quantum-espresso/Modules/wannier_gw.f90

418 lines
14 KiB
Fortran

!
! Copyright (C) 2004-2007 Quantum ESPRESSO group
! This file is distributed under the terms of the
! GNU General Public License. See the file `License'
! in the root directory of the present distribution,
! or http://www.gnu.org/copyleft/gpl.txt .
!
!
! Modified by Joshua Elliott November 2020 as JDE
!
!--------------------------------------------------------------------------
!
MODULE wannier_gw
!! The variables needed for \(\texttt{gww-gwl}\) code (\(\texttt{head.x}\)).
!
USE kinds, ONLY: DP
!
SAVE
!
!From HEAD
LOGICAL :: l_head=.false.
!! if TRUE calculates the head of the symmetrized dielectric matrix -1
INTEGER :: n_gauss
!! number of frequency steps for head calculation
REAL(kind=DP) :: omega_gauss
!! period for frequency calculation
INTEGER :: grid_type
!! 0 GL -T,T 2 GL 0 T 3 Equally spaced 0 Omega
INTEGER :: nsteps_lanczos
!! number of lanczos steps
!options for grid_freq=5
INTEGER :: second_grid_n
!! sub spacing for second grid
INTEGER :: second_grid_i
!! max regular step using the second grid
LOGICAL :: l_scissor
!! if TRUE displaces occupied manifold of scissor(1) and unoccupied manifold of scissor(2)
REAL(kind=DP) :: scissor(2)
!! l\_scissor
!From pw4gww
TYPE real_matrix_pointer
REAL(kind=DP), DIMENSION(:,:), POINTER :: p
END TYPE real_matrix_pointer
TYPE complex_matrix_pointer
COMPLEX(kind=DP), DIMENSION(:,:), POINTER :: p
END TYPE complex_matrix_pointer
TYPE optimal_options
!! options for obtaining optimal basis sets
LOGICAL :: l_complete
!! if TRUE just do a diagonalization
INTEGER :: idiago
!! kind of optimization: 0=Gram-Schmidt like
INTEGER :: ithres
!! kind of threshold: 0=on modulus square
REAL(kind=DP) :: thres
!! value of threshold
END TYPE optimal_options
REAL(kind=DP), ALLOCATABLE :: wannier_centers(:,:,:)
!! wannier centers in a.u.
REAL(kind=DP), ALLOCATABLE :: wannier_radii(:,:)
!! wannier centers in a.u.
INTEGER, ALLOCATABLE :: w_centers(:,:,:)
!! wanier centers on the grid
INTEGER, ALLOCATABLE :: w_radii(:,:)
!! wannier lengths in grid units
COMPLEX(kind=DP), ALLOCATABLE :: u_trans(:,:,:)
!! unitarian transformation from bloch wfcs to wannier'
INTEGER :: numw_prod
!! number of products \(w_i(r) w_j(r)\) then of orthonormalized products
INTEGER :: num_nbndv(2)
!! number of valence bands
INTEGER :: num_nbnds
!! number of studied bands valence plus a part of conduction's
REAL(kind=DP), ALLOCATABLE :: becp_gw(:,:,:)
!! to store projections of wfcs with us projectors
REAL(kind=DP), ALLOCATABLE :: becp_gw_c(:,:,:)
!! to store projections of wfcs with us projectors for {c'} subspace
COMPLEX(kind=DP), ALLOCATABLE :: expgsave(:,:,:,:)
!! to store exp_igx on us augmentation functions
INTEGER :: nset
!!number of states to be read written from/to file simultaneously
LOGICAL :: l_truncated_coulomb
!! if TRUE the Coulomb potential is truncated
REAL(kind=DP) :: truncation_radius
!! truncation radius for Coulomb potential
INTEGER :: remainder
!! 1-cutoff 2-distance 3-no remainder 4-postprocessing from W 5-postprocessing from dressed polarization P
INTEGER :: restart_gww
!! for restarting the calculation of gww stuff, 0 begins from beginning
LOGICAL :: l_gram
!! if TRUE uses gram schmidt for orthonormalizing the products of wanniers
!LOGICAL :: l_head!if TRUE calculates the head of the symmetrized dielectric matrix -1
