mirror of https://gitlab.com/QEF/q-e.git
173 lines
6.9 KiB
Plaintext
173 lines
6.9 KiB
Plaintext
TODO LIST - February 2009
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DEVELOPMENT
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- start move to qe-forge
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COMMON
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- There is some confusion in the various initialization steps:
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- default values at startup
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- reading of the input data and copy into internal variables
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- reading from data file
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- initialization of general variables (that presumably will
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be written to or read from file)
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- initialization of variables used in a specific calculation
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(that may not be written to or read from the data file)
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All these steps are intermixed and/or replicated and it is
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never clear what is initialized where. Same for variable
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allocation.
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- things that should be merged between PW and CP:
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- "cell_base_init" from CP to PW
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- "cellmd" module of PW and "cell_base" of CPV
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- PW "real-space" approach into CP "small boxes"
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- there should be a single function or routine for periodic boundary
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conditions (i.e. bringing all atoms inside the unit cell)
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- spherical harmonics and integration routines
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- use qexml for xml file processing so that a single, easily
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exportable routine, is used everywhere. Requires some though
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on how to deal with parallelism without filling qexml with
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parallel stuff
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- pseudopotentials: add default cutoff values as well as radii
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of augmented charge in pseudopotential files
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- no need for most pseudopotentials used by examples and tests
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to be in the CVS repository
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- adding/removing/modifying input variables is too complex
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Why are some checks on input variables performed in read_namelist,
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while others apparently similar are in */input.f90?
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- time steps in ps/fs (both in input and in output)
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- spherical bessel functions: only one function calculating dj_l/dx
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j_l with l=-1 should not be needed
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- too many confusing error messages are still around
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PW
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- inversion symmetry should allow real hamiltonian and wavefunctions (Dario)
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- nscf calculations are slow. There must be a way to make a better usage
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of the available information from the scf calculation: wavefunctions
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are just discarded. Same for phonon calculation: it shouldn't be needed
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to recalculate everything almost from scratch at each different q-points
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- Fermi-Dirac: pass T instead of "broadening", make it possible
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to use it on top of smearing for free-energy calculations
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- make hpsi/spsi/CG faster
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- remove complex factor i**l from beta fct and q(r)
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- shift structure factor from beta to psi when computing becp (reduce memory)
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- use real BLAS routine instead of COMPLEX one in hpsi/spsi
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(at least 2 times faster).
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- use only half of the G's when computing real integrals (2 times faster)
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- seek for CG and DIIS algoritms that only use (H-eS)|psi> and not
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the two vector separately ... compute it in one single call. (this way
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S|psi> is inexpensive)
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- output should be more informative and less confused
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- write explicitly and unambiguosly the units of output quantities
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and also what are exactly the output quantites!
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- add traceback in error (error_handler module)
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POSTPROCESSING
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- complete postprocessing in Gamma case (only average missing),
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and with CP/FPMD data (in the latter case: when the data file does
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not contain the charge/potential, issue an error message saying
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what is missing and why instead of just crashing in iotk)
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- stm_wfc_matching not working
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- Move to a xml-based format for the dynamical matrix files
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- pwtools: add example of a plot of phonon dispersions
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Fix fqha.f90
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PH, D3, Gamma
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- grid-ization/parallelization of the phonon code: irreps and q-vectors
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should be distributed across procesors/grid computers
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- replace static npertx with dynamical npert
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- C(R) might be calculated at the end of a dispersion run
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- any possibility to merge the various solve_* ?
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- use charge mixing instead of potential mixing
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- clean up the logic of symmetry: there shouldn't be any longer the
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present confusion on whose symmetries we are dealing with. We should
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either keep unchanged the crystal symmetries and use indices to
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locate symmetries of the small group of q, or keep different copies
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for the symmetries of the crystal and of the small group of q
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- same input for Gamma and PH
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- replace "use pwcom" into more "use" statements
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- stop with 'prefix.EXIT' and restart (PH now has it; D3 & Gamma do not
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have any infrastructure for stopping like this)
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- the calculation of P_c x|\psi> should be cleanup up and extracted
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from phonon, since it may be used for other calculations as well
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(TDDFT, photoemission cross sections, etc)
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- spin-polarized BLYP not implemented
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DOCUMENTATION
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- nothing specific right now, but still a lot of work to be done
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CP/FPMD:
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- Proposals from Princeton:
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* default set up for molecular calculations
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* default choice for spin restricted and spin unrestricted configurations
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for neutral systems (maybe already there?)
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* default values for emass(emass=300), for dt (dt=7), for preconditioning
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cutoff (3)
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* the code should consider a common error:
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dt^2/emass too large does not allow ortho to converge
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or cause energy to increase as time step evolve
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* automatic box grid for USPP from radii of augmented charge
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* Electronic minimization: SD should be discouraged: use damp as default,
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introduce an automatic default schedule, something as:
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1st step sd followed by 5 steps with with damp= 0.8,
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followed by 5 steps with damp=0.5,
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followed by 10 steps with damp=0.3,
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followed by 10 steps with damp=0.2,
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followed by as many steps as necessary
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to achieve the required convergence with damp=0.1
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A max number of steps should be included to ensure program termination
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The other option allowed should be conjugate gradients:
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see Nicola - eventually it could become the default
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* Ionic minimization: again SD should be discouraged
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A default scheme for simultaneous damped dynamics should be given
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(to be tested) for example: zero damp on ions and start with damp=0.5
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on electrons to become then 0.1 or perhaps the values should be set
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given the forces on the ions
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When moving ions and electrons simultaneously an important parameter
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is the ratio between electron and ion masses - For minimization it
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is better to set up all the ion masses equal - A default value for
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the ion masses (considering the defaults for emass and dt) is perhaps
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10 AMU (we should do some test to see if 20 AMU is s a safer value)
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* Default values for randomization should be given
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amprp=0.1 is a decent value - amprp=0.01 is too small
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* Car-Parrinello dynamics: the proper masses for the ions, an optimal value
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for emass and dt should be set up by the code, based on the smaller atomic
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mass and the default value used in the minimizationi
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e.g. Amass_default=10 AMU. If the minimum physical AMASS is 20 then
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dt=sqrt(2) dt_default and emass should be increased so to keep
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emass^2/dt constant
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* defaults for the Nose thermostat
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