Kinda stuff Professor Shonku never wrote in his diary(to the best of my memory)

Well, I am here to post about failures or at least lack of successes. Shonku's diary posts always reported of instant successes or incessant progresses. But for us, the not-so-gifted folks, success comes slow and late. I have given up on MATLAB coming through with the exact diagonalization programs I was trying out. After couple of weeks I began to suspect that my desktop is hung up. Now, I have bigger fish to fry. The plan has changed. I am to come up with a data structure for defining lattice models in Qutip. I have been busy figuring out the class definitions of Qutip and Quspin. Quspin is a wonderful open source package for calculations on lattice models. I learnt a lot from looking at their codes. It is possible to just load the modules from the two packages individually and make them compatible through their common representation in numpy. However, I would love to initiate Qutip's own efforts on lattice models. It would require a lot of guile to outclass the programs of Quspin which are state-of-the-art both in terms of theoretical tricks and programming soundness.

Exploiting symmetry is no longer a luxury, it is a necessity. Quspin uses all the major symmetry hacks known. But I have not seen any use of permutation symmetry in them yet. But that would come later; first, I have to develop the basic class for the lattice models.



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