Line data    Source code

       1             : !--------------------------------------------------------------------------------------------------!
       2             : !   CP2K: A general program to perform molecular dynamics simulations                              !
       3             : !   Copyright 2000-2025 CP2K developers group <https://cp2k.org>                                   !
       4             : !                                                                                                  !
       5             : !   SPDX-License-Identifier: GPL-2.0-or-later                                                      !
       6             : !--------------------------------------------------------------------------------------------------!
       7             : 
       8             : ! **************************************************************************************************
       9             : !> \brief Original matrix exponential parametrization
      10             : !> \author Ole Schuett
      11             : ! **************************************************************************************************
      12             : MODULE pao_param_exp
      13             :    USE basis_set_types,                 ONLY: gto_basis_set_type
      14             :    USE cp_dbcsr_api,                    ONLY: &
      15             :         dbcsr_create, dbcsr_get_block_p, dbcsr_get_info, dbcsr_iterator_blocks_left, &
      16             :         dbcsr_iterator_next_block, dbcsr_iterator_start, dbcsr_iterator_stop, dbcsr_iterator_type, &
      17             :         dbcsr_p_type, dbcsr_release, dbcsr_reserve_diag_blocks, dbcsr_set, dbcsr_type
      18             :    USE dm_ls_scf_types,                 ONLY: ls_scf_env_type
      19             :    USE kinds,                           ONLY: dp
      20             :    USE mathlib,                         ONLY: diag_antisym,&
      21             :                                               diamat_all
      22             :    USE pao_param_methods,               ONLY: pao_calc_AB_from_U,&
      23             :                                               pao_calc_grad_lnv_wrt_U
      24             :    USE pao_potentials,                  ONLY: pao_guess_initial_potential
      25             :    USE pao_types,                       ONLY: pao_env_type
      26             :    USE qs_environment_types,            ONLY: get_qs_env,&
      27             :                                               qs_environment_type
      28             :    USE qs_kind_types,                   ONLY: get_qs_kind,&
      29             :                                               qs_kind_type
      30             : #include "./base/base_uses.f90"
      31             : 
      32             :    IMPLICIT NONE
      33             : 
      34             :    PRIVATE
      35             : 
      36             :    CHARACTER(len=*), PARAMETER, PRIVATE :: moduleN = 'pao_param_exp'
      37             : 
      38             :    PUBLIC :: pao_param_init_exp, pao_param_finalize_exp, pao_calc_AB_exp
      39             :    PUBLIC :: pao_param_count_exp, pao_param_initguess_exp
      40             : 
      41             : CONTAINS
      42             : 
      43             : ! **************************************************************************************************
      44             : !> \brief Initialize matrix exponential parametrization
      45             : !> \param pao ...
      46             : !> \param qs_env ...
      47             : ! **************************************************************************************************
      48          24 :    SUBROUTINE pao_param_init_exp(pao, qs_env)
      49             :       TYPE(pao_env_type), POINTER                        :: pao
      50             :       TYPE(qs_environment_type), POINTER                 :: qs_env
      51             : 
      52             :       CHARACTER(len=*), PARAMETER :: routineN = 'pao_param_init_exp'
      53             : 
      54             :       INTEGER                                            :: acol, arow, handle, iatom, N
      55             :       LOGICAL                                            :: found
      56          24 :       REAL(dp), DIMENSION(:), POINTER                    :: H_evals
      57          24 :       REAL(dp), DIMENSION(:, :), POINTER                 :: block_H, block_H0, block_N, block_U0, &
      58          24 :                                                             block_V0, H_evecs
      59             :       TYPE(dbcsr_iterator_type)                          :: iter
      60          24 :       TYPE(dbcsr_p_type), DIMENSION(:), POINTER          :: matrix_s
      61             : 
      62          24 :       CALL timeset(routineN, handle)
      63             : 
      64          24 :       CALL get_qs_env(qs_env, matrix_s=matrix_s)
      65             : 
      66             :       ! allocate matrix_U0
      67             :       CALL dbcsr_create(pao%matrix_U0, &
      68             :                         name="PAO matrix_U0", &
      69             :                         matrix_type="N", &
      70             :                         dist=pao%diag_distribution, &
      71          24 :                         template=matrix_s(1)%matrix)
