Merge branch 'parallel_mesh' into master

Author: pancetta

CHANGELOG.rst

@@ -1,5 +1,14 @@
 Changelog
 ---------
+- May 4, 2021: Long time, no see, but this major release 4.0 marks some improvements under the hood:
+
+  - **Rewrote ``mesh`` and ``particle`` data type**: Creation of new arrays for each operation is now avoided by
+    directly subclassing Numpy's ``ndarray``. Somewhat faster, definitively better, less code, future-proof, but also breaking the API. If you use `pySDC`
+    for your project, make sure you adapt to the new data types (or don't upgrade).
+  - **Faster quadrature**: Thanks to `tlunet <https://github.com/tlunet>`_ the computation of the weights is now faster and
+    (even) more reliable. No breaking of any API here...
+
+  This is not much (yet) and if it were not for the API changes, this would have been a minor release.
 
 - August 30, 2019: Version 3.1 adds many more examples like the nonlinear Schrödinger equation, more on Gray-Scott and in particular Allen-Cahn.
   Those are many implemented using the parallel FFT library `mpi4pi-fft <https://bitbucket.org/mpi4py/mpi4py-fft/src/master/>`_, which can now be used with `pySDC`.

pySDC/helpers/plot_helper.py

@@ -39,12 +39,10 @@ def setup_mpl(font_size=8):
         "grid.alpha": 0.25,
         "figure.subplot.hspace": 0.0,
         "savefig.pad_inches": 0.01,
-        "pgf.preamble": [
-            r"\usepackage[utf8x]{inputenc}",  # use utf8 fonts becasue your computer can handle it :)
-            r"\usepackage[T1]{fontenc}",  # plots will be generated using this preamble
-            r"\usepackage{underscore}",
-            r"\usepackage{amsmath,amssymb,marvosym}"
-        ]
+        "pgf.preamble": r"\usepackage[utf8x]{inputenc}"
+                        r"\usepackage[T1]{fontenc}"
+                        r"\usepackage{underscore}"
+                        r"\usepackage{amsmath,amssymb,marvosym}"
     }
     mpl.rcParams.update(pgf_with_latex)
 
@@ -57,9 +55,9 @@ def newfig(textwidth, scale, ratio=0.6180339887):
 
 def savefig(filename, save_pdf=True, save_pgf=True, save_png=True):
     if save_pgf:
-        plt.savefig('{}.pgf'.format(filename), rasterized=True, bbox_inches='tight')
+        plt.savefig('{}.pgf'.format(filename), bbox_inches='tight')
     if save_pdf:
-        plt.savefig('{}.pdf'.format(filename), rasterized=True, bbox_inches='tight')
+        plt.savefig('{}.pdf'.format(filename), bbox_inches='tight')
     if save_png:
-        plt.savefig('{}.png'.format(filename), rasterized=True, bbox_inches='tight')
+        plt.savefig('{}.png'.format(filename), bbox_inches='tight')
     plt.close()

pySDC/helpers/visualization_tools.py

@@ -65,4 +65,4 @@ def show_residual_across_simulation(stats, fname='residuals.png'):
     ax.set_xticklabels(np.arange(maxiter) + 1, minor=False)
     ax.set_yticklabels(np.arange(maxprocs + 1), minor=False)
 
-    plt.savefig(fname, rasterized=True, transparent=True, bbox_inches='tight')
+    plt.savefig(fname,  transparent=True, bbox_inches='tight')