ModuleNotFoundError: Difference between revisions

Latest revision as of 19:42, 23 April 2022

When you start gnuradio-companion or execute grcc, if the system isn't configured properly for GRC to find the GNU Radio Python scripts and/or libraries, then you will see an error message similar to this one:

If you get this error message and you're running Linux, try the instructions on this page to see if any of them fix the issue. For issues and settings for OSX, see the MacInstall guide.

A. Determine the GNU Radio install prefix

If you don't know or remember your installation prefix, perform the following step:

on a terminal screen, enter gnuradio-config-info --prefix

then use that prefix in place of {your-prefix} in the following commands.

B. Finding the Python library

Using a terminal, enter the following command, substituting the prefix you found above in place of {your-prefix}:

find {your-prefix} -name gnuradio | grep "packages"

Put the appropriate paths it found into the export commands below. Note that the paths are separated by colons :

C. Setting PYTHONPATH

- For almost all Debian / Ubuntu (and derivative) systems, and most other 32-bit Unix/Linux systems, the paths will look like this:

export PYTHONPATH={your-prefix}/lib/{Py-version}/dist-packages:{your-prefix}/lib/{Py-version}/site-packages:$PYTHONPATH

- For other 64-bit systems, the paths will look like this:

export PYTHONPATH={your-prefix}/lib64/{Py-version}/site-packages:$PYTHONPATH

D. Setting LD_LIBRARY_PATH

- For almost all Debian / Ubuntu (and derivative) systems, and most other 32-bit Unix/Linux systems, use:

export LD_LIBRARY_PATH={your-prefix}/lib:$LD_LIBRARY_PATH

- For other 64-bit systems, use:

export LD_LIBRARY_PATH={your-prefix}/lib64:$LD_LIBRARY_PATH

E. Store the commands in a Bash start-up file

Once you have determined the correct two export commands to use, open your text editor and put them in your ~/.bash_aliases or ~/.bashrc or ~/.profile file. Save the file. There are three ways for these changes to take effect.
1. On your terminal enter exit. Then start a new terminal.
2. Type source NAME_OF_FILE_EDITED (e.g. source ~/.profile ).
3. Reboot your computer.

As an example, your entries might be:

export PYTHONPATH=/usr/local/lib/python3/dist-packages:/usr/local/lib/python3.6/dist-packages:$PYTHONPATH
export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH

F. Starting GNU Radio from GUI

If you get the ModuleNotFoundError error while starting GNU Radio from GUI, but can start GNU Radio using the terminal, it is because the environment variables are set for the terminal, but not for your graphical environment. Try one of the listed solutions below.

1. Store the export commands stated in Part E in ~/.profile. Log out and back in for the changes to take effect.
2. Store the export commands stated in Part E in a new shell script (with any name of your choice) in /etc/profile.d/. Restart your computer thereafter.

