Added Readme File

Author: Balint Joo

README.md

@@ -1,14 +1,81 @@
-CMakeShell
-==========
+SyCLDslash MiniApp 
+========================
 
-This is a sample C++ project shell you can use for a CMake
-project. It has
+This git repository contains the SyCLDslash
+package. SyCLDslash depends for its testing reference
+implementatins on QDP++. To build this code it is
+recommended to perform a recursive checkout of the 
+repository:
 
-  * Googletest as a submodule in the ``extern`` directory
-  * A library and headers in the ``include`` directory
-  * A generated (configured) header 
-  * A CMakeConfig.cmake.in file to allow you to export targets to other CMake Project
-  * Allow you to build in stall the file
+[`github.com;bjoo/SyCLDslashWorkspace.git`][https://github.com/bjoo/SyCLDslashWorkspace,git]
+
+which contains QDP++ and its dependencies
+
+In addition `SyCLDslash` depends on `googletest`
+and includes it as a sub-module.
+
+Checking out this repository
+============================
+
+It is highly recommended that this library be checked out using
+the `--recursive` option to Git so that the `googletest` submodule
+is checked out. Alternatively consider checking out [`SyCLDslashWorkspace`][https://github.com/bjoo/SyCLDslashWorkspace,git].
+
+
+
+Building 
+========
+
+This code builds with CMake. 
+
+Useful CMake options are:
+* `-DQDPXX_DIR=<qdp-install-location>/share` - points to the `share` directory of an installation of QDP++ which contains a `FindQDPXX.cmake` file.
+
+* `-DMG_FORTRANLIKE_COMPLEX=ON` enables (RIRIRIRI) storage for complex numbers in 
+vectors. Turning it to 'OFF' 
+
+*  `-DMG_USE_NEIGHBOR_TABLE=OFF` (if set to 'ON` would use a neighbour table taht is actualy a lookup 
+ table. Currently this is set to OFF as that option is not currently supported, neighbor indices are
+explicitly computed.
+
+* `-DMG_USE_LAYOUT_LEFT=OFF` ( if set to `ON` selects left index fastest indexing for View objects, if 
+  set to `OFF` uses right fastest indexing, following Kokkos. )
+
+
+Running The Mini-App:
+=====================
+
+Once building is complete the executables will be in `build/build_sycl_dslash/tests`
+Two executables are of primary interest: `test_dslash_sycl` and `test_dslash_sycl_vperf`.
+
+The `test_dslash_sycl` app performs some unit testing of the dslash operator for a selection
+of vector lenghts.
+
+The performance test is `test_dslash_sycl_vperf` which will first apply a dslash for the 
+purposes of JIT-compiling all the components, and then it will apply dslash again to time
+a single application. It will use this timing to choose a number of iterations commensurate
+to 5 seconds of runtime or minimally 1 iteration if it takes longer than 5 seconds. It will
+then perform 5 timing loops. 
+
+Known issues
+=============
+ - The code has been tested only with the Intel LLVM/SyCL compiler which is in development,
+on a system running an OpenCL runtime. It occasionally crashes OpenCL with the error message:
+
+```OpenCL API failed. OpenCL API returns: -34 (CL_INVALID_CONTEXT)```
+
+This issue needs to be chased down still.
+
+To Do Items
+===========
+
+* Need to figure out how to run this code with other SyCL Compilers e.g. CodePlay etc
+
+Licensing and copyright
+=======================
+
+The Jefferson Lab License under which this workspace is distributed is in the file `LICENSE`
+Licenses for dependencies are included in their source code and/or in the `LICENSES` directory.
+ 
 
 
-Please feel free to add your own code. Remember to rename the projct etc.