Errors and Suggestions for the Manual

Elk Users
James Mudd
2013-07-26
2013-07-26
  • James Mudd
    James Mudd
    2013-07-26

    Thought it might be good to have a thread where people can post errors and suggestions for the manual.

    Errors: In the Elk 2 manual it still says you need libxc version 1.x this isn't true (You need libxc 2.x for Elk 2.x) but took me a long time to work out (Its probably fine if you have been following the development reading the change log etc.)

    There is a parameter called hybmix which allows you to select the hybrid mixing it is missing from the manual. I only found this reading examples, despite knowing what I wanted to do. I'm guessing there may be others missing

    Suggestion: Would it be possible to have a section in the manual to describe which tasks to run in which order to use libxc functionals. I'm still confused by this should I be running task 0 then 5 or 0 with LDA then 5 with hybrid?? And should the option hybrid be set true or not? Its not in the Si libxc example. I'm aware this functionality has just been added to Elk so maybe the documentation is coming.

    Its great to have such a nice updated open source DFT code available keep up the good work.

     
  • Markus
    Markus
    2013-07-26

    Hi James,

    for a hybrid functional calculation you just need to run task 0 first and then task 5 with hybrid=true and hybridc=0.25 or so. hybmix has been removed (some examples have not been updated yet). Hybrid functionals are handled through the Hartree-Fock code. However, be aware that the implementation is experimental and I would not trust the results; they do not compare very well with data found in the literature. Further, it is rather slow.

    By the way, note that screened hybrids do not work.

    Markus

     
  • James Mudd
    James Mudd
    2013-07-26

    Hi Markus

    Thanks very much for the reply. That would explain by problem, I was using HSE06 but I cant converge it, but if its not properly supported that's why.

    Is there a list of what is and isn't supported from libxc?

    James