Line data Source code
1 : !!****m* ABINIT/m_rttddft_driver
2 : !! NAME
3 : !! m_rttddft_driver
4 : !!
5 : !! FUNCTION
6 : !! Real-Time Time Dependent DFT (RT-TDDFT)
7 : !!
8 : !! COPYRIGHT
9 : !! Copyright (C) 2021-2026 ABINIT group (FB)
10 : !! This file is distributed under the terms of the
11 : !! GNU General Public License, see ~abinit/COPYING
12 : !! or http://www.gnu.org/copyleft/gpl.txt .
13 : !!
14 : !! SOURCE
15 :
16 : #if defined HAVE_CONFIG_H
17 : #include "config.h"
18 : #endif
19 :
20 : #include "abi_common.h"
21 :
22 : module m_rttddft_driver
23 :
24 : use defs_basis
25 : use defs_abitypes, only: MPI_type
26 : use defs_datatypes, only: pseudopotential_type
27 : use m_dtfil, only: datafiles_type
28 : use m_dtset, only: dataset_type
29 : use m_errors, only: msg_hndl
30 : use m_pawang, only: pawang_type
31 : use m_pawrad, only: pawrad_type
32 : use m_pawtab, only: pawtab_type
33 : use m_rttddft_output, only: rttddft_output
34 : use m_rttddft_tdks, only: tdks_type
35 : use m_rttddft_propagate, only: rttddft_propagate_ele
36 : use m_rttddft_properties, only: rttddft_calc_density, &
37 : & rttddft_calc_etot, &
38 : & rttddft_calc_current
39 : use m_specialmsg, only: wrtout
40 : use m_time, only: cwtime
41 :
42 : implicit none
43 :
44 : private
45 : !!***
46 :
47 : public :: rttddft
48 : !!***
49 :
50 : contains
51 : !!***
52 :
53 : !!****f* m_rttddft_driver/rttddft
54 : !! NAME
55 : !! rttddft
56 : !!
57 : !! FUNCTION
58 : !! Primary routine for real-time TDDFT calculations.
59 : !! 1) Initialization: create main tdks (Time-Dependent Kohn-Sham) object
60 : !! - intialize various important parameters
61 : !! - read intial KS orbitals in WFK file
62 : !! - compute initial density from KS orbitals
63 : !! 2) Propagation loop (rttddft_propagate):
64 : !! for i = 1, ntime
65 : !! - propagate KS orbitals
66 : !! - propagate nuclei if requested (Erhenfest dynamics)
67 : !! - compute new density
68 : !! - Compute and print requested properties
69 : !! 3) Final printout and finalize
70 : !!
71 : !! INPUTS
72 : !! codvsn = code version
73 : !! dtfil <type datafiles_type> = infos about file names
74 : !! dtset <type(dataset_type)> = all input variables for this dataset
75 : !! mpi_enreg <MPI_type> = MPI-parallelisation information
76 : !! pawang <type(pawang_type)> = paw angular mesh and related data
77 : !! pawrad(ntypat*usepaw) <type(pawrad_type)> = paw radial mesh and related data
78 : !! pawtab(ntypat*usepaw) <type(pawtab_type)> = paw tabulated starting data
79 : !! psps <type(pseudopotential_type)> = variables related to pseudopotentials
80 : !!
81 : !! OUTPUT
82 : !!
83 : !! SOURCE
84 50 : subroutine rttddft(codvsn,dtfil,dtset,mpi_enreg,pawang,pawrad,pawtab,psps)
85 :
86 : !Arguments ------------------------------------
87 : !scalars
88 : character(len=8), intent(in) :: codvsn
89 : type(dataset_type), intent(inout) :: dtset
90 : type(datafiles_type), intent(inout) :: dtfil
91 : type(MPI_type), intent(inout) :: mpi_enreg
92 : type(pawang_type), intent(inout) :: pawang
93 : type(pseudopotential_type), intent(inout) :: psps
94 : !arrays
95 : type(pawrad_type), target, intent(inout) :: pawrad(psps%ntypat*psps%usepaw)
96 : type(pawtab_type), target, intent(inout) :: pawtab(psps%ntypat*psps%usepaw)
97 :
98 : !Local variables-------------------------------
99 : !scalars
100 : character(len=500) :: msg
101 : integer :: istep
102 : real(dp) :: integrated_density, stability
103 50 : type(tdks_type) :: tdks
104 : !arrays
105 : real(dp) :: cpu, wall, gflops
106 :
107 : ! ***********************************************************************
108 :
109 50 : write(msg,'(7a)') ch10,'---------------------------------------------------------------------------',&
110 50 : & ch10,'---------------- Starting real-time time dependent DFT ----------------',&
111 100 : & ch10,'---------------------------------------------------------------------------',ch10
112 50 : call wrtout(ab_out,msg)
113 50 : if (do_write_log) call wrtout(std_out,msg)