      72          24 :       CALL dbcsr_reserve_diag_blocks(pao%matrix_U0)
      73             : 
      74             :       ! diagonalize each block of H0 and store eigenvectors in U0
      75             : !$OMP PARALLEL DEFAULT(NONE) SHARED(pao,qs_env) &
      76          24 : !$OMP PRIVATE(iter,arow,acol,iatom,N,found,block_H0,block_V0,block_N,block_H,block_U0,H_evecs,H_evals)
      77             :       CALL dbcsr_iterator_start(iter, pao%matrix_U0)
      78             :       DO WHILE (dbcsr_iterator_blocks_left(iter))
      79             :          CALL dbcsr_iterator_next_block(iter, arow, acol, block_U0)
      80             :          iatom = arow; CPASSERT(arow == acol)
      81             :          CALL dbcsr_get_block_p(matrix=pao%matrix_H0, row=iatom, col=iatom, block=block_H0, found=found)
      82             :          CALL dbcsr_get_block_p(matrix=pao%matrix_N_diag, row=iatom, col=iatom, block=block_N, found=found)
      83             :          CPASSERT(ASSOCIATED(block_H0) .AND. ASSOCIATED(block_N))
      84             :          N = SIZE(block_U0, 1)
      85             : 
      86             :          ALLOCATE (block_V0(N, N))
      87             :          CALL pao_guess_initial_potential(qs_env, iatom, block_V0)
      88             : 
      89             :          ! construct H
      90             :          ALLOCATE (block_H(N, N))
      91             :          block_H = MATMUL(MATMUL(block_N, block_H0 + block_V0), block_N) ! transform into orthonormal basis
      92             : 
      93             :          ! diagonalize H
      94             :          ALLOCATE (H_evecs(N, N), H_evals(N))
      95             :          H_evecs = block_H
      96             :          CALL diamat_all(H_evecs, H_evals)
      97             : 
      98             :          ! use eigenvectors as initial guess
      99             :          block_U0 = H_evecs
     100             : 
     101             :          DEALLOCATE (block_H, H_evecs, H_evals, block_V0)
     102             :       END DO
     103             :       CALL dbcsr_iterator_stop(iter)
     104             : !$OMP END PARALLEL
     105             : 
     106          24 :       IF (pao%precondition) &
     107           0 :          CPABORT("PAO preconditioning not supported for selected parametrization.")
     108             : 
     109          24 :       CALL timestop(handle)
     110          24 :    END SUBROUTINE pao_param_init_exp
     111             : 
     112             : ! **************************************************************************************************
     113             : !> \brief Finalize exponential parametrization
     114             : !> \param pao ...
     115             : ! **************************************************************************************************
     116          24 :    SUBROUTINE pao_param_finalize_exp(pao)
     117             :       TYPE(pao_env_type), POINTER                        :: pao
     118             : 
     119          24 :       CALL dbcsr_release(pao%matrix_U0)
     120             : 
     121          24 :    END SUBROUTINE pao_param_finalize_exp
     122             : 
     123             : ! **************************************************************************************************
     124             : !> \brief Returns the number of parameters for given atomic kind
     125             : !> \param qs_env ...
     126             : !> \param ikind ...
     127             : !> \param nparams ...
     128             : ! **************************************************************************************************
     129         128 :    SUBROUTINE pao_param_count_exp(qs_env, ikind, nparams)
     130             :       TYPE(qs_environment_type), POINTER                 :: qs_env
     131             :       INTEGER, INTENT(IN)                                :: ikind
     132             :       INTEGER, INTENT(OUT)                               :: nparams
     133             : 
     134             :       INTEGER                                            :: cols, pao_basis_size, pri_basis_size, &
     135             :                                                             rows
     136             :       TYPE(gto_basis_set_type), POINTER                  :: basis_set
     137          64 :       TYPE(qs_kind_type), DIMENSION(:), POINTER          :: qs_kind_set
     138             : 
     139          64 :       CALL get_qs_env(qs_env, qs_kind_set=qs_kind_set)
     140             :       CALL get_qs_kind(qs_kind_set(ikind), &
     141             :                        basis_set=basis_set, &
     142          64 :                        pao_basis_size=pao_basis_size)
     143          64 :       pri_basis_size = basis_set%nsgf
     144             : 
     145             :       ! we only consider rotations between occupied and virtuals
     146          64 :       rows = pao_basis_size
     147          64 :       cols = pri_basis_size - pao_basis_size
     148          64 :       nparams = rows*cols
     149             : 
     150          64 :    END SUBROUTINE pao_param_count_exp
     151             : 
     152             : ! **************************************************************************************************
     153             : !> \brief Fills matrix_X with an initial guess
     154             : !> \param pao ...
