Changing readme to markdown and updating.

Author: nmoran

README

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+# Diagonalisation of Quantum Observables (DoQO)
+
+DoQO is a code for diagonalising obervables for quantum lattice models. It is
+written in C/C++ and makes use of the SLEPc and PETSc libraries to run on
+massively parallel distributed memory cluster. The code has been published along
+with an accompanying paper in the journal of computer physics communications at
+[http://www.sciencedirect.com/science/article/pii/S0010465511000099](http://www.sciencedirect.com/science/article/pii/S0010465511000099).
+
+## To build DoQO. 
+
+1. Ensure petsc and slepc are installed.
+
+2. Create build folder. 
+```
+mkdir build
+```
+
+3. Run cmake to create makefiles. Specify boost location if not found automatically.
+```
+cd build
+cmake ../
+```
+or 
+```
+cmake ../ -DBOOST_ROOT=<boost_path>
+```
+One can also specify an install prefix by setting the CMAKE_INSTALL_PREFIX variable with `-DCMAKE_INSTALL_PREFIX=<path>`
+
+Not if one gets an error about "unset" from FindBoost, this is a cache issue, delete the build directory and start again.
+
+4. Once cmake completes successfully build using.
+```
+make
+```
+
+5. Install binaries using
+```
+make install
+```
+