!INTEGER :: n_gauss!number of frequency steps for head calculation
!REAL(kind=DP) :: omega_gauss!period for frequency calculation
LOGICAL :: l_exchange
!! if TRUE calculate the exchange terms with k-points sampling
LOGICAL :: l_zero
!! if TRUE calculate also the \(v\) and \(v^{1/2}\) operators with G=0,G'=0 put to 0
LOGICAL :: l_wing
!! if TRUE calculate also the wing terms, it requires the file .e_head
!INTEGER :: grid_type!0 GL -T,T 2 GL 0 T 3 Equally spaced 0 Omega
INTEGER :: nset_overlap
!! number of states to be read written from/to file simultaneously, when
!! calculating overlaps
INTEGER :: nspace
!!space on grid for evalueation of exchange-type integrals
REAL(kind=DP) :: ecutoff_global
!!cut off in Rydbergs for G sum on (dense charge grid)
INTEGER :: maxiter2
!! max number of iteration for the genaralized maximally localized wannier
!! of the second conduction manifold
REAL(kind=DP) :: diago_thr2
!! thresold for electronic states used in c_bands for upper
!! conduction manifold if any, if ==0 used same cutoff as for valence
LOGICAL :: l_plot_mlwf
!! if TRUE save the orthonormal wannier for plotting
INTEGER :: max_ngm
!! max number of g vector for charge grid effctively stored
!variables for parallelization on matrices
LOGICAL :: l_pmatrix
!! if TRUE parallelize on matrices
INTEGER :: p_mpime
!! processor number
INTEGER :: p_nproc
!! number of processors
INTEGER :: npcol
!! number of processor columns
INTEGER :: nprow
!! number of processor rows
INTEGER :: icontxt
!! blacs descriptor
INTEGER :: myrow
!! actual processor row
INTEGER :: mycol
!! actual processor column
LOGICAL :: l_coulomb_analysis
!! if TRUE after polarization analysis consider eigenvalues of coulomb potential
REAL(kind=DP) :: cutoff_coulomb_analysis
!! cutoff for coulomb analysis
INTEGER :: n_pola_lanczos
!! number of orthonormal states for polarization lanczos-style
INTEGER :: n_self_lanczos
!! number of orthonormal states for self-energy lanczos-style
INTEGER :: nsteps_lanczos_pola
!! number of lanczos steps for the polarizability
INTEGER :: nsteps_lanczos_self
!! number of lanczos steps for the self_energy
REAL(kind=DP) :: s_pola_lanczos
!! cutoff for lanczos basis for polarization
REAL(kind=DP) :: s_self_lanczos
!! cutoff for lanczos basis for self-energy
INTEGER :: nump_lanczos
!! dimension of basis for lanczos calculation of the polarization
INTEGER :: nums_lanczos
!! dimension of basis for lanczos calculation of the self-energy
REAL(kind=DP) :: s_g_lanczos
!! cutoff for absolute value of trial green function
LOGICAL :: l_pmat_diago
!! if TRUE find the basis for the polarization diagonalizing the O matrix
REAL(kind=DP) :: pmat_ethr
!! threshold for diagonalizing the O matrix
REAL(kind=DP) :: pmat_cutoff
!! cutoff (in Ryd) for polarization diagonalization
INTEGER :: pmat_type
!! type of approximation 1 usual, 2 with wanniers, 3 with optimal representation,5 just plane waves
INTEGER :: n_fast_pmat
!! number of states for fast evaluation of conduction manifold if =0 disabled
INTEGER :: n_pmat
!! number of orthonormal states for optimal representation O matrix
REAL(kind=DP) :: s_pmat
!! cutoff for optimal basis for O matrix
INTEGER :: lanczos_restart
!! restart point for lanczos
INTEGER :: n_pola_lanczos_eff
!! effective number of pola states; if 0 equal to n_pola_lanczos
INTEGER :: n_self_lanczos_eff
!! effective number of self states; if 0 equal to n_self_lanczos