     155             : ! **************************************************************************************************
     156          14 :    SUBROUTINE pao_param_initguess_exp(pao)
     157             :       TYPE(pao_env_type), POINTER                        :: pao
     158             : 
     159          14 :       CALL dbcsr_set(pao%matrix_X, 0.0_dp) ! actual initial guess is matrix_U0
     160             : 
     161          14 :    END SUBROUTINE pao_param_initguess_exp
     162             : 
     163             : ! **************************************************************************************************
     164             : !> \brief Takes current matrix_X and calculates the matrices A and B.
     165             : !> \param pao ...
     166             : !> \param qs_env ...
     167             : !> \param ls_scf_env ...
     168             : !> \param gradient ...
     169             : ! **************************************************************************************************
     170        2710 :    SUBROUTINE pao_calc_AB_exp(pao, qs_env, ls_scf_env, gradient)
     171             :       TYPE(pao_env_type), POINTER                        :: pao
     172             :       TYPE(qs_environment_type), POINTER                 :: qs_env
     173             :       TYPE(ls_scf_env_type), TARGET                      :: ls_scf_env
     174             :       LOGICAL, INTENT(IN)                                :: gradient
     175             : 
     176             :       CHARACTER(len=*), PARAMETER                        :: routineN = 'pao_calc_AB_exp'
     177             : 
     178             :       INTEGER                                            :: handle
     179        2710 :       TYPE(dbcsr_p_type), DIMENSION(:), POINTER          :: matrix_s
     180             :       TYPE(dbcsr_type)                                   :: matrix_M, matrix_U
     181             : 
     182        2710 :       CALL timeset(routineN, handle)
     183        2710 :       CALL get_qs_env(qs_env, matrix_s=matrix_s)
     184        2710 :       CALL dbcsr_create(matrix_U, matrix_type="N", dist=pao%diag_distribution, template=matrix_s(1)%matrix)
     185        2710 :       CALL dbcsr_reserve_diag_blocks(matrix_U)
     186             : 
     187             :       !TODO: move this condition into pao_calc_U, use matrix_N as template
     188        2710 :       IF (gradient) THEN
     189         488 :          CALL pao_calc_grad_lnv_wrt_U(qs_env, ls_scf_env, matrix_M)
     190         488 :          CALL pao_calc_U_exp(pao, matrix_U, matrix_M, pao%matrix_G)
     191         488 :          CALL dbcsr_release(matrix_M)
     192             :       ELSE
     193        2222 :          CALL pao_calc_U_exp(pao, matrix_U)
     194             :       END IF
     195             : 
     196        2710 :       CALL pao_calc_AB_from_U(pao, qs_env, ls_scf_env, matrix_U)
     197        2710 :       CALL dbcsr_release(matrix_U)
     198        2710 :       CALL timestop(handle)
     199        2710 :    END SUBROUTINE pao_calc_AB_exp
     200             : 
     201             : ! **************************************************************************************************
     202             : !> \brief Calculate new matrix U and optionally its gradient G
     203             : !> \param pao ...
     204             : !> \param matrix_U ...
     205             : !> \param matrix_M ...
     206             : !> \param matrix_G ...
