quantum-espresso/upflib/TODO_upflib.md

##NOTES##

• Routines or utilities existing in two copies, one for QE and one for upflib:

  • randy in module uspp, file uspp.f90
  • invmat simplified version, in module upf_invmat, file upf_invmat.f90
  • capital, lowercase, isnumeric, matches, version_compare in module upf_utils, file upf_utils.f90
  • errore and infomsg as upf_error, in file upf_error.f90

• Module variables that have been (partially) duplicated:

  • kinds => upf_kinds (only dp)
  • constants => upf_const
  • nsp in ions_base points to nsp in uspp_param

• TO BE DONE:

  • PP files: semilocal Vnl and human-readable sections are not read, but they should: converters may make a good usage of that information How to read from a given record in fortran (without direct I/O) ? fseek, ftell, pos= identifier, stream I/O?

  • set the correct value of nsp in uspp_param when allocate_uspp is called, use it ONLY inside upflib, remove link of nsp in ions_base to uspp_param

  • nh(:) is allocated in init_uspp_dims, but maybe it should allocated together with upf(:), when upf is read? Or maybe nh should be part of upf? It is used in many many places, though!

  • Merge pseudopotential_indexes from CPV/src/pseudopot_sub.f90 with the uspp initialization in upflib (init_us_1 etc); merge qvan2b and qvan2 (requires merge of interpolation tables qrad and qradb)

  • upf_ions now contains just a function n_atom_wfc: move somewhere else?

  • upf_spinorb contains just two variables: merge into uspp? add to it the two functions spinor and sph_ind used only for spin-orbit?

  • lmaxq should be "the maximum value of L in Q functions", not "... + 1" and should be used to dimension arrays where l=0,...,L. The dimension of spherical harmonics (2*lmaxkb+1)^2 is something different and should be stored in a different variable (something like ylmdim, or maxlm)

  • Names of interpolation tables and related routines are random: CP PW new name? contains computed in betagx tab tab_beta beta(G) functions compute_betagx, dbetagx dbeta(G)/dG compute_betagx qradx qrad tab_q Q(G) for USPP/PAW init_tab_qrad dqradx dQ(G)/dG compute_qradx tab_at tab_atwfc atomic R_nl(G) init_tab_atwfc (tab_atrho atomic rho(G) to be done) (tab_vloc local potential to be done)

• upflib restructuring:

  • shall we keep just one src folder ? or structure it a bit more, such as upflib/baselib all basic data structures and io
    upflib/advlib advanced initializations (init_us_0,1,2) upflib/tools tools from upftools