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_set, dbcsr_type
      18             :    USE cp_dbcsr_contrib,                ONLY: dbcsr_reserve_diag_blocks
      19             :    USE dm_ls_scf_types,                 ONLY: ls_scf_env_type
      20             :    USE kinds,                           ONLY: dp
      21             :    USE mathlib,                         ONLY: diag_antisym,&
      22             :                                               diamat_all
      23             :    USE pao_param_methods,               ONLY: pao_calc_AB_from_U,&
      24             :                                               pao_calc_grad_lnv_wrt_U
      25             :    USE pao_potentials,                  ONLY: pao_guess_initial_potential
      26             :    USE pao_types,                       ONLY: pao_env_type
      27             :    USE qs_environment_types,            ONLY: get_qs_env,&
      28             :                                               qs_environment_type
      29             :    USE qs_kind_types,                   ONLY: get_qs_kind,&
      30             :                                               qs_kind_type
      31             : #include "./base/base_uses.f90"
      32             : 
      33             :    IMPLICIT NONE
      34             : 
      35             :    PRIVATE
      36             : 
      37             :    CHARACTER(len=*), PARAMETER, PRIVATE :: moduleN = 'pao_param_exp'
      38             : 
      39             :    PUBLIC :: pao_param_init_exp, pao_param_finalize_exp, pao_calc_AB_exp
      40             :    PUBLIC :: pao_param_count_exp, pao_param_initguess_exp
      41             : 
      42             : CONTAINS
      43             : 
      44             : ! **************************************************************************************************
      45             : !> \brief Initialize matrix exponential parametrization
      46             : !> \param pao ...
      47             : !> \param qs_env ...
      48             : ! **************************************************************************************************
      49          24 :    SUBROUTINE pao_param_init_exp(pao, qs_env)
      50             :       TYPE(pao_env_type), POINTER                        :: pao
      51             :       TYPE(qs_environment_type), POINTER                 :: qs_env
      52             : 
      53             :       CHARACTER(len=*), PARAMETER :: routineN = 'pao_param_init_exp'
      54             : 
      55             :       INTEGER                                            :: acol, arow, handle, iatom, N
      56             :       LOGICAL                                            :: found
      57          24 :       REAL(dp), DIMENSION(:), POINTER                    :: H_evals
      58          24 :       REAL(dp), DIMENSION(:, :), POINTER                 :: block_H, block_H0, block_N, block_U0, &
      59          24 :                                                             block_V0, H_evecs
      60             :       TYPE(dbcsr_iterator_type)                          :: iter
      61          24 :       TYPE(dbcsr_p_type), DIMENSION(:), POINTER          :: matrix_s
      62             : 
      63          24 :       CALL timeset(routineN, handle)
      64             : 
      65          24 :       CALL get_qs_env(qs_env, matrix_s=matrix_s)
      66             : 
      67             :       ! allocate matrix_U0
      68             :       CALL dbcsr_create(pao%matrix_U0, &
      69             :                         name="PAO matrix_U0", &
      70             :                         matrix_type="N", &
      71             :                         dist=pao%diag_distribution, &
      72          24 :                         template=matrix_s(1)%matrix)
      73          24 :       CALL dbcsr_reserve_diag_blocks(pao%matrix_U0)
      74             : 
      75             :       ! diagonalize each block of H0 and store eigenvectors in U0
      76             : !$OMP PARALLEL DEFAULT(NONE) SHARED(pao,qs_env) &
      77          24 : !$OMP PRIVATE(iter,arow,acol,iatom,N,found,block_H0,block_V0,block_N,block_H,block_U0,H_evecs,H_evals)
      78             :       CALL dbcsr_iterator_start(iter, pao%matrix_U0)
      79             :       DO WHILE (dbcsr_iterator_blocks_left(iter))
      80             :          CALL dbcsr_iterator_next_block(iter, arow, acol, block_U0)
      81             :          iatom = arow; CPASSERT(arow == acol)
      82             :          CALL dbcsr_get_block_p(matrix=pao%matrix_H0, row=iatom, col=iatom, block=block_H0, found=found)
