quantum-espresso/Modules/wannier_gw.f90

258 lines
11 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 .
!
!--------------------------------------------------------------------------
!
MODULE wannier_gw
!
! ... The variables needed for gww-gwl code (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)!see above
!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 e 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 exchnage 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
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