LCOV - code coverage report
Current view: top level - src/xc - xc_exchange_gga.F (source / functions) Coverage Total Hit
Test: CP2K Regtests (git:123285f) Lines: 31.7 % 300 95
Test Date: 2026-11-04 00:58:17 Functions: 46.2 % 13 6

            Line data    Source code
       1              : !--------------------------------------------------------------------------------------------------!
       2              : !   CP2K: A general program to perform molecular dynamics simulations                              !
       3              : !   Copyright 2000-2026 CP2K developers group <https://cp2k.org>                                   !
       4              : !                                                                                                  !
       5              : !   SPDX-License-Identifier: GPL-2.0-or-later                                                      !
       6              : !--------------------------------------------------------------------------------------------------!
       7              : 
       8              : ! **************************************************************************************************
       9              : !> \brief Calculate several different exchange energy functionals
      10              : !>      with a GGA form
      11              : !> \par History
      12              : !>      JGH (26.02.2003) : OpenMP enabled
      13              : !>      fawzi (04.2004)  : adapted to the new xc interface
      14              : !> \author JGH (27.02.2002)
      15              : ! **************************************************************************************************
      16              : MODULE xc_exchange_gga
      17              : 
      18              :    USE cp_array_utils,                  ONLY: cp_3d_r_cp_type
      19              :    USE cp_log_handling,                 ONLY: cp_to_string
      20              :    USE kinds,                           ONLY: dp
      21              :    USE mathconstants,                   ONLY: pi
      22              :    USE xc_derivative_desc,              ONLY: deriv_norm_drho,&
      23              :                                               deriv_norm_drhoa,&
      24              :                                               deriv_norm_drhob,&
      25              :                                               deriv_rho,&
      26              :                                               deriv_rhoa,&
      27              :                                               deriv_rhob
      28              :    USE xc_derivative_set_types,         ONLY: xc_derivative_set_type,&
      29              :                                               xc_dset_get_derivative
      30              :    USE xc_derivative_types,             ONLY: xc_derivative_get,&
      31              :                                               xc_derivative_type
      32              :    USE xc_functionals_utilities,        ONLY: calc_wave_vector,&
      33              :                                               set_util
      34              :    USE xc_input_constants,              ONLY: xgga_b88,&
      35              :                                               xgga_ev93,&
      36              :                                               xgga_opt,&
      37              :                                               xgga_pbe,&
      38              :                                               xgga_pw86,&
      39              :                                               xgga_pw91,&
      40              :                                               xgga_revpbe
      41              :    USE xc_rho_cflags_types,             ONLY: xc_rho_cflags_type
      42              :    USE xc_rho_set_types,                ONLY: xc_rho_set_get,&
      43              :                                               xc_rho_set_type
      44              : #include "../base/base_uses.f90"
      45              : 
      46              :    IMPLICIT NONE
      47              : 
      48              :    PRIVATE
      49              : 
      50              :    PUBLIC :: xgga_info, xgga_eval
      51              : 
      52              :    REAL(KIND=dp), PARAMETER :: f13 = 1.0_dp/3.0_dp, &
      53              :                                f23 = 2.0_dp*f13, &
      54              :                                f43 = 4.0_dp*f13, &
      55              :                                f53 = 5.0_dp*f13
      56              : 
      57              :    REAL(KIND=dp) :: cx, flda, flsd, sfac, t13
      58              :    REAL(KIND=dp) :: fact, tact
      59              :    REAL(KIND=dp) :: eps_rho
      60              :    CHARACTER(len=*), PARAMETER, PRIVATE :: moduleN = 'xc_exchange_gga'
      61              : 
      62              : CONTAINS
      63              : 
      64              : ! **************************************************************************************************
      65              : !> \brief return various information on the xgga functionals
      66              : !> \param functional integer selecting the xgga functional, it should be one of
      67              : !>        the constants defined in this module: xgga_b88, xgga_pw86,...
      68              : !> \param lsd a logical that specifies if you are asking about the lsd or lda
      69              : !>        version of the functional
      70              : !> \param reference string with the reference of the actual functional
      71              : !> \param shortform string with the shortform of the functional name
      72              : !> \param needs the components needed by this functional are set to
      73              : !>        true (does not set the unneeded components to false)
      74              : !> \param max_deriv ...
      75              : !> \author fawzi
      76              : ! **************************************************************************************************
      77           14 :    SUBROUTINE xgga_info(functional, lsd, reference, shortform, needs, max_deriv)
      78              :       INTEGER, INTENT(in)                                :: functional
      79              :       LOGICAL, INTENT(in)                                :: lsd
      80              :       CHARACTER(LEN=*), INTENT(OUT), OPTIONAL            :: reference, shortform
      81              :       TYPE(xc_rho_cflags_type), INTENT(inout), OPTIONAL  :: needs
      82              :       INTEGER, INTENT(out), OPTIONAL                     :: max_deriv
      83              : 
      84           14 :       IF (PRESENT(reference)) THEN
      85            2 :          SELECT CASE (functional)
      86              :          CASE (xgga_b88)
      87            0 :             reference = "A. Becke, Phys. Rev. A 38, 3098 (1988)"
      88              :          CASE (xgga_pw86)
      89            0 :             reference = "J.P. Perdew and Y. Wang, Phys. Rev. B, 33, 8800 (1986)"
      90              :          CASE (xgga_pw91)
      91            0 :             reference = "J.P. Perdew et al., Phys. Rev. B, 46, 6671 (1992)"
      92              :          CASE (xgga_pbe)
      93            0 :             reference = "J.P. Perdew, K. Burke, M Ernzerhof, Phys. Rev. Lett, 77, 3865 (1996)"
      94              :          CASE (xgga_revpbe)
      95            0 :             reference = "Y. Zhang et al., PRL, 80, 890 (1998) (Revised PBEX)"
      96              :          CASE (xgga_opt)
      97            0 :             reference = "Wee-Meng Hoe, A.J. Cohen, N.C. Handy, CPL, 341, 319 (2001)"
      98              :          CASE (xgga_ev93)
      99            2 :             reference = "E. Engel and S.H. Vosko, Phys. Rev. B, 47, 13164 (1993)"
     100              :          CASE default
     101            2 :             CPABORT("Invalid functional requested ("//cp_to_string(functional)//")")
     102              :          END SELECT
     103            2 :          IF (.NOT. lsd) THEN
     104            2 :             IF (LEN_TRIM(reference) + 6 < LEN(reference)) THEN
     105            2 :                reference(LEN_TRIM(reference):LEN_TRIM(reference) + 6) = ' {LDA}'
     106              :             END IF
     107              :          END IF
     108              :       END IF
     109           14 :       IF (PRESENT(shortform)) THEN
     110            2 :          SELECT CASE (functional)
     111              :          CASE (xgga_b88)
     112            0 :             shortform = "Becke 1988 Exchange Functional"
     113              :          CASE (xgga_pw86)
     114            0 :             shortform = "Perdew-Wang 1986 Functional (exchange energy)"
     115              :          CASE (xgga_pw91)
     116            0 :             shortform = "Perdew-Wang 1991 Functional (exchange energy)"
     117              :          CASE (xgga_pbe)
     118            0 :             shortform = "PBE exchange energy functional"
     119              :          CASE (xgga_revpbe)
     120            0 :             shortform = "Revised PBEX by Zhang et al."