114 50 : write(msg,'(7a)') ch10,' RT-TDDFT is under active development and should thus be used with caution ',&
115 100 : & ch10,'---------------------------------------------------------------------------',ch10
116 50 : if (do_write_log) call wrtout(std_out,msg)
117 :
118 : !** 1) Initialization: create main tdks (Time-Dependent Kohn-Sham) object
119 50 : write(msg,'(3a)') ch10,'--------------------------- Initialization ----------------------------',ch10
120 50 : call wrtout(ab_out,msg)
121 50 : if (do_write_log) call wrtout(std_out,msg)
122 :
123 50 : call tdks%init(codvsn,dtfil,dtset,mpi_enreg,pawang,pawrad,pawtab,psps)
124 :
125 : !Compute initial electronic density
126 50 : call rttddft_calc_density(dtset,mpi_enreg,psps,tdks)
127 :
128 : !Compute current at t=0 (or t-dt) and update vector potential accordingly
129 50 : if (dtset%prtcurrent/=0 .or. tdks%tdef%induced_vecpot) then
130 21 : call rttddft_calc_current(tdks,dtset,dtfil,psps,mpi_enreg)
131 : end if
132 :
133 : !** 2) Propagation loop
134 50 : write(msg,'(3a)') ch10,'------------------------- Starting propagation ------------------------',ch10
135 50 : call wrtout(ab_out,msg)
136 50 : if (do_write_log) call wrtout(std_out,msg)
137 :
138 1774 : do istep = tdks%first_step, tdks%first_step+tdks%ntime-1
139 :
140 1725 : call cwtime(cpu,wall,gflops,"start")
141 :
142 : !*** Perform electronic step ***
143 : !Compute new WF at time t and energy contribution at time t-dt
144 1725 : call rttddft_propagate_ele(dtset,istep,mpi_enreg,psps,tdks)
145 :
146 : !Compute total energy at time t-dt
147 1725 : call rttddft_calc_etot(dtset,tdks%energies,tdks%etot,tdks%occ)
148 :
149 : !Update electric field and vector potential value
150 : call tdks%tdef%update(dtset,mpi_enreg,istep*tdks%dt,tdks%rprimd,tdks%gprimd,tdks%kg, &
151 1725 : & psps%mpsang,tdks%npwarr,tdks%ylm,tdks%ylmgr,tdks%current)
152 :
153 : !Compute new electronic density at t
154 1725 : call rttddft_calc_density(dtset,mpi_enreg,psps,tdks)
155 :
156 : !Compute current at t
157 1725 : if (dtset%prtcurrent/=0 .or. tdks%tdef%induced_vecpot) then
158 1100 : call rttddft_calc_current(tdks,dtset,dtfil,psps,mpi_enreg)
159 : end if
160 :
161 : !Compute and output useful electronic values
162 1725 : call rttddft_output(dtfil,dtset,istep,mpi_enreg,psps,tdks)
163 :
164 : !Test of stability
165 29324940 : integrated_density = sum(tdks%rhor(:,1))*tdks%ucvol/tdks%nfftf
166 1725 : stability = abs(integrated_density-dtset%nelect)/dtset%nelect
167 1725 : if (stability > 0.1_dp) then
168 1 : write(msg,"(3a)") "The integrated density has changed by more than 10%!", ch10, &
169 2 : & "The integration is unstable, you should probably decrease the timestep dtele."
170 1 : ABI_ERROR(msg)
171 1724 : else if (stability > 0.05_dp) then
172 1 : write(msg,"(3a)") "The integrated density has changed by more than 5%!", ch10, &
173 2 : & "You should be careful, the integration might be unstable"
174 1 : ABI_WARNING(msg)
175 : end if
176 :
177 : !TODO: *** Perform nuclear step ***
178 : ! For Ehrenfest dynamics
179 : !call rttddft_propagate_nuc(dtset,istep,mpi_enreg,psps,tdks)
180 :
181 1724 : call cwtime(cpu,wall,gflops,"stop")
182 1724 : write(msg,'(a,2f8.2,a)') '- Time - cpu, wall (sec):', cpu, wall, ch10
183 1724 : call wrtout(ab_out,msg)
184 5222 : if (do_write_log) call wrtout(std_out,msg)
185 :
186 : end do
187 :
188 : !** 3) Final Output and free memory
189 49 : write(msg,'(7a)') ch10,'---------------------------------------------------------------------------',&
190 49 : & ch10,'---------------- Finished real-time time dependent DFT ----------------',&
191 98 : & ch10,'---------------------------------------------------------------------------',ch10
192 49 : call wrtout(ab_out,msg)
193 49 : if (do_write_log) call wrtout(std_out,msg)
194 :
195 49 : call tdks%free(dtset,mpi_enreg,psps)
196 :
197 49 : end subroutine rttddft
198 : !!***
199 :
200 : end module m_rttddft_driver
201 : !!***
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