Updating README with examples and sample output

Author: pavanky

README.md

@@ -1,2 +1,137 @@
-# arrayfire_python
-Python bindings for ArrayFire
+# ArrayFire Python Bindings
+
+[ArrayFire](https://github.com/arrayfire/arrayfire) is a high performance library for parallel computing wih an easy-to-use API. This project provides Python bindings for the ArrayFire library. It enables the users to write scientific computing code that is portable across CUDA, OpenCL and CPU devices.
+
+## Example
+
+```
+import arrayfire as af
+
+# Display backend information
+af.info()
+
+# Generate a uniform random array with a size of 5 elements
+a = af.randu(5, 1)
+
+# Get the minimum value of a
+a_min = af.min(a)
+
+# Print a and its minimum value
+af.print_array(a)
+af.print_array(a_min)
+```
+
+## Sample outputs
+
+On an AMD GPU:
+
+```
+Using opencl backend
+ArrayFire v3.0.1 (OpenCL, 64-bit Linux, build 17db1c9)
+[0] AMD     : Spectre
+-1- AMD     : AMD A10-7850K Radeon R7, 12 Compute Cores 4C+8G
+
+[5 1 1 1]
+0.4107
+0.8224
+0.9518
+0.1794
+0.4198
+
+
+Min value of a
+[1 1 1 1]
+0.1794
+```
+
+On an NVIDIA GPU:
+
+```
+Using cuda backend
+ArrayFire v3.0.0 (CUDA, 64-bit Linux, build 86426db)
+Platform: CUDA Toolkit 7, Driver: 346.46
+[0] Tesla K40c, 12288 MB, CUDA Compute 3.5
+-1- GeForce GTX 750, 1024 MB, CUDA Compute 5.0
+
+Generate a random matrix a:
+[5 1 1 1]
+0.7402
+0.9210
+0.0390
+0.9690
+0.9251
+
+
+Min value of a
+[1 1 1 1]
+0.0390
+
+Max value of a
+[1 1 1 1]
+0.9690
+```
+
+Fallback to CPU when CUDA and OpenCL are not availabe:
+
+```
+Using cpu backend
+ArrayFire v3.0.0 (CPU, 64-bit Linux, build 86426db)
+
+Generate a random matrix a:
+[5 1 1 1]
+0.0000
+0.1315
+0.7556
+0.4587
+0.5328
+
+
+Min value of a
+[1 1 1 1]
+0.0000
+
+Max value of a
+[1 1 1 1]
+```
+
+The backend selection is automated currently. Choosing a particular backend will be made available in the future.
+
+## Requirements
+
+Currently, this project is tested only on Linux and OSX. You also need to have the ArrayFire C/C++ library installed on your machine. You can get it from the following sources.
+
+- [Download and install binaries](https://arrayfire.com/download)
+- [Build and install from source](https://github.com/arrayfire/arrayfire)
+
+Please check the following links for dependencies.
+
+- [Linux dependencies](http://www.arrayfire.com/docs/using_on_linux.htm)
+- [OSX dependencies](http://www.arrayfire.com/docs/using_on_osx.htm)
+
+## Getting started
+
+If you have not installed the ArrayFire library in your system paths, please make sure the following environment variables are exported.
+
+**On Linux**
+
+```
+export LD_LIBRARY_PATH=/path/to/arrayfire/lib:$LD_LIBRARY_PATH
+```
+
+**On OSX**
+
+```
+export DYLD_LIBRARY_PATH=/path/to/arrayfire/lib:$DYLD_LIBRARY_PATH
+```
+
+On both systems, to run the example, you will need to add the python bindings to your `PYTHONPATH`
+
+```
+export PYTHONPATH=/path/to/arrayfire_python/:$PYTHONPATH
+```
+
+You are now good to go!
+
+## Note
+
+This is a work in progress and is not intended for production use.