     121              :          CASE (xgga_opt)
     122            0 :             shortform = "OPTX exchange energy functional"
     123              :          CASE (xgga_ev93)
     124            2 :             shortform = "Engel-Vosko exchange energy from virial relation"
     125              :          CASE default
     126            2 :             CPABORT("Invalid functional requested ("//cp_to_string(functional)//")")
     127              :          END SELECT
     128            2 :          IF (.NOT. lsd) THEN
     129            2 :             IF (LEN_TRIM(shortform) + 6 < LEN(shortform)) THEN
     130            2 :                shortform(LEN_TRIM(shortform):LEN_TRIM(shortform) + 6) = ' {LDA}'
     131              :             END IF
     132              :          END IF
     133              :       END IF
     134           14 :       IF (PRESENT(needs)) THEN
     135           12 :          IF (lsd) THEN
     136            0 :             needs%rho_spin = .TRUE.
     137            0 :             needs%rho_spin_1_3 = .TRUE.
     138            0 :             needs%norm_drho_spin = .TRUE.
     139              :          ELSE
     140           12 :             needs%rho = .TRUE.
     141           12 :             needs%rho_1_3 = .TRUE.
     142           12 :             needs%norm_drho = .TRUE.
     143              :          END IF
     144              :       END IF
     145           14 :       IF (PRESENT(max_deriv)) max_deriv = 3
     146              : 
     147           14 :    END SUBROUTINE xgga_info
     148              : 
     149              : ! **************************************************************************************************
     150              : !> \brief evaluates different exchange gga
     151              : !> \param functional integer to select the functional that should be evaluated
     152              : !> \param lsd if the lsd version of the functional should be used
     153              : !> \param rho_set the density where you want to evaluate the functional
     154              : !> \param deriv_set place where to store the functional derivatives (they are
     155              : !>        added to the derivatives)
     156              : !> \param order ...
     157              : !> \author fawzi
     158              : ! **************************************************************************************************
     159            4 :    SUBROUTINE xgga_eval(functional, lsd, rho_set, deriv_set, order)
     160              :       INTEGER, INTENT(in)                                :: functional
     161              :       LOGICAL, INTENT(in)                                :: lsd
     162              :       TYPE(xc_rho_set_type), INTENT(IN)                  :: rho_set
     163              :       TYPE(xc_derivative_set_type), INTENT(IN)           :: deriv_set
     164              :       INTEGER, INTENT(in)                                :: order
     165              : 
     166              :       CHARACTER(len=*), PARAMETER                        :: routineN = 'xgga_eval'
     167              : 
     168              :       INTEGER                                            :: handle, ispin, m, npoints, nspin
     169              :       INTEGER, DIMENSION(2)                              :: norm_drho_spin_name, rho_spin_name
     170              :       INTEGER, DIMENSION(2, 3)                           :: bo
     171              :       REAL(KIND=dp)                                      :: drho_cutoff, rho_cutoff
     172            4 :       REAL(KIND=dp), ALLOCATABLE, DIMENSION(:)           :: s
     173            4 :       REAL(KIND=dp), ALLOCATABLE, DIMENSION(:, :)        :: fs
     174            4 :       REAL(KIND=dp), CONTIGUOUS, DIMENSION(:, :, :), POINTER :: e_0, e_ndrho, e_ndrho_ndrho, &
     175            4 :          e_ndrho_ndrho_ndrho, e_rho, e_rho_ndrho, e_rho_ndrho_ndrho, e_rho_rho, e_rho_rho_ndrho, &
     176            4 :          e_rho_rho_rho
     177           36 :       TYPE(cp_3d_r_cp_type), DIMENSION(2)                :: norm_drho, rho, rho_1_3
     178              :       TYPE(xc_derivative_type), POINTER                  :: deriv
     179              : 
     180            4 :       CALL timeset(routineN, handle)
     181            4 :       NULLIFY (e_0, e_ndrho, e_ndrho_ndrho, e_ndrho_ndrho_ndrho, e_rho_ndrho_ndrho, &
     182            4 :                e_rho_ndrho, e_rho_rho_ndrho, e_rho, e_rho_rho, e_rho_rho_rho)
     183           12 :       DO ispin = 1, 2
     184           12 :          NULLIFY (norm_drho(ispin)%array, rho(ispin)%array, rho_1_3(ispin)%array)
     185              :       END DO
     186              : 
     187            4 :       IF (lsd) THEN
     188              :          CALL xc_rho_set_get(rho_set, rhoa_1_3=rho_1_3(1)%array, &
     189              :                              rhob_1_3=rho_1_3(2)%array, rhoa=rho(1)%array, &
     190              :                              rhob=rho(2)%array, norm_drhoa=norm_drho(1)%array, &
     191              :                              norm_drhob=norm_drho(2)%array, rho_cutoff=rho_cutoff, &
     192            0 :                              drho_cutoff=drho_cutoff, local_bounds=bo)
     193            0 :          nspin = 2
     194            0 :          rho_spin_name = [deriv_rhoa, deriv_rhob]
     195            0 :          norm_drho_spin_name = [deriv_norm_drhoa, deriv_norm_drhob]
     196              :       ELSE
