't recommend people actually run GRC on their embedded devices. You want to build and debug everything on a host. If using Python, you just copy over the resulting Python file to the device you want to run on. If it's a C++ project, you'd cross-compile and then move the binary over. That would help with these issues, I think. 

 

using 'Run', now I get this:

Traceback (most recent call last):
  File "/home/root/my_gui.py", line 8, in <module>
    from PyQt4 import Qt
  File "/usr/lib/python2.7/site-packages/PyQt4/Qt.py", line 2, in <module>
    from PyQt4.QtDeclarative import *

ImportError: /usr/lib/python2.7/site-packages/PyQt4/QtDeclarative.so:
undefined symbol: _ZTI16QDeclarativeView

This looks like some type of package mismatch? I'm not a python guy :(

Yes, looks like a version mismatch. Possibly between PyQT and QT or something to do with QWT.

 

My yocto-based build configuration looks like this:
meta-sdr: master
meta-python: dizzy
meta-oe: dizzy
oe-core: dizzy

Any advice is appreciated on how to resolve this.

Regards,

Chris Hallinan

I'll have to let Philip Balister comment on this. But using dizzy and meta-sdr's master could be part of the problem. I've mostly stayed on daisy for the OE stuff, so I don't have any knowledge of the version issues here. Though it's probably time I move up to dizzy.

Tom