Friday, August 13, 2010

Week Aug 9 - 13

On Monday I learned fwrap (excellent piece of software btw), there were a few minor technical issues, that I communicated with Kurt on the fwrap mailinglist and I also send him a simple patch, so that it works fine for my fortran code (functions returning the value itself, instead of a tuple of length 1).

Then I took my old fortran based shooting method solvers that I wrote couple years ago and wrapped them using fwrap and run couple simulations against my FE solver.

On Tuesday we had a lunch with all the advisors and students and the llnl director and a little presentation about what we did.

On Wednesday I run shooting method calculations for 50 states of silver, both for selfconsistent DFT potential and Z/r potential. I then also run the FE solver for the same DFT potential and compared results. There are lots of small technical issues, for example I had to use cubic splines to interpolate the potential, play with the mesh for the shooting method and so on.

However, the shooting method and FE agrees to every single printed digit, after making sure that the mesh is ok for both methods. For all potentials that I tried. That's very cool.

In the process of it, I also wrote a patch to SymPy to calculate exact energies for the Hydrogen atom, both from Schroedinger and Dirac equations. I still need to polish it a bit.

On Thursday I run couple more calculations and setup a poster and had a poster session, it was two hours, and I think around 7 people (not counting other students and people from our group) stopped by and talked with me about it, so I was very happy. Being able to solve radial Schroedinger and especially Dirac equations robustly is something that several people in the lab would really need.

Today I talked little bit (finally) about some Green functions in QM and QFT with a postdoc in the Quantum Simulations group, that I always wanted to, but didn't have time before, then packed my things and went back to Reno.

My plan for the next week(s) is to wrap up what I did and put it into articles. I already have enough material for some articles, so it has to be done. In parallel, I'd like to finish the FE Dirac solver, the coding is done, but now I need to play with adaptivity and also investigate if we are getting the spurious states, that other people are getting when using b-splines.

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