     197              :          CALL xc_rho_set_get(rho_set, rho=rho(1)%array, rho_1_3=rho_1_3(1)%array, &
     198              :                              norm_drho=norm_drho(1)%array, local_bounds=bo, rho_cutoff=rho_cutoff, &
     199            4 :                              drho_cutoff=drho_cutoff)
     200            4 :          nspin = 1
     201            4 :          rho_spin_name = [deriv_rho, deriv_rho]
     202            4 :          norm_drho_spin_name = [deriv_norm_drho, deriv_norm_drho]
     203              :       END IF
     204            4 :       npoints = (bo(2, 1) - bo(1, 1) + 1)*(bo(2, 2) - bo(1, 2) + 1)*(bo(2, 3) - bo(1, 3) + 1)
     205            4 :       m = ABS(order)
     206            4 :       CALL xgga_init(rho_cutoff)
     207              : 
     208           12 :       ALLOCATE (s(npoints))
     209           16 :       ALLOCATE (fs(npoints, m + 1))
     210              : 
     211            8 :       DO ispin = 1, nspin
     212            4 :          IF (lsd) THEN
     213            0 :             fact = flsd
     214            0 :             tact = 1.0_dp
     215            0 :             CALL calc_wave_vector("p", rho(ispin)%array, norm_drho(ispin)%array, s)
     216              :          ELSE
     217            4 :             fact = flda
     218            4 :             tact = t13
     219              :             CALL calc_wave_vector("u", rho(ispin)%array, &
     220            4 :                                   norm_drho(ispin)%array, s)
     221              :          END IF
     222              : 
     223            4 :          SELECT CASE (functional)
     224              :          CASE (xgga_b88)
     225            0 :             CALL efactor_b88(s, fs, m)
     226              :          CASE (xgga_pw86)
     227            0 :             CALL efactor_pw86(s, fs, m)
     228              :          CASE (xgga_pw91)
     229              : 
     230              :             !! omp: note this is handled slightly differently to the
     231              :             !! other cases to prevent sprawling scope declarations
     232              :             !! in efactor_pw91()
     233              : 
     234            0 : !$OMP           PARALLEL DEFAULT (NONE) SHARED(s, fs, m)
     235              :             CALL efactor_pw91(s, fs, m)
     236              : !$OMP           END PARALLEL
     237              : 
     238              :          CASE (xgga_pbe)
     239            0 :             tact = t13
     240            0 :             CALL efactor_pbex(s, fs, m, 1)
     241            0 :             IF (lsd) tact = 1.0_dp
     242              :          CASE (xgga_revpbe)
     243            0 :             tact = t13
     244            0 :             CALL efactor_pbex(s, fs, m, 2)
     245            0 :             IF (lsd) tact = 1.0_dp
     246              :          CASE (xgga_opt)
     247            0 :             CALL efactor_optx(s, fs, m)
     248              :          CASE (xgga_ev93)
     249            4 :             tact = t13
     250            4 :             CALL efactor_ev93(s, fs, m)
     251            4 :             IF (lsd) tact = 1.0_dp
     252              :          CASE DEFAULT
     253            4 :             CPABORT("Unsupported functional")
     254              :          END SELECT
     255              : 
     256              :          deriv => xc_dset_get_derivative(deriv_set, [INTEGER::], &
     257            4 :                                          allocate_deriv=.TRUE.)
     258            4 :          CALL xc_derivative_get(deriv, deriv_data=e_0)
     259              : 
     260              :          CALL x_p_0(rho(ispin)%array, rho_1_3(ispin)%array, fs, e_0, &
     261            4 :                     npoints)
     262            4 :          IF (order >= 1) THEN
     263              :             deriv => xc_dset_get_derivative(deriv_set, [rho_spin_name(ispin)], &
     264            8 :                                             allocate_deriv=.TRUE.)
     265            4 :             CALL xc_derivative_get(deriv, deriv_data=e_rho)
     266              :             deriv => xc_dset_get_derivative(deriv_set, [norm_drho_spin_name(ispin)], &
     267            8 :                                             allocate_deriv=.TRUE.)
     268            4 :             CALL xc_derivative_get(deriv, deriv_data=e_ndrho)
     269              : 
     270              :             CALL x_p_1(rho(ispin)%array, &
     271            4 :                        rho_1_3(ispin)%array, s, fs, e_rho, e_ndrho, npoints)
     272              :          END IF
     273            4 :          IF (order >= 2) THEN
     274              :             deriv => xc_dset_get_derivative(deriv_set, [rho_spin_name(ispin), &
     275            0 :                                                         rho_spin_name(ispin)], allocate_deriv=.TRUE.)
     276            0 :             CALL xc_derivative_get(deriv, deriv_data=e_rho_rho)
     277              :             deriv => xc_dset_get_derivative(deriv_set, [rho_spin_name(ispin), &
     278            0 :                                                         norm_drho_spin_name(ispin)], allocate_deriv=.TRUE.)
     279            0 :             CALL xc_derivative_get(deriv, deriv_data=e_rho_ndrho)
     280              :             deriv => xc_dset_get_derivative(deriv_set, [norm_drho_spin_name(ispin), &
     281            0 :                                                         norm_drho_spin_name(ispin)], allocate_deriv=.TRUE.)