      83             :          CALL dbcsr_get_block_p(matrix=pao%matrix_N_diag, row=iatom, col=iatom, block=block_N, found=found)
      84             :          CPASSERT(ASSOCIATED(block_H0) .AND. ASSOCIATED(block_N))
      85             :          N = SIZE(block_U0, 1)
      86             : 
      87             :          ALLOCATE (block_V0(N, N))
      88             :          CALL pao_guess_initial_potential(qs_env, iatom, block_V0)
      89             : 
      90             :          ! construct H
      91             :          ALLOCATE (block_H(N, N))
      92             :          block_H = MATMUL(MATMUL(block_N, block_H0 + block_V0), block_N) ! transform into orthonormal basis
      93             : 
      94             :          ! diagonalize H
      95             :          ALLOCATE (H_evecs(N, N), H_evals(N))
      96             :          H_evecs = block_H
      97             :          CALL diamat_all(H_evecs, H_evals)
      98             : 
      99             :          ! use eigenvectors as initial guess
     100             :          block_U0 = H_evecs
     101             : 
     102             :          DEALLOCATE (block_H, H_evecs, H_evals, block_V0)
     103             :       END DO
     104             :       CALL dbcsr_iterator_stop(iter)
     105             : !$OMP END PARALLEL
     106             : 
     107          24 :       IF (pao%precondition) &
     108           0 :          CPABORT("PAO preconditioning not supported for selected parametrization.")
     109             : 
     110          24 :       CALL timestop(handle)
     111          24 :    END SUBROUTINE pao_param_init_exp
     112             : 
     113             : ! **************************************************************************************************
     114             : !> \brief Finalize exponential parametrization
     115             : !> \param pao ...
     116             : ! **************************************************************************************************
     117          24 :    SUBROUTINE pao_param_finalize_exp(pao)
     118             :       TYPE(pao_env_type), POINTER                        :: pao
     119             : 
     120          24 :       CALL dbcsr_release(pao%matrix_U0)
     121             : 
     122          24 :    END SUBROUTINE pao_param_finalize_exp
     123             : 
     124             : ! **************************************************************************************************
     125             : !> \brief Returns the number of parameters for given atomic kind
     126             : !> \param qs_env ...
     127             : !> \param ikind ...
     128             : !> \param nparams ...
     129             : ! **************************************************************************************************
     130         128 :    SUBROUTINE pao_param_count_exp(qs_env, ikind, nparams)
     131             :       TYPE(qs_environment_type), POINTER                 :: qs_env
     132             :       INTEGER, INTENT(IN)                                :: ikind
     133             :       INTEGER, INTENT(OUT)                               :: nparams
     134             : 
     135             :       INTEGER                                            :: cols, pao_basis_size, pri_basis_size, &
     136             :                                                             rows
     137             :       TYPE(gto_basis_set_type), POINTER                  :: basis_set
     138          64 :       TYPE(qs_kind_type), DIMENSION(:), POINTER          :: qs_kind_set
     139             : 
     140          64 :       CALL get_qs_env(qs_env, qs_kind_set=qs_kind_set)
     141             :       CALL get_qs_kind(qs_kind_set(ikind), &
     142             :                        basis_set=basis_set, &
     143          64 :                        pao_basis_size=pao_basis_size)
     144          64 :       pri_basis_size = basis_set%nsgf
     145             : 
     146             :       ! we only consider rotations between occupied and virtuals
     147          64 :       rows = pao_basis_size
     148          64 :       cols = pri_basis_size - pao_basis_size
     149          64 :       nparams = rows*cols
     150             : 
     151          64 :    END SUBROUTINE pao_param_count_exp
     152             : 
     153             : ! **************************************************************************************************
     154             : !> \brief Fills matrix_X with an initial guess
     155             : !> \param pao ...