REAL(kind=DP) :: off_fast_pmat
!! offset in Ry for fast assessment of polarizability if =0 disabled
LOGICAL :: l_fast_pola
!! if TRUE fast assessment of polarizability for basis construction
LOGICAL :: l_v_basis
!! if TRUE valuate the polarizability basis vectors as eigenstates of v operator
REAL(kind=DP) :: v_cutoff
!! cutoff in Ryd for v operator
LOGICAL :: l_iter_algorithm
!! if TRUE uses iterative algorithms
REAL(kind=DP) :: dual_pb
!! dual value till 4.d0 for defing the grid on which the polarizability basis is created
REAL(kind=DP), ALLOCATABLE :: vg_q(:)
!! contains the elements V(G) of the Coulomb potential obtained upon integration over q
LOGICAL :: l_t_wannier
!! if TRUE builds t verctors starting from KS valence wannier functions
REAL(kind=DP) :: dual_vt
!! dual value till 4.d0 for defing the grid on which the t vectors created
REAL(kind=DP) :: dual_vs
!! dual value till 4.d0 for defing the grid on which the s vectors created
LOGICAL :: lwannier
!! if TRUE take advantage of localization of wannier functions
REAL(kind=DP) :: wannier_thres
!! threshold for modulus of wannier function in a.u.
INTEGER :: s_first_state
!! if different from 0, first KS state for calculatin s vectors (if last 1)
INTEGER :: s_last_state
!! if different from 0, last KS state for calculatin s vectors (if last num_nbnds)
LOGICAL :: l_selfconsistent
!! if TRUE do selfconsistent GW calculation, requires file band.dat
REAL(kind=DP), ALLOCATABLE :: ene_gw(:,:)
!! GW energies of previous iteration for selfconsistent calculation
INTEGER :: n_gw_states
!! number of GW states for selfconsistent calculation
REAL(kind=DP) :: delta_self
!! delta energy for selfconsistent calculation
LOGICAL :: l_whole_s
!! if TRUE calculates also the off-diagonal elemenets of V\_xc for then
!! calculating the off-diagonal elements of sigma
LOGICAL :: l_ts_eigen
!! if TRUE the t and global vectors are calculated considering also the eigenvalues of the partial basis (recommanded)
LOGICAL :: l_frac_occ
!! if TRUE consider fractional occupancies
INTEGER :: num_nbndv_min(2)
!! limits for fully occupied states
LOGICAL :: l_cond_pol_base
!! if TRUE uses conduction states till num_nbnds for the construction of the polarizability bases
LOGICAL :: l_semicore
!! if TRUE evaluate semicore terms
INTEGER :: n_semicore
!! number of semicore states staring from the bottom of valence states
LOGICAL :: l_semicore_read
!! if TRUE reads semicore file for calculating products for Green's function
LOGICAL :: l_verbose
!! if TRUE a lot of ouput for debug
LOGICAL :: l_contour
!! if TRUE calculates the terms for contour integration
LOGICAL :: l_real
!! if TRUE calculate the polarizability basis, s and t vectors avoiding ffts it requires more memory
LOGICAL :: l_big_system
!! if TRUE uses startegy for large systems: just local s vectors are used
REAL(kind=DP) ::extra_pw_cutoff
!! cutoff to add to the optimal polarizability basis plane-waves (sin and cos functions)
!! if 0 no plane waves is added
!REAL(kind=DP) :: exchange_fast_dual!for defining the fast exchange routines
LOGICAL :: l_bse
!! if TRUE computing quantities for bse calculation
REAL(kind=DP) :: s_bse
!! threshold for wannier function overlap
REAL(kind=DP) :: dual_bse
!! dual factor for bse calculations
LOGICAL :: l_simple
!! if TRUE writes on disk polarizability basis on real space for further post-processing