     282            0 :             CALL xc_derivative_get(deriv, deriv_data=e_ndrho_ndrho)
     283              : 
     284              :             CALL x_p_2(rho(ispin)%array, &
     285              :                        rho_1_3(ispin)%array, s, fs, e_rho_rho, e_rho_ndrho, &
     286            0 :                        e_ndrho_ndrho, npoints)
     287              :          END IF
     288            4 :          IF (order >= 3) THEN
     289              :             deriv => xc_dset_get_derivative(deriv_set, [rho_spin_name(ispin), &
     290              :                                                         rho_spin_name(ispin), rho_spin_name(ispin)], &
     291            0 :                                             allocate_deriv=.TRUE.)
     292            0 :             CALL xc_derivative_get(deriv, deriv_data=e_rho_rho_rho)
     293              :             deriv => xc_dset_get_derivative(deriv_set, [rho_spin_name(ispin), &
     294              :                                                         rho_spin_name(ispin), norm_drho_spin_name(ispin)], &
     295            0 :                                             allocate_deriv=.TRUE.)
     296            0 :             CALL xc_derivative_get(deriv, deriv_data=e_rho_rho_ndrho)
     297              :             deriv => xc_dset_get_derivative(deriv_set, [rho_spin_name(ispin), &
     298              :                                                         norm_drho_spin_name(ispin), norm_drho_spin_name(ispin)], &
     299            0 :                                             allocate_deriv=.TRUE.)
     300            0 :             CALL xc_derivative_get(deriv, deriv_data=e_rho_ndrho_ndrho)
     301              :             deriv => xc_dset_get_derivative(deriv_set, [norm_drho_spin_name(ispin), &
     302              :                                                         norm_drho_spin_name(ispin), norm_drho_spin_name(ispin)], &
     303            0 :                                             allocate_deriv=.TRUE.)
     304            0 :             CALL xc_derivative_get(deriv, deriv_data=e_ndrho_ndrho_ndrho)
     305              : 
     306              :             CALL x_p_3(rho(ispin)%array, &
     307              :                        rho_1_3(ispin)%array, s, fs, e_rho_rho_rho, &
     308              :                        e_rho_rho_ndrho, e_rho_ndrho_ndrho, e_ndrho_ndrho_ndrho, &
     309            0 :                        npoints)
     310              :          END IF
     311            8 :          IF (order > 3) THEN
     312            0 :             CPABORT("derivatives bigger than 3 not implemented")
     313              :          END IF
     314              :       END DO
     315              : 
     316            4 :       DEALLOCATE (s)
     317            4 :       DEALLOCATE (fs)
     318              : 
     319            4 :       CALL timestop(handle)
     320           12 :    END SUBROUTINE xgga_eval
     321              : 
     322              : ! **************************************************************************************************
     323              : !> \brief ...
     324              : !> \param cutoff ...
     325              : ! **************************************************************************************************
     326            4 :    SUBROUTINE xgga_init(cutoff)
     327              : 
     328              :       REAL(KIND=dp), INTENT(IN)                          :: cutoff
     329              : 
     330            4 :       eps_rho = cutoff
     331            4 :       CALL set_util(cutoff)
     332              : 
     333            4 :       cx = -0.75_dp*(3.0_dp/pi)**f13
     334            4 :       t13 = 2.0_dp**f13
     335            4 :       flda = cx
     336            4 :       flsd = cx*t13
     337              : 
     338            4 :       sfac = 1.0_dp/(2.0_dp*(3.0_dp*pi*pi)**f13)
     339              : 
     340            4 :    END SUBROUTINE xgga_init
     341              : 
     342              : ! **************************************************************************************************
     343              : !> \brief ...
     344              : !> \param rho ...
     345              : !> \param r13 ...
     346              : !> \param fs ...
     347              : !> \param e_0 ...
     348              : !> \param npoints ...
     349              : ! **************************************************************************************************
     350            4 :    SUBROUTINE x_p_0(rho, r13, fs, e_0, npoints)
     351              : 
     352              :       REAL(KIND=dp), DIMENSION(*), INTENT(IN)            :: rho, r13
     353              :       REAL(KIND=dp), DIMENSION(:, :), INTENT(IN)         :: fs
     354              :       REAL(KIND=dp), DIMENSION(*), INTENT(INOUT)         :: e_0
     355              :       INTEGER, INTENT(in)                                :: npoints
     356              : 
     357              :       INTEGER                                            :: ip
     358              : 
     359              : !$OMP     PARALLEL DO DEFAULT (NONE) &
     360              : !$OMP                 SHARED (npoints, rho, eps_rho, fact, r13, fs, e_0) &
     361            4 : !$OMP                 PRIVATE(ip)
     362              : 
     363              :       DO ip = 1, npoints
     364              : 
     365              :          IF (rho(ip) > eps_rho) THEN
     366              :             e_0(ip) = e_0(ip) + fact*r13(ip)*rho(ip)*fs(ip, 1)
     367              :          END IF
     368              : 
     369              :       END DO
     370              : 
     371              : !$OMP     END PARALLEL DO
     372              : 
     373            4 :    END SUBROUTINE x_p_0
     374              : 
     375              : ! **************************************************************************************************
     376              : !> \brief ...
     377              : !> \param rho ...
     378              : !> \param r13 ...
     379              : !> \param s ...
     380              : !> \param fs ...
     381              : !> \param e_rho ...
     382              : !> \param e_ndrho ...
     383              : !> \param npoints ...