     207             : ! **************************************************************************************************
     208        2710 :    SUBROUTINE pao_calc_U_exp(pao, matrix_U, matrix_M, matrix_G)
     209             :       TYPE(pao_env_type), POINTER                        :: pao
     210             :       TYPE(dbcsr_type)                                   :: matrix_U
     211             :       TYPE(dbcsr_type), OPTIONAL                         :: matrix_M, matrix_G
     212             : 
     213             :       CHARACTER(len=*), PARAMETER                        :: routineN = 'pao_calc_U_exp'
     214             : 
     215             :       COMPLEX(dp)                                        :: denom
     216        2710 :       COMPLEX(dp), DIMENSION(:), POINTER                 :: evals
     217        2710 :       COMPLEX(dp), DIMENSION(:, :), POINTER              :: block_D, evecs
     218             :       INTEGER                                            :: acol, arow, handle, i, iatom, j, k, M, &
     219             :                                                             N, nparams
     220        2710 :       INTEGER, DIMENSION(:), POINTER                     :: blk_sizes_pao, blk_sizes_pri
     221             :       LOGICAL                                            :: found
     222        2710 :       REAL(dp), DIMENSION(:, :), POINTER                 :: block_G, block_G_full, block_M, &
     223        2710 :                                                             block_tmp, block_U, block_U0, block_X, &
     224        2710 :                                                             block_X_full
     225             :       TYPE(dbcsr_iterator_type)                          :: iter
     226             : 
     227        2710 :       CALL timeset(routineN, handle)
     228             : 
     229        2710 :       CALL dbcsr_get_info(pao%matrix_Y, row_blk_size=blk_sizes_pri, col_blk_size=blk_sizes_pao)
     230             : 
     231             : !$OMP PARALLEL DEFAULT(NONE) SHARED(pao,matrix_U,matrix_M,matrix_G,blk_sizes_pri,blk_sizes_pao) &
     232             : !$OMP PRIVATE(iter,arow,acol,iatom,N,M,nparams,i,j,k,found) &
     233             : !$OMP PRIVATE(block_X,block_U,block_U0,block_X_full,evals,evecs) &
     234        2710 : !$OMP PRIVATE(block_M,block_G,block_D,block_tmp,block_G_full,denom)
     235             :       CALL dbcsr_iterator_start(iter, pao%matrix_X)
     236             :       DO WHILE (dbcsr_iterator_blocks_left(iter))
     237             :          CALL dbcsr_iterator_next_block(iter, arow, acol, block_X)
     238             :          iatom = arow; CPASSERT(arow == acol)
     239             :          CALL dbcsr_get_block_p(matrix=matrix_U, row=iatom, col=iatom, block=block_U, found=found)
     240             :          CPASSERT(ASSOCIATED(block_U))
     241             :          CALL dbcsr_get_block_p(matrix=pao%matrix_U0, row=iatom, col=iatom, block=block_U0, found=found)
     242             :          CPASSERT(ASSOCIATED(block_U0))
     243             : 
     244             :          N = blk_sizes_pri(iatom) ! size of primary basis
     245             :          M = blk_sizes_pao(iatom) ! size of pao basis
     246             :          nparams = SIZE(block_X, 1)
     247             : 
     248             :          ! block_X stores only rotations between occupied and virtuals
     249             :          ! hence, we first have to build the full anti-symmetric exponent block
     250             :          ALLOCATE (block_X_full(N, N))
     251             :          block_X_full(:, :) = 0.0_dp
     252             :          DO i = 1, nparams
     253             :             block_X_full(MOD(i - 1, M) + 1, M + (i - 1)/M + 1) = +block_X(i, 1)
     254             :             block_X_full(M + (i - 1)/M + 1, MOD(i - 1, M) + 1) = -block_X(i, 1)
     255             :          END DO
     256             : 
     257             :          ! diagonalize block_X_full
     258             :          ALLOCATE (evals(N), evecs(N, N))
     259             :          CALL diag_antisym(block_X_full, evecs, evals)
     260             : 
     261             :          ! construct rotation matrix
     262             :          block_U(:, :) = 0.0_dp
     263             :          DO k = 1, N
     264             :             DO i = 1, N
     265             :                DO j = 1, N
     266             :                   block_U(i, j) = block_U(i, j) + REAL(EXP(evals(k))*evecs(i, k)*CONJG(evecs(j, k)), dp)
     267             :                END DO
     268             :             END DO
     269             :          END DO
     270             : 
     271             :          block_U = MATMUL(block_U0, block_U) ! prepend initial guess rotation
     272             : 
     273             :          ! TURNING POINT (if calc grad) ------------------------------------------
     274             :          IF (PRESENT(matrix_G)) THEN
     275             :             CPASSERT(PRESENT(matrix_M))
     276             : 
     277             :             CALL dbcsr_get_block_p(matrix=pao%matrix_G, row=iatom, col=iatom, block=block_G, found=found)
     278             :             CPASSERT(ASSOCIATED(block_G))
     279             :             CALL dbcsr_get_block_p(matrix=matrix_M, row=iatom, col=iatom, block=block_M, found=found)
     280             :             ! don't check ASSOCIATED(block_M), it might have been filtered out.