     156             : ! **************************************************************************************************
     157          14 :    SUBROUTINE pao_param_initguess_exp(pao)
     158             :       TYPE(pao_env_type), POINTER                        :: pao
     159             : 
     160          14 :       CALL dbcsr_set(pao%matrix_X, 0.0_dp) ! actual initial guess is matrix_U0
     161             : 
     162          14 :    END SUBROUTINE pao_param_initguess_exp
     163             : 
     164             : ! **************************************************************************************************
     165             : !> \brief Takes current matrix_X and calculates the matrices A and B.
     166             : !> \param pao ...
     167             : !> \param qs_env ...
     168             : !> \param ls_scf_env ...
     169             : !> \param gradient ...
     170             : ! **************************************************************************************************
     171        2710 :    SUBROUTINE pao_calc_AB_exp(pao, qs_env, ls_scf_env, gradient)
     172             :       TYPE(pao_env_type), POINTER                        :: pao
     173             :       TYPE(qs_environment_type), POINTER                 :: qs_env
     174             :       TYPE(ls_scf_env_type), TARGET                      :: ls_scf_env
     175             :       LOGICAL, INTENT(IN)                                :: gradient
     176             : 
     177             :       CHARACTER(len=*), PARAMETER                        :: routineN = 'pao_calc_AB_exp'
     178             : 
     179             :       INTEGER                                            :: handle
     180        2710 :       TYPE(dbcsr_p_type), DIMENSION(:), POINTER          :: matrix_s
     181             :       TYPE(dbcsr_type)                                   :: matrix_M, matrix_U
     182             : 
     183        2710 :       CALL timeset(routineN, handle)
     184        2710 :       CALL get_qs_env(qs_env, matrix_s=matrix_s)
     185        2710 :       CALL dbcsr_create(matrix_U, matrix_type="N", dist=pao%diag_distribution, template=matrix_s(1)%matrix)
     186        2710 :       CALL dbcsr_reserve_diag_blocks(matrix_U)
     187             : 
     188             :       !TODO: move this condition into pao_calc_U, use matrix_N as template
     189        2710 :       IF (gradient) THEN
     190         488 :          CALL pao_calc_grad_lnv_wrt_U(qs_env, ls_scf_env, matrix_M)
     191         488 :          CALL pao_calc_U_exp(pao, matrix_U, matrix_M, pao%matrix_G)
     192         488 :          CALL dbcsr_release(matrix_M)
     193             :       ELSE
     194        2222 :          CALL pao_calc_U_exp(pao, matrix_U)
     195             :       END IF
     196             : 
     197        2710 :       CALL pao_calc_AB_from_U(pao, qs_env, ls_scf_env, matrix_U)
     198        2710 :       CALL dbcsr_release(matrix_U)
     199        2710 :       CALL timestop(handle)
     200        2710 :    END SUBROUTINE pao_calc_AB_exp
     201             : 
     202             : ! **************************************************************************************************
     203             : !> \brief Calculate new matrix U and optionally its gradient G
     204             : !> \param pao ...
     205             : !> \param matrix_U ...
     206             : !> \param matrix_M ...
     207             : !> \param matrix_G ...