     384              : ! **************************************************************************************************
     385            4 :    SUBROUTINE x_p_1(rho, r13, s, fs, e_rho, e_ndrho, npoints)
     386              : 
     387              :       REAL(KIND=dp), DIMENSION(*), INTENT(IN)            :: rho, r13, s
     388              :       REAL(KIND=dp), DIMENSION(:, :), INTENT(IN)         :: fs
     389              :       REAL(KIND=dp), DIMENSION(*), INTENT(INOUT)         :: e_rho, e_ndrho
     390              :       INTEGER, INTENT(in)                                :: npoints
     391              : 
     392              :       INTEGER                                            :: ip
     393              :       REAL(KIND=dp)                                      :: a0, a1, sx, sy
     394              : 
     395              : !$OMP     PARALLEL DO DEFAULT(NONE) &
     396              : !$OMP                 SHARED(npoints, rho, eps_rho, fact, r13, tact, fs) &
     397              : !$OMP                 SHARED(e_rho, e_ndrho, sfac, s) &
     398            4 : !$OMP                 PRIVATE(ip,a0,a1,sx,sy)
     399              : 
     400              :       DO ip = 1, npoints
     401              : 
     402              :          IF (rho(ip) > eps_rho) THEN
     403              : 
     404              :             a0 = fact*r13(ip)*rho(ip)
     405              :             a1 = f43*fact*r13(ip)
     406              :             sx = -f43*s(ip)/rho(ip)
     407              :             sy = sfac*tact/(r13(ip)*rho(ip))
     408              :             e_rho(ip) = e_rho(ip) + a1*fs(ip, 1) + a0*fs(ip, 2)*sx
     409              :             e_ndrho(ip) = e_ndrho(ip) + a0*fs(ip, 2)*sy
     410              : 
     411              :          END IF
     412              : 
     413              :       END DO
     414              : 
     415              : !$OMP     END PARALLEL DO
     416              : 
     417            4 :    END SUBROUTINE x_p_1
     418              : 
     419              : ! **************************************************************************************************
     420              : !> \brief ...
     421              : !> \param rho ...
     422              : !> \param r13 ...
     423              : !> \param s ...
     424              : !> \param fs ...
     425              : !> \param e_rho_rho ...
     426              : !> \param e_rho_ndrho ...
     427              : !> \param e_ndrho_ndrho ...
     428              : !> \param npoints ...
     429              : ! **************************************************************************************************
     430            0 :    SUBROUTINE x_p_2(rho, r13, s, fs, e_rho_rho, e_rho_ndrho, &
     431              :                     e_ndrho_ndrho, npoints)
     432              : 
     433              :       REAL(KIND=dp), DIMENSION(*), INTENT(IN)            :: rho, r13, s
     434              :       REAL(KIND=dp), DIMENSION(:, :), INTENT(IN)         :: fs
     435              :       REAL(KIND=dp), DIMENSION(*), INTENT(INOUT)         :: e_rho_rho, e_rho_ndrho, e_ndrho_ndrho
     436              :       INTEGER, INTENT(in)                                :: npoints
     437              : 
     438              :       INTEGER                                            :: ip
     439              :       REAL(KIND=dp)                                      :: a0, a1, a2, sx, sxx, sxy, sy
     440              : 
     441              : !$OMP     PARALLEL DO DEFAULT(NONE) &
     442              : !$OMP                 SHARED(npoints, rho, eps_rho, r13, fact, e_rho_rho) &
     443              : !$OMP                 SHARED(e_rho_ndrho, e_ndrho_ndrho, fs, sfac, tact, s) &
     444            0 : !$OMP                 PRIVATE(ip,a0,a1,a2,sx,sy,sxx,sxy)
     445              : 
     446              :       DO ip = 1, npoints
     447              : 
     448              :          IF (rho(ip) > eps_rho) THEN
     449              : 
     450              :             a0 = fact*r13(ip)*rho(ip)
     451              :             a1 = f43*fact*r13(ip)
     452              :             a2 = f13*f43*fact/(r13(ip)*r13(ip))
     453              :             sx = -f43*s(ip)/rho(ip)
     454              :             sy = sfac*tact/(r13(ip)*rho(ip))
     455              :             sxx = 28.0_dp/9.0_dp*s(ip)/(rho(ip)*rho(ip))
     456              :             sxy = -f43*sfac*tact/(r13(ip)*rho(ip)*rho(ip))
     457              :             e_rho_rho(ip) = e_rho_rho(ip) + a2*fs(ip, 1) + 2.0_dp*a1*fs(ip, 2)*sx + &
     458              :                             a0*fs(ip, 3)*sx*sx + a0*fs(ip, 2)*sxx
     459              :             e_rho_ndrho(ip) = e_rho_ndrho(ip) &
     460              :                               + a1*fs(ip, 2)*sy + a0*fs(ip, 3)*sx*sy + a0*fs(ip, 2)*sxy
     461              :             e_ndrho_ndrho(ip) = e_ndrho_ndrho(ip) + a0*fs(ip, 3)*sy*sy
     462              : 
     463              :          END IF
     464              : 
     465              :       END DO
     466              : 
     467              : !$OMP     END PARALLEL DO
     468              : 
     469            0 :    END SUBROUTINE x_p_2
     470              : 
     471              : ! **************************************************************************************************
     472              : !> \brief ...
     473              : !> \param rho ...
     474              : !> \param r13 ...
     475              : !> \param s ...
     476              : !> \param fs ...
     477              : !> \param e_rho_rho_rho ...
     478              : !> \param e_rho_rho_ndrho ...
     479              : !> \param e_rho_ndrho_ndrho ...
     480              : !> \param e_ndrho_ndrho_ndrho ...
     481              : !> \param npoints ...