     281             : 
     282             :             ALLOCATE (block_D(N, N), block_tmp(N, N), block_G_full(N, N))
     283             :             DO i = 1, N
     284             :                DO j = 1, N
     285             :                   denom = evals(i) - evals(j)
     286             :                   IF (i == j) THEN
     287             :                      block_D(i, i) = EXP(evals(i)) ! diagonal elements
     288             :                   ELSE IF (ABS(denom) > 1e-10_dp) THEN
     289             :                      block_D(i, j) = (EXP(evals(i)) - EXP(evals(j)))/denom
     290             :                   ELSE
     291             :                      block_D(i, j) = 1.0_dp ! limit according to L'Hospital's rule
     292             :                   END IF
     293             :                END DO
     294             :             END DO
     295             : 
     296             :             IF (ASSOCIATED(block_M)) THEN
     297             :                block_tmp = MATMUL(TRANSPOSE(block_U0), block_M)
     298             :             ELSE
     299             :                block_tmp = 0.0_dp
     300             :             END IF
     301             :             block_G_full = fold_derivatives(block_tmp, block_D, evecs)
     302             : 
     303             :             ! return only gradient for rotations between occupied and virtuals
     304             :             DO i = 1, nparams
     305             :                block_G(i, 1) = 2.0_dp*block_G_full(MOD(i - 1, M) + 1, M + (i - 1)/M + 1)
     306             :             END DO
     307             : 
     308             :             DEALLOCATE (block_D, block_tmp, block_G_full)
     309             :          END IF
     310             : 
     311             :          DEALLOCATE (block_X_full, evals, evecs)
     312             : 
     313             :       END DO
     314             :       CALL dbcsr_iterator_stop(iter)
     315             : !$OMP END PARALLEL
     316             : 
     317        2710 :       CALL timestop(handle)
     318        2710 :    END SUBROUTINE pao_calc_U_exp
     319             : 
     320             : ! **************************************************************************************************
     321             : !> \brief Helper routine, for calculating derivatives
     322             : !> \param M ...
     323             : !> \param D ...
     324             : !> \param R ...
     325             : !> \return ...
     326             : ! **************************************************************************************************
     327         683 :    FUNCTION fold_derivatives(M, D, R) RESULT(G)
     328             :       REAL(dp), DIMENSION(:, :), INTENT(IN)              :: M
     329             :       COMPLEX(dp), DIMENSION(:, :), INTENT(IN)           :: D, R
     330             :       REAL(dp), DIMENSION(SIZE(M, 1), SIZE(M, 1))        :: G
     331             : 
     332         683 :       COMPLEX(dp), DIMENSION(:, :), POINTER              :: F, RF, RM, RMR
     333             :       INTEGER                                            :: n
     334         683 :       REAL(dp), DIMENSION(:, :), POINTER                 :: RFR
     335             : 
     336         683 :       n = SIZE(M, 1)
     337             : 
     338        8879 :       ALLOCATE (RM(n, n), RMR(n, n), F(n, n), RF(n, n), RFR(n, n))
     339             : 
     340      642537 :       RM = MATMUL(TRANSPOSE(CONJG(R)), TRANSPOSE(M))
     341     1133318 :       RMR = MATMUL(RM, R)
     342      101626 :       F = RMR*D !Hadamard product
     343      641854 :       RF = MATMUL(R, F)
     344     1133318 :       RFR = REAL(MATMUL(RF, TRANSPOSE(CONJG(R))), dp)
     345             : 
     346             :       ! gradient dE/dX has to be anti-symmetric
     347       50813 :       G = 0.5_dp*(TRANSPOSE(RFR) - RFR)
     348             : 
     349         683 :       DEALLOCATE (RM, RMR, F, RF, RFR)
     350         683 :    END FUNCTION fold_derivatives
     351             : 
     352         683 : END MODULE pao_param_exp