LOGICAL :: l_list
!! if TRUE uses startegy for large systems from list of states included in s_first_state, s_last_state
INTEGER :: n_list(2)
!! number of states in list for the 2 spin channels
INTEGER, ALLOCATABLE :: i_list(:,:)
!! list of KS states to be computed
LOGICAL :: l_full
!! if TRUE prepare data for further post-processing for a full-relativistic calculation
INTEGER :: n_full(2)
!! numeber of proper relativistic states in G of GW for collinear spin channel
!variables for splitting the head calculation in blocks in order to reduce memory usage
!no effect on results
INTEGER :: len_head_block_freq
!! length of blocks on frequency
INTEGER :: len_head_block_wfc
!! length of blocks on unperturbed occupied wfcs
! JDE
LOGICAL :: l_no_GW_just_screening ! When true use strategy to compute screening via iterative minimization
LOGICAL :: l_no_GW_bare_coulomb ! When true only do not compute correlation part of W for just_screening
INTEGER :: no_GW_cg_maxit ! Maximum number of conj. grad. steps in calculation of (1-vP) operator
REAL(KIND=DP) :: no_GW_cg_threshold ! Convergence threshold for conj. grad. calculation of (1-vP) operator
COMPLEX(KIND=DP), ALLOCATABLE :: ewvc(:,:,:)
! JDE
LOGICAL :: l_easy
!!if true calculate GW with the EASY strategy , default: false
LOGICAL :: l_easy_lanczos_g
!if true useus Lanczos for EASY strategy instead of DFPT for G, default: true
INTEGER :: easy_grid_type
!!0= maximum point,1= equally spaced points
INTEGER :: easy_grid_param(5)
!!only for easy_grid_type==1:
!![1-3], offset along x,y,z,
!![4] spacing separation
!!default: [0,0,0,4]
INTEGER :: easy_average_type
!!method used
!!0 weighted sums, 1 simple sums
REAL(kind=DP) :: easy_psi_thrs
!!threshold on absolute values of the wavefunction for easy_grid_type==1 (default 0.)
LOGICAL :: l_easy_update_basis_w
!!if .true. the Lanczos basis for W is updated at each iterative step for W, default: .false.
LOGICAL :: l_easy_dielectric_constant
!!if .true. calculte the dielectric constan, default: .false.
REAL(kind=DP) :: easy_w_update_alpha
!!factor for decremeting force in SD algorithm, default: 0.1
REAL(kind=DP) :: easy_w_update_lanczos
!!threshold for updating lanczos chain in W, default: 0.5
REAL(kind=DP) :: easy_w_thrs
!!threshold for W convergenze, default 1d-20
INTEGER :: easy_split_calc_n
!!number of concurrent easy calcuation, default 1
INTEGER :: easy_split_calc_i
!!progressive number of actual concurrent easy calcuation, default 1
LOGICAL :: l_easy_w_disk
!!if true read w from disk
INTEGER :: s_first_spin
!!if different from 0, first KS spin state for calculatin s vectors
!!otherwise 1
INTEGER :: s_last_spin
!!if different from 0, last KS spin state for calculatin s vectors
!!otherwise nspin
INTERFACE free_memory
MODULE PROCEDURE free_complex,free_real
END INTERFACE
CONTAINS
subroutine free_complex( c)
implicit none
type(complex_matrix_pointer) :: c
deallocate(c%p)
return
end subroutine
subroutine free_real( r)
implicit none
type(real_matrix_pointer) :: r
deallocate(r%p)
return
end subroutine
subroutine max_ngm_set
!! set the value of max\_ngm
use io_global, only : stdout
use gvect, only : ngm,gg
use cell_base, only : tpiba2
implicit none
integer :: ig
max_ngm=0
do ig=1,ngm
if(gg(ig)*tpiba2 >= ecutoff_global) exit
max_ngm=max_ngm+1
enddo
write(stdout,*) 'MAX_NGM:', max_ngm, ngm
end subroutine max_ngm_set
END MODULE wannier_gw