     482              : ! **************************************************************************************************
     483            0 :    SUBROUTINE x_p_3(rho, r13, s, fs, e_rho_rho_rho, e_rho_rho_ndrho, &
     484              :                     e_rho_ndrho_ndrho, e_ndrho_ndrho_ndrho, npoints)
     485              : 
     486              :       REAL(KIND=dp), DIMENSION(*), INTENT(IN)            :: rho, r13, s
     487              :       REAL(KIND=dp), DIMENSION(:, :), INTENT(IN)         :: fs
     488              :       REAL(KIND=dp), DIMENSION(*), INTENT(INOUT)         :: e_rho_rho_rho, e_rho_rho_ndrho, &
     489              :                                                             e_rho_ndrho_ndrho, e_ndrho_ndrho_ndrho
     490              :       INTEGER, INTENT(in)                                :: npoints
     491              : 
     492              :       INTEGER                                            :: ip
     493              :       REAL(KIND=dp)                                      :: a0, a1, a2, a3, sx, sxx, sxxx, sxxy, &
     494              :                                                             sxy, sy
     495              : 
     496              : !$OMP     PARALLEL DO DEFAULT (NONE) &
     497              : !$OMP                 SHARED(npoints, rho, eps_rho, r13, fact, fs) &
     498              : !$OMP                 SHARED(e_rho_rho_rho, e_rho_rho_ndrho) &
     499              : !$OMP                 SHARED(e_rho_ndrho_ndrho, e_ndrho_ndrho_ndrho) &
     500              : !$OMP                 SHARED(sfac, tact, s) &
     501            0 : !$OMP                 PRIVATE(ip,a0,a1,a2,a3,sx,sy,sxx,sxy,sxxx,sxxy)
     502              : 
     503              :       DO ip = 1, npoints
     504              : 
     505              :          IF (rho(ip) > eps_rho) THEN
     506              : 
     507              :             a0 = fact*r13(ip)*rho(ip)
     508              :             a1 = f43*fact*r13(ip)
     509              :             a2 = f13*f43*fact/(r13(ip)*r13(ip))
     510              :             a3 = -f23*f13*f43*fact/(r13(ip)*r13(ip)*rho(ip))
     511              :             sx = -f43*s(ip)/rho(ip)
     512              :             sy = sfac*tact/(r13(ip)*rho(ip))
     513              :             sxx = 28.0_dp/9.0_dp*s(ip)/(rho(ip)*rho(ip))
     514              :             sxy = -f43*sfac*tact/(r13(ip)*rho(ip)*rho(ip))
     515              :             sxxx = -280.0_dp/27.0_dp*s(ip)/(rho(ip)*rho(ip)*rho(ip))
     516              :             sxxy = 28.0_dp/9.0_dp*sfac*tact/(r13(ip)*rho(ip)*rho(ip)*rho(ip))
     517              :             e_rho_rho_rho(ip) = e_rho_rho_rho(ip) &
     518              :                                 + a3*fs(ip, 1) + 3.0_dp*a2*fs(ip, 2)*sx + &
     519              :                                 3.0_dp*a1*fs(ip, 3)*sx*sx + 3.0_dp*a1*fs(ip, 2)*sxx + &
     520              :                                 a0*fs(ip, 4)*sx*sx*sx + 3.0_dp*a0*fs(ip, 3)*sx*sxx + &
     521              :                                 a0*fs(ip, 2)*sxxx
     522              :             e_rho_rho_ndrho(ip) = e_rho_rho_ndrho(ip) &
     523              :                                   + a2*fs(ip, 2)*sy + 2.0_dp*a1*fs(ip, 3)*sx*sy + &
     524              :                                   2.0_dp*a1*fs(ip, 2)*sxy + a0*fs(ip, 4)*sx*sx*sy + &
     525              :                                   2.0_dp*a0*fs(ip, 3)*sx*sxy + a0*fs(ip, 3)*sxx*sy + &
     526              :                                   a0*fs(ip, 2)*sxxy
     527              :             e_rho_ndrho_ndrho(ip) = e_rho_ndrho_ndrho(ip) &
     528              :                                     + a1*fs(ip, 3)*sy*sy + a0*fs(ip, 4)*sx*sy*sy + &
     529              :                                     2.0_dp*a0*fs(ip, 3)*sxy*sy
     530              :             e_ndrho_ndrho_ndrho(ip) = e_ndrho_ndrho_ndrho(ip) &
     531              :                                       + a0*fs(ip, 4)*sy*sy*sy
     532              : 
     533              :          END IF
     534              : 
     535              :       END DO
     536              : 
     537              : !$OMP     END PARALLEL DO
     538              : 
     539            0 :    END SUBROUTINE x_p_3
     540              : 
     541              : ! Enhancement Factors
     542              : ! **************************************************************************************************
     543              : !> \brief ...
     544              : !> \param s ...
     545              : !> \param fs ...
     546              : !> \param m ...
     547              : ! **************************************************************************************************
     548            0 :    SUBROUTINE efactor_b88(s, fs, m)
     549              :       REAL(KIND=dp), DIMENSION(:), INTENT(IN)            :: s
     550              :       REAL(KIND=dp), DIMENSION(:, :), INTENT(INOUT)      :: fs
     551              :       INTEGER, INTENT(IN)                                :: m
     552              : 
     553              :       INTEGER                                            :: ip
     554              :       REAL(KIND=dp) :: as, asp, beta, bs, f0, p, q, sas, sbs, sbs3, t1, t10, t13, t15, t16, t19, &
     555              :          t2, t22, t24, t25, t32, t34, t36, t39, t4, t40, t41, t44, t48, t49, t5, t6, t65, t8, t87, &
     556              :          t9, x, ys
     557              : 
     558            0 :       beta = 0.0042_dp
     559            0 :       f0 = 1.0_dp/sfac
     560            0 :       p = -beta/flsd
     561            0 :       q = 6.0_dp*beta
     562              : 
     563              : !$OMP     PARALLEL DO DEFAULT(NONE) &
     564              : !$OMP                 SHARED(s,fs,m,beta,f0,p,q) &
     565              : !$OMP                 PRIVATE(ip,x,bs,sbs,as,sas,ys,asp,sbs3) &
     566              : !$OMP                 PRIVATE(t1,t2,t4,t5,t6,t8,t9,t10,t13,t15,t16,t19,t22) &
     567              : !$OMP                 PRIVATE(t24,t25,t32,t34) &
     568            0 : !$OMP                 PRIVATE(t36,t39,t40,t41,t44,t48,t49,t65,t87)
