Dear kwant developers, I got the following error message when installing kwant. Anton already helped me, but told me to send these error messages. *bas@bas-HP-EliteBook-8530w:~$ sudo pip install kwant* *Downloading/unpacking kwant* * Downloading kwant-1.0.0.tar.gz (803kB): 803kB downloaded* * Running setup.py (path:/tmp/pip_build_root/kwant/setup.py) egg_info for package kwant* * Traceback (most recent call last):* * File "<string>", line 17, in <module>* * File "/tmp/pip_build_root/kwant/setup.py", line 39, in <module>* * int(n) for n in Cython.__version__.split('-')[0].split('.'))* * File "/tmp/pip_build_root/kwant/setup.py", line 39, in <genexpr>* * int(n) for n in Cython.__version__.split('-')[0].split('.'))* * ValueError: invalid literal for int() with base 10: '1post0'* * Complete output from command python setup.py egg_info:* * Traceback (most recent call last):* * File "<string>", line 17, in <module>* * File "/tmp/pip_build_root/kwant/setup.py", line 39, in <module>* * int(n) for n in Cython.__version__.split('-')[0].split('.'))* * File "/tmp/pip_build_root/kwant/setup.py", line 39, in <genexpr>* * int(n) for n in Cython.__version__.split('-')[0].split('.'))* *ValueError: invalid literal for int() with base 10: '1post0'* *----------------------------------------* *Cleaning up...* *Command python setup.py egg_info failed with error code 1 in /tmp/pip_build_root/kwant* *Storing debug log for failure in /home/bas/.pip/pip.log* I used *In [3]: cython.__version__* *Out[3]: '0.20.1post0'* Reinstalling cython gave me the following error after successfully installing kwant trough pip. Upon running kwant.test() It gave me the following error: *...........................................................................................E.... ====================================================================== ERROR: kwant.tests.test_plotter.test_plot ---------------------------------------------------------------------- Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/nose/case.py", line 197, in runTest self.test(*self.arg) File "/usr/local/lib/python2.7/dist-packages/kwant/tests/test_plotter.py", line 102, in test_plot fig = plot(sys, site_color=color, cmap='binary', file=out) File "/usr/local/lib/python2.7/dist-packages/kwant/plotter.py", line 1361, in plot return output_fig(fig, file=file, show=show) File "/usr/local/lib/python2.7/dist-packages/kwant/plotter.py", line 663, in output_fig canvas.print_figure(file, *savefile_opts[0], **savefile_opts[1]) File "/usr/local/lib/python2.7/dist-packages/matplotlib/backend_bases.py", line 2192, in print_figure **kwargs) File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_agg.py", line 513, in print_png FigureCanvasAgg.draw(self) File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_agg.py", line 461, in draw self.figure.draw(self.renderer) File "/usr/local/lib/python2.7/dist-packages/matplotlib/artist.py", line 59, in draw_wrapper draw(artist, renderer, *args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/matplotlib/figure.py", line 1079, in draw func(*args) File "/usr/local/lib/python2.7/dist-packages/matplotlib/artist.py", line 59, in draw_wrapper draw(artist, renderer, *args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/matplotlib/axes/_base.py", line 2075, in draw a.draw(renderer) File "/usr/local/lib/python2.7/dist-packages/kwant/plotter.py", line 117, in draw return collections.Collection.draw(self, renderer) File "/usr/local/lib/python2.7/dist-packages/matplotlib/artist.py", line 59, in draw_wrapper draw(artist, renderer, *args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/matplotlib/collections.py", line 301, in draw self._offset_position) File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_agg.py", line 119, in draw_path_collection return self._renderer.draw_path_collection(*kl, **kw) ValueError: Transforms must be a Nx3x3 numpy array ---------------------------------------------------------------------- Ran 96 tests in 13.670s FAILED (errors=1)* I use: matplotlib.__version__ u'1.4.x' Cheers, Bas