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MEEP FDTD libEGL warning: DRI2: failed to authenticate

I have a fresh install of MEEP (the FDTD package) in a Conda environment, on a fresh install of elementaryOS. I'm attempting to run the "Visualizing 3D Structures" example code found here. I've installed both both pymeep and pymeep-extras, as well as scikit-image and vispy (dependencies for the example code).
Running python3 visualizing_3d_structures.py within the Conda environment yields the error libEGL warning: DRI2: failed to authenticate, and no graphical display appears. A simple Google search reveals a number of StackExchange posts (with various, at times contradictory advice) relating to a similar issue specific to Raspbian. none of which seems relevant here, unfortunately.

This could happen if there isn't a backend (software graphic device) installed in the environment, but there is a libEGL installed at the system-level (EGL is one of the backends for which MEEP will search).
The recommended backend for MEEP is PyQt, so installing that should be sufficient get it working:
conda install -c conda-forge pyqt
That works for me. However, the tutorial directly recommends mayavi. This will also install pyqt, but obviously has extra stuff as well. So, if you want to strictly follow the tutorial, then run
conda install -c conda-forge mayavi
I verified that also gets it working.

No module found error for a downloaded package (sksparse.cholmod) and how to download a package from the internet to conda

I need to use the sksparse.chomod package however my pycharm does not let me install it as it can't seem to find it.
I found the sksparse package on github and downloaded it but I do not know how to add a package downloaded from the internet into a conda environment. So, my first question would be can you download a package from github and add it to your conda environment, and how do you do this?
As I did not know how to do the above I instead saved the package within my project and thought I could simply import sksparse.cholmod. However, the line in my code that says import sksparse.cholmod as sks has no errors with it, so I assumed that meant this was ok, but when I try to run my file I get this error:
import sksparse.cholmod as sks
ModuleNotFoundError: No module named 'sksparse.cholmod'
If I have downloaded the package into my project why can't it be found, yet there are no errors when importing?
The cholmod file is a pyx file which I've been told should not be a problem.
Please could anyone help, I am reasonably new to python and I am looking for a straight forward solution that won't be time consuming.

It was an issue with windows, I was able to fix this using the instructions on this link
https://github.com/EmJay276/scikit-sparse
We must follow these steps precisely:
(This was tested with a Anaconda 3 installation and Python 3.7)
Install these requirements in order:
'''
conda install -c conda-forge numpy - tested with v1.19.1
conda install -c anaconda scipy - tested with v1.5.0
conda install -c conda-forge cython - tested with v0.29.21
conda install -c conda-forge suitesparse - tested with v5.4.0
'''
Download Microsoft Build Tools for C++ from https://visualstudio.microsoft.com/de/visual-cpp-build-tools/ (tested with 2019, should work with 2015 or newer)
Install Visual Studio Build Tools
Choose Workloads
Check "C++ Buildtools"
Keep standard settings
Run ''' pip install git+https://github.com/EmJay276/scikit-sparse '''
Test ''' from sksparse.cholmod import cholesky '''
Use all the versions stated for numpy etc, however with scipy I installed the latest version and it worked fine.

Can't find Brew installed packages on Mac M1 in Pycharm

I'm having trouble installing packages and using them in Pycharm. I've followed various threads (I'm new to Macs and seem to have tried everything) now I'm stuck.
In this case, I want to use the package xgboost.
I have brew installed, after launching a terminal using Rosetta:
%brew install xgboost
Warning: xgboost 1.3.3 is already installed and up-to-date.
It appears installed OK here:
/opt/homebrew/Cellar/xgboost
I also have Python installed here:
/opt/homebrew/Cellar/python#3.9
But no matter how I configure an Interpreter in Pycharm, I can't seem to get the package recognised.
Where have I gone wrong?

I am very unsure exactly how, but I've got this working.
Following: https://abbasegbeyemi.me/blog/homebrew-python-apple-m1
I changed the order of elements in my path:
export PATH=/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/homebrew/bin
then a new interpreter in Pycharm using:
usr/local/Cellar/Python#3.9/3.9.2_2/bin/python3.9
Now I can install packages just using pip in pycharm and it works.
This has been 6 hours of pain - warning to anyone who isn't well versed in macs, setting up an M1 for python dev was a complete nightmare for me.