     208             : ! **************************************************************************************************
     209        2710 :    SUBROUTINE pao_calc_U_exp(pao, matrix_U, matrix_M, matrix_G)
     210             :       TYPE(pao_env_type), POINTER                        :: pao
     211             :       TYPE(dbcsr_type)                                   :: matrix_U
     212             :       TYPE(dbcsr_type), OPTIONAL                         :: matrix_M, matrix_G
     213             : 
     214             :       CHARACTER(len=*), PARAMETER                        :: routineN = 'pao_calc_U_exp'
     215             : 
     216             :       COMPLEX(dp)                                        :: denom
     217        2710 :       COMPLEX(dp), DIMENSION(:), POINTER                 :: evals
     218        2710 :       COMPLEX(dp), DIMENSION(:, :), POINTER              :: block_D, evecs
     219             :       INTEGER                                            :: acol, arow, handle, i, iatom, j, k, M, &
     220             :                                                             N, nparams
     221        2710 :       INTEGER, DIMENSION(:), POINTER                     :: blk_sizes_pao, blk_sizes_pri
     222             :       LOGICAL                                            :: found
     223        2710 :       REAL(dp), DIMENSION(:, :), POINTER                 :: block_G, block_G_full, block_M, &
     224        2710 :                                                             block_tmp, block_U, block_U0, block_X, &
     225        2710 :                                                             block_X_full
     226             :       TYPE(dbcsr_iterator_type)                          :: iter
     227             : 
     228        2710 :       CALL timeset(routineN, handle)
     229             : 
     230        2710 :       CALL dbcsr_get_info(pao%matrix_Y, row_blk_size=blk_sizes_pri, col_blk_size=blk_sizes_pao)
     231             : 
     232             : !$OMP PARALLEL DEFAULT(NONE) SHARED(pao,matrix_U,matrix_M,matrix_G,blk_sizes_pri,blk_sizes_pao) &
     233             : !$OMP PRIVATE(iter,arow,acol,iatom,N,M,nparams,i,j,k,found) &
     234             : !$OMP PRIVATE(block_X,block_U,block_U0,block_X_full,evals,evecs) &
     235        2710 : !$OMP PRIVATE(block_M,block_G,block_D,block_tmp,block_G_full,denom)
     236             :       CALL dbcsr_iterator_start(iter, pao%matrix_X)
     237             :       DO WHILE (dbcsr_iterator_blocks_left(iter))
     238             :          CALL dbcsr_iterator_next_block(iter, arow, acol, block_X)
     239             :          iatom = arow; CPASSERT(arow == acol)
     240             :          CALL dbcsr_get_block_p(matrix=matrix_U, row=iatom, col=iatom, block=block_U, found=found)
     241             :          CPASSERT(ASSOCIATED(block_U))
     242             :          CALL dbcsr_get_block_p(matrix=pao%matrix_U0, row=iatom, col=iatom, block=block_U0, found=found)
     243             :          CPASSERT(ASSOCIATED(block_U0))
     244             : 
     245             :          N = blk_sizes_pri(iatom) ! size of primary basis
     246             :          M = blk_sizes_pao(iatom) ! size of pao basis
     247             :          nparams = SIZE(block_X, 1)
     248             : 
     249             :          ! block_X stores only rotations between occupied and virtuals
     250             :          ! hence, we first have to build the full anti-symmetric exponent block
     251             :          ALLOCATE (block_X_full(N, N))
     252             :          block_X_full(:, :) = 0.0_dp
     253             :          DO i = 1, nparams
     254             :             block_X_full(MOD(i - 1, M) + 1, M + (i - 1)/M + 1) = +block_X(i, 1)
     255             :             block_X_full(M + (i - 1)/M + 1, MOD(i - 1, M) + 1) = -block_X(i, 1)
     256             :          END DO
     257             : 
     258             :          ! diagonalize block_X_full
     259             :          ALLOCATE (evals(N), evecs(N, N))
     260             :          CALL diag_antisym(block_X_full, evecs, evals)
     261             : 
     262             :          ! construct rotation matrix
     263             :          block_U(:, :) = 0.0_dp
     264             :          DO k = 1, N
     265             :             DO i = 1, N
     266             :                DO j = 1, N
     267             :                   block_U(i, j) = block_U(i, j) + REAL(EXP(evals(k))*evecs(i, k)*CONJG(evecs(j, k)), dp)
     268             :                END DO
     269             :             END DO
     270             :          END DO
     271             : 
     272             :          block_U = MATMUL(block_U0, block_U) ! prepend initial guess rotation
     273             : 
     274             :          ! TURNING POINT (if calc grad) ------------------------------------------
     275             :          IF (PRESENT(matrix_G)) THEN
     276             :             CPASSERT(PRESENT(matrix_M))
     277             : 
     278             :             CALL dbcsr_get_block_p(matrix=pao%matrix_G, row=iatom, col=iatom, block=block_G, found=found)
     279             :             CPASSERT(ASSOCIATED(block_G))
     280             :             CALL dbcsr_get_block_p(matrix=matrix_M, row=iatom, col=iatom, block=block_M, found=found)
     281             :             ! don't check ASSOCIATED(block_M), it might have been filtered out.