     569              : 
     570              :       DO ip = 1, SIZE(s)
     571              :          x = s(ip)*f0
     572              :          bs = beta*x
     573              :          sbs = SQRT(x*x + 1.0_dp)
     574              :          as = LOG(x + sbs)
     575              :          sas = x*as
     576              :          ys = 1.0_dp/(1.0_dp + q*sas)
     577              :          SELECT CASE (m)
     578              :          CASE (0)
     579              :             fs(ip, 1) = 1.0_dp + p*x*x*ys
     580              :          CASE (1)
     581              :             asp = as + x/sbs
     582              :             fs(ip, 1) = 1.0_dp + p*x*x*ys
     583              :             fs(ip, 2) = (2.0_dp*p*x*ys - p*q*x*x*asp*ys*ys)*f0
     584              :          CASE (2)
     585              :             asp = as + x/sbs
     586              :             sbs3 = 1.0_dp/(sbs*sbs*sbs)
     587              :             fs(ip, 1) = 1.0_dp + p*x*x*ys
     588              :             fs(ip, 2) = (2.0_dp*p*x*ys - p*q*x*x*asp*ys*ys)*f0
     589              :             fs(ip, 3) = -f0*f0*p*ys**3*sbs3*(q*x*x*x*x*(q*sas + 5.0_dp &
     590              :                                                         - 2.0_dp*q*sbs) + 2.0_dp*(x*x*(q*q*sas &
     591              :                                                                                        + 3.0_dp*q - sbs) - sbs))
     592              :          CASE (3)
     593              :             asp = as + x/sbs
     594              :             sbs3 = 1.0_dp/(sbs*sbs*sbs)
     595              :             fs(ip, 1) = 1.0_dp + p*x*x*ys
     596              :             fs(ip, 2) = (2.0_dp*p*x*ys - p*q*x*x*asp*ys*ys)*f0
     597              :             fs(ip, 3) = -f0*f0*p*ys**3*sbs3*(q*x*x*x*x*(q*sas + 5.0_dp &
     598              :                                                         - 2.0_dp*q*sbs) + 2.0_dp*(x*x*(q*q*sas &
     599              :                                                                                        + 3.0_dp*q - sbs) - sbs))
     600              :             t1 = q*x
     601              :             t2 = x**2
     602              :             t4 = SQRT(1 + t2)
     603              :             t5 = x + t4
     604              :             t6 = LOG(t5)
     605              :             t8 = 1 + t1*t6
     606              :             t9 = t8**2
     607              :             t10 = 1/t9
     608              :             t13 = 1/t4
     609              :             t15 = 1 + t13*x
     610              :             t16 = 1/t5
     611              :             t19 = q*t6 + t1*t15*t16
     612              :             t22 = p*x
     613              :             t24 = 1/t9/t8
     614              :             t25 = t19**2
     615              :             t32 = t4**2
     616              :             t34 = 1/t32/t4
     617              :             t36 = -t34*t2 + t13
     618              :             t39 = t15**2
     619              :             t40 = t5**2
     620              :             t41 = 1/t40
     621              :             t44 = 2*q*t15*t16 + t1*t36*t16 - t1*t39*t41
     622              :             t48 = p*t2
     623              :             t49 = t9**2
     624              :             t65 = t32**2
     625              :             t87 = -6*p*t10*t19 + 12*t22*t24*t25 - 6*t22*t10*t44 - 6*t48/t49*t25*t19 + &
     626              :                   6*t48*t24*t19*t44 - t48*t10*(3*q*t36*t16 - 3*q*t39*t41 + 3*t1*(1/t65/t4* &
     627              :                                                                          t2*x - t34*x)*t16 - 3*t1*t36*t41*t15 + 2*t1*t39*t15/t40/t5)
     628              : 
     629              :             fs(ip, 4) = t87
     630              :             fs(ip, 4) = f0*f0*f0*fs(ip, 4)
     631              : 
     632              :          CASE DEFAULT
     633              :             CPABORT("Illegal order")
     634              :          END SELECT
     635              :       END DO
     636              : 
     637              : !$OMP     END PARALLEL DO
     638              : 
     639            0 :    END SUBROUTINE efactor_b88
     640              : ! **************************************************************************************************
     641              : !> \brief ...
     642              : !> \param s ...
     643              : !> \param fs ...
     644              : !> \param m ...
     645              : ! **************************************************************************************************
     646            0 :    SUBROUTINE efactor_pw86(s, fs, m)
     647              :       REAL(KIND=dp), DIMENSION(:), INTENT(IN)            :: s
     648              :       REAL(KIND=dp), DIMENSION(:, :), INTENT(INOUT)      :: fs
     649              :       INTEGER, INTENT(IN)                                :: m
     650              : 
     651              :       INTEGER                                            :: ip
     652              :       REAL(KIND=dp)                                      :: f15, p0, p1, p15, s2, s4, s6, t1, t10, &
     653              :                                                             t12, t13, t14, t19, t2, t25, t3, t8, t9
     654              : 
     655            0 :       t1 = 1.296_dp
     656            0 :       t2 = 14.0_dp
     657            0 :       t3 = 0.2_dp
     658            0 :       f15 = 1.0_dp/15.0_dp
     659              : 
     660              : !$OMP     PARALLEL DO DEFAULT(NONE) &
     661              : !$OMP                 SHARED(s, fs, m, t1, t2, t3, f15) &
     662              : !$OMP                 PRIVATE(ip,s2,s4,s6,p0,p1,p15)&
     663            0 : !$OMP                 PRIVATE(t8, t9, t10, t12, t13, t14, t19, t25)
     664              : 
     665              :       DO ip = 1, SIZE(s)
     666              :          s2 = s(ip)*s(ip)
     667              :          s4 = s2*s2
     668              :          s6 = s2*s4
     669              :          SELECT CASE (m)
     670              :          CASE (0)