@@ Line 1: / Line 1: @@
-When you start gnuradio-companion or execute grcc, if you get this, or a similar, error message:
+__NOTOC__
+When you start gnuradio-companion or execute grcc, if the system isn't configured properly for GRC to find the GNU Radio Python scripts and/or libraries, then you will see an error message similar to this one:
+<br><br>
 [[File:ModNotFound.png|300px]]
+<br><br>
-then put the following 'export' commands in your <code>~/.bashrc</code> or <code>~/.profile</code> or <code>~/.bash_aliases</code> file and restart your terminal.<br>
+If you get this error message and you're running Linux, try the instructions on this page to see if any of them fix the issue. For issues and settings for OSX, see the [https://wiki.gnuradio.org/index.php/MacInstall#Typical_Errors_and_Warnings MacInstall guide].
-= Determine your installation prefix =
+== A. Determine the GNU Radio install prefix ==
 If you don't know or remember your installation prefix, perform the following step:
 *   on a terminal screen, enter <code>gnuradio-config-info --prefix</code>
-then use that prefix in place of <code>{prefix}</code> in the following commands
+then use that prefix <b>in place of</b> <code>{your-prefix}</code> in the following commands.
-= Setting PYTHONPATH =
+== B. Finding the Python library ==
-== Linux-based systems and MacOSX / macOS ==
+Using a terminal, enter the following command, substituting the prefix you found above <b>in place of</b> <code>{your-prefix}</code>:
--   For MacOSX / macOS, most Debian / Ubuntu (and derivative) systems, and most other 32-bit Unix/Linux systems, use:
 <pre>
-export PYTHONPATH={prefix}/lib/python3/dist-packages:{prefix}/lib/python3/site-packages:$PYTHONPATH
+find {your-prefix} -name gnuradio | grep "packages"
 </pre>
+Put the appropriate paths it found into the export commands below. Note that the paths are separated by colons <code>: </code>
+== C. Setting PYTHONPATH ==
--   For other 64-bit systems, use:
+-   For almost all Debian / Ubuntu (and derivative) systems, and most other 32-bit Unix/Linux systems, the paths will look like this:
+<pre>
+export PYTHONPATH={your-prefix}/lib/{Py-version}/dist-packages:{your-prefix}/lib/{Py-version}/site-packages:$PYTHONPATH
+</pre>
+-   For other 64-bit systems, the paths will look like this:
 <pre>
-export PYTHONPATH={prefix}/lib64/python3/site-packages:$PYTHONPATH
+export PYTHONPATH={your-prefix}/lib64/{Py-version}/site-packages:$PYTHONPATH
 </pre>
-= Setting LD_LIBRARY_PATH =
+== D. Setting LD_LIBRARY_PATH ==
-== Linux-based systems ==
+-   For almost all Debian / Ubuntu (and derivative) systems, and most other 32-bit Unix/Linux systems, use:
--   For most 32-bit systems and most Debian / Ubuntu (and derivative) systems, use:
 <pre>
-export LD_LIBRARY_PATH={prefix}/lib:$LD_LIBRARY_PATH
+export LD_LIBRARY_PATH={your-prefix}/lib:$LD_LIBRARY_PATH
 </pre>
 -   For other 64-bit systems, use:
 <pre>
-export LD_LIBRARY_PATH={prefix}/lib64:$LD_LIBRARY_PATH
+export LD_LIBRARY_PATH={your-prefix}/lib64:$LD_LIBRARY_PATH
 </pre>
-== MacOSX / macOS ==
+== E. Store the commands in a Bash start-up file ==
-On MacOSX / macOS, the library search path is set primarily by the environment variable DYLD_LIBRARY_PATH. Because of the way the OSX dynamic library loader works, this variable works differently than on Linux. Its primary purpose is in finding libraries in a local path, such as when testing software before installing it, or inside an application. <b>We strongly recommend against setting this variable globally.</b>
+Once you have determined the correct two export commands to use, open your text editor and put them in your <code>~/.bash_aliases</code> or <code>~/.bashrc</code> or <code>~/.profile</code> file. Save the file. There are three ways for these changes to take effect.<br>
+. On your terminal enter <code>exit</code>. Then start a new terminal.<br>
+. Type <code>source NAME_OF_FILE_EDITED</code> (e.g. <code>source ~/.profile</code> ).<br>
+. Reboot your computer.<br>
+As an example, your entries might be:
+<pre>
+export PYTHONPATH=/usr/local/lib/python3/dist-packages:/usr/local/lib/python3.6/dist-packages:$PYTHONPATH
+export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH
+</pre>
+== F. Starting GNU Radio from GUI ==
+If you get the ModuleNotFoundError error while starting GNU Radio from GUI, but can start GNU Radio using the terminal, it is because the environment variables are set for the terminal, but not for your graphical environment. Try one of the listed solutions below.
+. Store the export commands stated in Part E in <code>~/.profile</code>. Log out and back in for the changes to take effect.<br>
+. Store the export commands stated in Part E in a new shell script (with any name of your choice) in <code>/etc/profile.d/</code>. Restart your computer thereafter.<br>