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dftlibs / xcfun

XCFun: A library of exchange-correlation functionals with arbitrary-order derivatives
https://dftlibs.org/xcfun/
Mozilla Public License 2.0
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Implementing a new functional on a basis of Slater exchange #150

Closed alexmir18 closed 3 years ago

alexmir18 commented 3 years ago

Hello, This is not really an issue, but a question. I would like to compute an integral over electron density to some power n for my research. A natural approach would be to start with the Slater exchange functional and modify its prefactor and exponent. I tried to locate a function that evaluates such integral in the xcfun library, but couldn't. If you could advise on how this can be done, I would highly appreciate it. Thanks!

Alex

robertodr commented 3 years ago

Hello! You might want to have a look at these two files https://github.com/dftlibs/xcfun/blob/master/src/functionals/slater.hpp and https://github.com/dftlibs/xcfun/blob/master/src/functionals/slaterx.cpp to get started. Note that there is no concept of integration grid in XCFun itself. What XCFun does is evaluate a functional given densities (gradients of densities, etc.) The integration is supposed to be done outside of XCFun.

bast commented 3 years ago

If you are interested in a relatively lightweight way to generate a numerical integration grid to integrate that density, check out https://github.com/dftlibs/numgrid (I am the developer of the latter, not saying this for self promotion but that I am happy to help with that one if you go for it).

alexmir18 commented 3 years ago

Thanks! I will take a look at slater cpp/hpp files and check out the numerical integration grid. Thank you for the suggestion!