Docs: https://xgboost.readthedocs.io/en/latest/build.html
Pre-built binary wheel for Python
If you are planning to use Python, consider installing XGBoost from a pre-built binary wheel, available from Python Package Index (PyPI). You may download and install it by running
# Ensure that you are downloading one of the following:
# * xgboost-{version}-py2.py3-none-manylinux1_x86_64.whl
# * xgboost-{version}-py2.py3-none-win_amd64.whl
pip3 install xgboost

Installing gdal with conda and setting environmental variables

I have been trying to get the gdal library work using Python 2.7 and Anaconda in Windows 8 environment.
Besides gdal, I have also installed libgdal (frankly, I don't really understand the difference between the two). I now seem to have gdal 2.1.0 and 2.0.2 as well as libgdal 2.1.0.
However, when I run my Py code, there is a gdal error:
'gdalwarp' is not recognized as an internal or external command,
operable program or batch file.
I have already set the GDAL_DATA environmental variable to point to
C:\Anaconda\pkgs\libgdal-2.1.0-vc9_0\Library\share\gdal
I have also added a path, although I am not entirely sure where this should point to:
C:\Anaconda\pkgs\libgdal-2.1.0-vc9_0\Library\bin
I have tried the same with gdal 2.0.2 without success. gdalwarp.exe does seem to exist under libgdal 2.1.0 and gdal 2.0.2.
Any ideas? Is there an issue with the installation or have I not set the environmental variables correctly?
FYI, I have tried various installation commands, notably:
conda install gdal
conda install -c conda-forge gdal
conda install -c anaconda gdal
Addendum: I have found a manual solution: I set the GDAL_DATA and PATH variables in the terminal (pointing to libgdal 2.1.0) before running the code...
However, there is still an issue when I run my Py code: it is supposed to convert a tiff file to shp with gdal_polygonize:
cmd = 'gdal_polygonize.py %s -f "ESRI Shapefile" %s'%(dst_tif, dst_shp)
There is no error but the shapefile is not created (which leads to an error later on in the code). Any ideas as to why gdal is still not working correctly?
I have tried pointing the env variables to osgeo:
set PATH=%PATH%;C:\Anaconda2\Lib\site-packages\osgeo\scripts
set GDAL_DATA=C:\Anaconda2\Lib\site-packages\osgeo\data\gdal
Gdalinfo works but the gdal_polygonize used in my Py code does not appear to work.

The key is the activation script which is (potentially) executed when activating the environment. Not every GDAL build for Conda contains this. In my experience recent Conda-Forge builds are really good.
With your requirements of py27 and GDAL 2.1 i can get it working by following these steps:
1) Create a new environment: conda create -n gdaltest python=2.7
2) Activate: activate gdaltest
3) Install GDAL: conda install gdal=2.1 -c conda-forge
4) Reactivate environment: deactivate + activate gdaltest
This forces the just installed activation script to be executed, this sets the environment variables.
If i start python and run os.system("gdalinfo"), i can see its picked up correctly. And running os.environ['GDAL_DATA'] confirms the path is set correctly.
You can view the (de)activation script yourself at:
C:\Miniconda3\envs\<env name>\etc\conda\activate.d\gdal-activate.bat
A few years ago this didn't work as well as it does today, so make sure you have a recent Conda version (4.3.x) etc.
The benefit of this method is, that when switching environments, your paths are also changed accordingly. A "hard coded" GDAL_DATA path could potentially cause some compatibility issues if you mix and match different GDAL versions (although normally is should work OK).

pyzmq installation error with dependency on gcc

I tried installing pyzmq by http://ipython.org/ipython-doc/dev/install/install.html as I want to install ipython. But it has dependency on pyzmq which has dependency on gcc. I already have gcc installed but still I am getting the following error while install pyzmq.
compilation terminated.
error: Setup script exited with error: command 'gcc' failed with exit status 1
The script also has following in it:
If you expected pyzmq to link against an installed libzmq, please check to make sure:
* You have a C compiler installed
* A development version of Python is installed (including headers)
* A development version of ZMQ >= 2.1.4 is installed (including headers)
* If ZMQ is not in a default location, supply the argument --zmq=<path>
* If you did recently install ZMQ to a default location,
try rebuilding the ld cache with `sudo ldconfig`
or specify zmq's location with `--zmq=/usr/local`
You can skip all this detection/waiting nonsense if you know
you want pyzmq to bundle libzmq as an extension by passing:
`--zmq=bundled`
I will now try to build libzmq as a Python extension
I already have all the above but still issues. I am guessing I have path issues i.e. may be pyzmq is looking at other location but how do I solve this problem

This is a huge issue in Windows to install ipython. I would recommend Windows users to never go the pip or easy_install way to install it. I faced a lot of issues like above. I read that it still has dependencies issues on github i.e. via pip.
I got it installed finally by this:
Download and install Anaconda
Update IPython to the current version by:
Go to Anaconda directory or look for anaconda cmd & do the following:
conda update conda
conda update ipython