     282             : 
     283             :             ALLOCATE (block_D(N, N), block_tmp(N, N), block_G_full(N, N))
     284             :             DO i = 1, N
     285             :                DO j = 1, N
     286             :                   denom = evals(i) - evals(j)
     287             :                   IF (i == j) THEN
     288             :                      block_D(i, i) = EXP(evals(i)) ! diagonal elements
     289             :                   ELSE IF (ABS(denom) > 1e-10_dp) THEN
     290             :                      block_D(i, j) = (EXP(evals(i)) - EXP(evals(j)))/denom
     291             :                   ELSE
     292             :                      block_D(i, j) = 1.0_dp ! limit according to L'Hospital's rule
     293             :                   END IF
     294             :                END DO
     295             :             END DO
     296             : 
     297             :             IF (ASSOCIATED(block_M)) THEN
     298             :                block_tmp = MATMUL(TRANSPOSE(block_U0), block_M)
     299             :             ELSE
     300             :                block_tmp = 0.0_dp
     301             :             END IF
     302             :             block_G_full = fold_derivatives(block_tmp, block_D, evecs)
     303             : 
     304             :             ! return only gradient for rotations between occupied and virtuals
     305             :             DO i = 1, nparams
     306             :                block_G(i, 1) = 2.0_dp*block_G_full(MOD(i - 1, M) + 1, M + (i - 1)/M + 1)
     307             :             END DO
     308             : 
     309             :             DEALLOCATE (block_D, block_tmp, block_G_full)
     310             :          END IF
     311             : 
     312             :          DEALLOCATE (block_X_full, evals, evecs)
     313             : 
     314             :       END DO
     315             :       CALL dbcsr_iterator_stop(iter)
     316             : !$OMP END PARALLEL
     317             : 
     318        2710 :       CALL timestop(handle)
     319        2710 :    END SUBROUTINE pao_calc_U_exp
     320             : 
     321             : ! **************************************************************************************************
     322             : !> \brief Helper routine, for calculating derivatives
     323             : !> \param M ...
     324             : !> \param D ...
     325             : !> \param R ...
     326             : !> \return ...
     327             : ! **************************************************************************************************
     328         683 :    FUNCTION fold_derivatives(M, D, R) RESULT(G)
     329             :       REAL(dp), DIMENSION(:, :), INTENT(IN)              :: M
     330             :       COMPLEX(dp), DIMENSION(:, :), INTENT(IN)           :: D, R
     331             :       REAL(dp), DIMENSION(SIZE(M, 1), SIZE(M, 1))        :: G
     332             : 
     333         683 :       COMPLEX(dp), DIMENSION(:, :), POINTER              :: F, RF, RM, RMR
     334             :       INTEGER                                            :: n
     335         683 :       REAL(dp), DIMENSION(:, :), POINTER                 :: RFR
     336             : 
     337         683 :       n = SIZE(M, 1)
     338             : 
     339        8879 :       ALLOCATE (RM(n, n), RMR(n, n), F(n, n), RF(n, n), RFR(n, n))
     340             : 
     341      642537 :       RM = MATMUL(TRANSPOSE(CONJG(R)), TRANSPOSE(M))
     342     1133318 :       RMR = MATMUL(RM, R)
     343      101626 :       F = RMR*D !Hadamard product
     344      641854 :       RF = MATMUL(R, F)
     345     1133318 :       RFR = REAL(MATMUL(RF, TRANSPOSE(CONJG(R))), dp)
     346             : 
     347             :       ! gradient dE/dX has to be anti-symmetric
     348       50813 :       G = 0.5_dp*(TRANSPOSE(RFR) - RFR)
     349             : 
     350         683 :       DEALLOCATE (RM, RMR, F, RF, RFR)
     351         683 :    END FUNCTION fold_derivatives
     352             : 
     353         683 : END MODULE pao_param_exp