unpin sphinx version

Modify tutorial to remove warnings.

doc/source/conf.py

@@ -226,6 +226,8 @@ latex_documents = [
 
 latex_engine = 'xelatex'
 
+latex_use_xindy = False  # Xindy not installable in CI environment
+
 # The name of an image file (relative to this directory) to place at the top of
 # the title page.
 #latex_logo = None
@@ -245,7 +247,9 @@ latex_domain_indices = False
 autosummary_generate = True
 
 autoclass_content = "both"
-autodoc_default_flags = ['show-inheritance']
+autodoc_default_options = {
+    'show-inheritance': True,
+}
 
 # -- Teach Sphinx to document bound methods like functions ---------------------
 import types

doc/source/tutorial/kpm.rst

@@ -538,9 +538,9 @@ the random vectors.
     (spectrum.energies, spectrum.densities * 8),
     [
         (r'Longitudinal conductivity $\sigma_{xx} / 4$',
-         (energies, cond_array_xx / 4)),
+         (energies, cond_array_xx.real / 4)),
         (r'Hall conductivity $\sigma_{xy}$',
-         (energies, cond_array_xy))],
+         (energies, cond_array_xy.real))],
     )
 
 .. _advanced_topics:

doc/source/tutorial/magnetic_field.rst

@@ -161,7 +161,7 @@ with the Landau levels shown as dashed lines.
     kwant.plotter.bands(syst, ax=ax, params=params)
 
     h = landau_syst.hamiltonian_submatrix(params=params)
-    for ev in scipy.linalg.eigvals(h):
+    for ev in scipy.linalg.eigvalsh(h):
       ax.axhline(ev, linestyle='--')
 
 The dispersion and the Landau levels diverge with increasing energy, because the real space

doc/source/tutorial/plotting.rst

@@ -31,6 +31,9 @@ these options can be used to achieve various very different objectives.
     # --------------------------
     #  - demonstrate different ways of plotting
 
+    import warnings
+    warnings.simplefilter("ignore")
+
     from matplotlib import pyplot
 
     import kwant

docker/kwant-latest.yml

@@ -23,7 +23,7 @@ dependencies:
     - pytest-flakes
     - pytest-pep8
     # Documentation building
-    - sphinx=1.7.4  # later versions seem to have problems
+    - sphinx
     - numpydoc
     - requests
     - pip: