quantum-espresso/TODO

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TODO LIST - 5 Jan 2005
BUGS
- fourfold degenerate phonons (Nicolas Mounet)
- Zr hcp (Nathalie)
NEW DEVELOPMENTS TO MERGE
- porting/optimization for Altix by Martin Hilgeman
- support for FFTW3 (partly working) by Pascal Thibadeau
- porting/optimization for SX6 from CASPUR (hopefully coming)
- META-GGA (when finished/tested)
INSTALLATION/PORTING
- make the installation system itself as portable as possible
so that it can be easily used for other codes
- expand configure to cover as many configurations as possible
- exotic architectures: __FUJITSU, FUJ64, HITACHI, NEC-SX5, ...
- Axel's patches for multi-platform build?
COMMON
- data files: move to new format (XML + directories)
- pseudopotentials: support new format (XML)
- adding/removing/modifying input variables is too complex
- time steps in fs (both in input and in output)
- data files: What is exactly the status of file compatibility
between PW and CP/FPMD?
- fix shift in eigenvalues between CP/FPMD and PW
The eigenvalues should be the same
Total energies for charged systems should also be the same
- merge (standard) diagonalization routines
use parallel diagonalization in CP and PW
- merge spherical harmonics between CP-PW and FPMD
merge integration routines, random number generators
- variable declarations : real(kind=DP) or real(dbl), everywhere
- clean up intrinsic functions mess:
real, dreal, float, dfloat, dble
cmplx, dcmplx
conjg, dconjg
imag, aimag, dimag
plus preprocessing!
- error is in flib/ but requires modules: not a good solution,
things in flib/ should not use modules except maybe kinds
and other very low level modules
- replace calls to level-1 blas copy, scal, axpy, with f90 syntax
- cleanup and merge of routines reading and processing PPs;
merge uspp-related stuff ("small box") of CP into PW
PW
- remove potential mixing, save and start from rho instead of V,
at least for scf calculations. Requires fixing the noncolinear
and electric-field cases. For non-scf calculations: we may
still start from V, but the output file MUST include the scf rho,
not a bogus rho as it may happen now
- save rho and/or V in G-space instead of R-space
check that what is read makes sense
- add possibility to read atomic positions from file
- Use more standard choices for crystal axis
- fix problem with j'_l(x)Y_lm(x) for x -> 0 and l=1
- make hpsi/spsi/newd/addusdens/CG/DIIS faster
- remove complex factor i**l from beta fct and q(r) (preliminary)
- shift structure factor from beta to psi when computing becp (reduce memory)
- use real BLAS routine instead of COMPLEX one in hpsi/spsi
(at least 2 times faster).
- use only half of the G's when computing real integrals (2 times faster)
- seek for CG and DIIS algoritms that only use (H-eS)|psi> and not
the two vector separately ... compute it in one single call. (this way
S|psi> is inexpensive)
- output should be more informative and less confused
the printout with UPF PP is incomplete or misleading (lloc=0)
- write explicitly and unambiguosly the units of output quantities
and also what are exactly the output quantites!
Low priority:
- add traceback in error (error_handler module)
- Put SHMEM stuff into a single module
POSTPROCESSING
- complete postprocessing in Gamma case, and with CP/FPMD data
- stm_wfc_matching not working
- the dynamical matrix written by the phonon code does not contain
the information on lattice basis vectors if ibrav=0.
As a consequence most postprocessing codes will not work
PH, D3, Gamma, Raman
- Bug with 4-dimensional irreps is still there!
- the factors in Raman coefficients are not what they should be
(I think) in order to have the stated units A^4/amu
- finish simplification of phonon dispersion calculation:
move all phonon-specific stuff (symmetry etc) from pw into phonon?
- same input for Gamma and PH; Gamma output compatible with Raman
- once Raman works for sure, remove all Raman-related stuff in Gamma
- better algorithms for electron-phonon
- replace "use pwcom" into more "use" statements
DOCUMENTATION
- examples for some features (notably variab;le cell) still missing
automated testing procedure: how to deal with numerical differences?
- expand and update the manual; add a list of FAQ, or of already
answered questions
- complete the developer's (technical) guide
CP/FPMD:
- extend to CP/FPMD possibility to save wavefunctions either
'distributed' or 'collected' in parallel execution
- CP: check on small box size
- CP: the output is horrible
- Documentation needs serious improvements
- Proposals from Princeton:
* just one name for CP and FPMD
* default set up for molecular calculations
* default cutoff values as well as radii of augmented charge
from pseudopotential files
* default choice for spin restricted and spin unrestricted configurations
for neutral systems (maybe already there?)
* automatic FFT grids from cutoff
* automatic box grid for USPP from radii of augmented charge
* default values for emass(emass=300), for dt (dt=7), for preconditioning
cutoff (3)
* the code should consider a common error:
dt^2/emass too large does not allow ortho to converge
or cause energy to increase as time step evolve
* Electronic minimization: SD should be discouraged: use damp as default,
introduce an automatic default schedule, something as:
1st step sd followed by 5 steps with with damp= 0.8,
followed by 5 steps with damp=0.5,
followed by 10 steps with damp=0.3,
followed by 10 steps with damp=0.2,
followed by as many steps as necessary
to achieve the required convergence with damp=0.1
A max number of steps should be included to ensure program termination
The other option allowed should be conjugate gradients:
see Nicola - eventually it could become the default
* Ionic minimization: again SD should be discouraged
A default scheme for simultaneous damped dynamics should be given
(to be tested) for example: zero damp on ions and start with damp=0.5
on electrons to become then 0.1 or perhaps the values should be set
given the forces on the ions
When moving ions and electrons simultaneously an important parameter
is the ratio between electron and ion masses - For minimization it
is better to set up all the ion masses equal - A default value for
the ion masses (considering the defaults for emass and dt) is perhaps
10 AMU (we should do some test to see if 20 AMU is s a safer value)
* Default values for randomization should be given
amprp=0.1 is a decent value - amprp=0.01 is too small
* Car-Parrinello dynamics: the proper masses for the ions, an optimal value
for emass and dt should be set up by the code, based on the smaller atomic
mass and the default value used in the minimizationi
e.g. Amass_default=10 AMU. If the minimum physical AMASS is 20 then
dt=sqrt(2) dt_default and emass should be increased so to keep
emass^2/dt constant
* defaults for the Nose thermostat, introduction of Nose' chains