Fixing NetCDF4 documentation now that it is available on conda-forge

Author: mikaem

README.rst

@@ -81,13 +81,7 @@ will not help you with MPI or FFTW.
 
 For IO you need to install either `h5py <https://www.h5py.org>`_ or
 `netCDF4 <http://unidata.github.io/netcdf4-python/>`_ with support for
-MPI. The first one is available from the coda-forge channel through::
+MPI. Both are available from the coda-forge channel through::
 
-    conda install -c conda-forge h5py=*=mpi_mpich_*
+    conda install -c conda-forge h5py=*=mpi* netcdf4=*=mpi*
 
-NetCDF4, on the other hand, is not available with MPI on the conda-forge
-channel. The library is available, though, for both OSX and
-linux from the `spectralDNS <https://anaconda.org/spectralDNS>`_ channel
-on anaconda cloud::
-
-    conda install -c spectralDNS netcdf4-parallel

docs/source/installation.rst

@@ -8,6 +8,7 @@ Mpi4py-fft has a few dependencies
     * `numpy`_
     * `cython`_ (build dependency)
     * `h5py`_ (runtime dependency, optional)
+    * `netCDF4`_ (runtime dependency, optional)
 
 that are mostly straight-forward to install, or already installed in
 most Python environments. The first two are usually most troublesome.
@@ -25,22 +26,16 @@ can be achieved with
 
 ::
 
-    conda create --name mpi4py-fft -c conda-forge mpi4py-fft h5py=*=mpi*
+    conda create --name mpi4py-fft -c conda-forge mpi4py-fft
     conda activate mpi4py-fft
 
 Note that this gives you mpi4py-fft with default settings. This means that
-you will probably get the openmpi backend, and it is also likely that
-conda-forge chooses numpy with the mkl backend. Unfortunately, the mkl
-python package makes adjustments to the FFTW library and hard to resolve
-bugs may arise. For this reason it is advisable to make sure that mkl
-is not installed. This can be achieved with, e.g.,
+you will probably get the openmpi backend. To make a specific choice of 
+backend just specify which, like this
 
 ::
 
-    conda create --name mpi4py-fft -c conda-forge mpi4py-fft mpich nomkl h5py=*=mpi*
-
-Note that the nomkl package makes sure that numpy is installed without
-mkl, whereas mpich here chooses this backend over openmpi.
+    conda create --name mpi4py-fft -c conda-forge mpi4py-fft mpich
 
 If you do not use `conda`_, then you need to make sure that MPI
 and FFTW are installed by some other means. You can then install
@@ -78,23 +73,15 @@ Additional dependencies
 -----------------------
 
 For storing and retrieving data you need either `HDF5`_ or `netCDF4`_, compiled
-with support for MPI. `HDF5`_ is already available
-with parallel support on `conda-forge`_ and, if it was not installed at the same
-time as mpi4py-fft, it can be installed (with the mpich backend for MPI) as
-
-::
-
-    conda install -c conda-forge h5py=*=mpi_mpich_*
-
-A parallel version of `netCDF4`_ cannot be found on the conda-forge channel,
-but a precompiled version has been made available for python 2.7, 3.6 and 3.7
-on the `spectralDNS channel`_, for both osx and linux
+with support for MPI. Both are available
+with parallel support on `conda-forge`_ and can be installed into the 
+current conda environment as
 
 ::
 
-    conda install -c spectralDNS netcdf4-parallel
+    conda install -c conda-forge h5py=*=mpi* netcdf4=*=mpi*
 
-Note that parallel HDF5 and NetCDF4 often are available as modules on
+Note that parallel HDF5 and NetCDF4 often are available as optimized modules on
 supercomputers. Otherwise, see the respective packages for how to install
 with support for MPI.