rewording README.md

Author: wkliao

README.md

@@ -1,45 +1,41 @@
-# PnetCDF python
+# PnetCDF for Python
 ![](https://img.shields.io/badge/python-v3.9-blue)
 ![](https://img.shields.io/badge/tests%20passed-49-brightgreen)
 ![](https://readthedocs.org/projects/pnetcdf-python/badge/?version=latest)
 
-PnetCDF-python is a Python interface to
-[PnetCDF](https://parallel-netcdf.github.io/), a high-performance parallel I/O
-library for accessing netCDF files.
-This package allows Python users to access netCDF data using the rich ecosystem
-of Python's scientific computing libraries, making it a valuable tool for
-applications that require parallel access to netCDF files.
+PnetCDF-Python is a Python interface to
+[PnetCDF](https://parallel-netcdf.github.io/), a high-performance I/O library
+for accessing netCDF files in parallel. It can provide MPI-based parallel
+python programs to achieve a scalable I/O performance.
 
 ### Software Dependencies
-* Python 3.9 or above
-* MPI libraries
+* Python 3.9 or later.
+* [numpy](http://www.numpy.org/) Python package.
+* MPI C library and Python package, [mpi4py](https://mpi4py.readthedocs.io/en/stable/install.html).
 * PnetCDF [C library](https://github.com/Parallel-netCDF/PnetCDF), built with shared libraries.
-* Python library [mpi4py](https://mpi4py.readthedocs.io/en/stable/install.html)
-* Python library [numpy](http://www.numpy.org/)
 
 ### Developer Installation
 * Clone this GitHub repository
-* Make sure the above dependent software are installed.
-* In addition, [Cython](http://cython.org/), [packaging](https://pypi.org/project/packaging/), [setuptools>=65](https://pypi.org/project/setuptools/) and [wheel](https://pypi.org/project/wheel/) are required for developer installation.
-* Set the environment variable `PNETCDF_DIR` to PnetCDF's installation path.
-* Make sure utility program `pnetcdf-config` is available in `$PNETCDF_DIR/bin`.
-* Run command below to install.
+* Required software for developer installation:
+  + The above mentioned dependent software are installed and additionally,
+  + [Cython](http://cython.org/), [packaging](https://pypi.org/project/packaging/), [setuptools>=65](https://pypi.org/project/setuptools/) and [wheel](https://pypi.org/project/wheel/).
+* Commands to install.
   ```
-  CC=/path/to/mpicc PNETCDF_DIR=/path/to/pnetcdf/dir pip install --no-build-isolation -e .
+  export CC=/path/to/mpicc
+  export PNETCDF_DIR=/path/to/pnetcdf/dir
+  pip install --no-build-isolation -e .
   ```
-* Testing
-  + Run command `"make check"` to test all the programs available in folders
-    ["test/"](./test) and ["examples/"](./examples) in parallel on 4 MPI
-    processes.
-  + In addition, command `"make ptests"` runs the same tests using 3, 4, and 8
-    MPI processes.
+* Testing -- Command `"make check"` tests all the programs available in folders
+  ["test/"](./test) and ["examples/"](./examples).
 
 ### Additional Resources
+* [Example programs](./examples#pnetcdf-python-examples) are available in
+  folder `./examples`.
 * PnetCDF-python [User Guide](https://pnetcdf-python.readthedocs.io/en/latest)
 * [Data objects](docs/pnetcdf_objects.md) in PnetCDF python programming
 * [Comparison](docs/nc4_vs_pnetcdf.md) of NetCDF4-python and PnetCDF-python
 * [PnetCDF project home page](https://parallel-netcdf.github.io)
-* [PnetCDF repository of C/Fortran library](https://github.com/Parallel-NetCDF/PnetCDF)
+* [PnetCDF of C/Fortran library repository](https://github.com/Parallel-NetCDF/PnetCDF)
 
 ### Developer Team
 * Youjia Li <<youjia@northwestern.edu>>