     671              :             p0 = 1.0_dp + t1*s2 + t2*s4 + t3*s6
     672              :             fs(ip, 1) = p0**f15
     673              :          CASE (1)
     674              :             p0 = 1.0_dp + t1*s2 + t2*s4 + t3*s6
     675              :             p1 = s(ip)*(2.0_dp*t1 + 4.0_dp*t2*s2 + 6.0_dp*t3*s4)
     676              :             p15 = p0**f15
     677              :             fs(ip, 1) = p15
     678              :             fs(ip, 2) = f15*p1*p15/p0
     679              :          CASE (2)
     680              :             p0 = 1.0_dp + t1*s2 + t2*s4 + t3*s6
     681              :             p1 = s(ip)*(2.0_dp*t1 + 4.0_dp*t2*s2 + 6.0_dp*t3*s4)
     682              :             p15 = p0**f15
     683              :             fs(ip, 1) = p15
     684              :             fs(ip, 2) = f15*p1*p15/p0
     685              :             t9 = p15**2; t10 = t9**2; t12 = t10**2; t13 = t12*t10*t9
     686              :             t25 = p1*p1
     687              :             fs(ip, 3) = -14.0_dp/225.0_dp/t13/p0*t25 + &
     688              :                         1.0_dp/t13*(2.0_dp*t1 + 12*t2*s2 + 30.0_dp*t3*s4)/15.0_dp
     689              :          CASE (3)
     690              :             p0 = 1.0_dp + t1*s2 + t2*s4 + t3*s6
     691              :             p1 = s(ip)*(2.0_dp*t1 + 4.0_dp*t2*s2 + 6.0_dp*t3*s4)
     692              :             p15 = p0**f15
     693              :             fs(ip, 1) = p15
     694              :             fs(ip, 2) = f15*p1*p15/p0
     695              :             t9 = p15**2; t10 = t9**2; t12 = t10**2; t13 = t12*t10*t9
     696              :             t25 = p1*p1
     697              :             fs(ip, 3) = -14.0_dp/225.0_dp/t13/p0*t25 + &
     698              :                         1.0_dp/t13*(2.0_dp*t1 + 12*t2*s2 + 30.0_dp*t3*s4)/15.0_dp
     699              :             t8 = p0**2; t9 = p0**f15; t14 = p0/t9; t19 = s2*s(ip)
     700              :             fs(ip, 4) = 406.0_dp/3375.0_dp/t14/t8*p1*p1*p1 - 14.0_dp/ &
     701              :                         75.0_dp/t14/p0*p1*(2*t1 + 12*t2*s2 + 30*t3*s4) + &
     702              :                         1/t14*(24*t2*s(ip) + 120*t3*t19)*f15
     703              :          CASE DEFAULT
     704              :             CPABORT("Illegal order")
     705              :          END SELECT
     706              :       END DO
     707              : 
     708              : !$OMP     END PARALLEL DO
     709              : 
     710            0 :    END SUBROUTINE efactor_pw86
     711              : ! **************************************************************************************************
     712              : !> \brief ...
     713              : !> \param s ...
     714              : !> \param fs ...
     715              : !> \param m ...
     716              : ! **************************************************************************************************
     717            4 :    SUBROUTINE efactor_ev93(s, fs, m)
     718              :       REAL(KIND=dp), DIMENSION(:), INTENT(IN)            :: s
     719              :       REAL(KIND=dp), DIMENSION(:, :), INTENT(INOUT)      :: fs
     720              :       INTEGER, INTENT(IN)                                :: m
     721              : 
     722              :       INTEGER                                            :: ip
     723              :       REAL(KIND=dp)                                      :: a1, a2, a3, b1, b2, b3, d0, d1, d2, d3, &
     724              :                                                             f0, f1, f2, n0, n1, n2, n3, s2, s4, &
     725              :                                                             s6, scale_s, ss
     726              : 
     727            4 :       a1 = 1.647127_dp
     728            4 :       a2 = 0.980118_dp
     729            4 :       a3 = 0.017399_dp
     730            4 :       b1 = 1.523671_dp
     731            4 :       b2 = 0.367229_dp
     732            4 :       b3 = 0.011282_dp
     733            4 :       scale_s = 1._dp/tact
     734              : 
     735              : !$OMP     PARALLEL DO DEFAULT(NONE) &
     736              : !$OMP                 SHARED(s, fs, m, a1, a2, a3, b1, b2, b3, scale_s) &
     737              : !$OMP                 PRIVATE(ip,ss,s2,s4,s6) &
     738            4 : !$OMP                 PRIVATE(n0,n1,n2,n3,d0,d1,d2,d3,f0,f1,f2)
     739              : 
     740              :       DO ip = 1, SIZE(s)
     741              : !     ss = s(ip)
     742              : !
     743              :          ss = scale_s*s(ip)
     744              :          s2 = ss*ss
     745              :          s4 = s2*s2
     746              :          s6 = s2*s4
     747              :          SELECT CASE (m)
     748              :          CASE (0)
     749              :             n0 = 1._dp + a1*s2 + a2*s4 + a3*s6
     750              :             d0 = 1._dp + b1*s2 + b2*s4 + b3*s6
     751              :             fs(ip, 1) = n0/d0
     752              :          CASE (1)
     753              :             n0 = 1._dp + a1*s2 + a2*s4 + a3*s6
     754              :             d0 = 1._dp + b1*s2 + b2*s4 + b3*s6
     755              :             n1 = ss*(2._dp*a1 + 4._dp*a2*s2 + 6._dp*a3*s4)
     756              :             d1 = ss*(2._dp*b1 + 4._dp*b2*s2 + 6._dp*b3*s4)
     757              :             f0 = n0/d0
     758              :             fs(ip, 1) = f0
     759              :             fs(ip, 2) = (n1 - f0*d1)/d0*scale_s
     760              :          CASE (2)
     761              :             n0 = 1._dp + a1*s2 + a2*s4 + a3*s6
     762              :             d0 = 1._dp + b1*s2 + b2*s4 + b3*s6
     763              :             n1 = ss*(2._dp*a1 + 4._dp*a2*s2 + 6._dp*a3*s4)
     764              :             d1 = ss*(2._dp*b1 + 4._dp*b2*s2 + 6._dp*b3*s4)
     765              :             n2 = 2._dp*a1 + 12._dp*a2*s2 + 30._dp*a3*s4
     766              :             d2 = 2._dp*b1 + 12._dp*b2*s2 + 30._dp*b3*s4
     767              :             f0 = n0/d0
     768              :             f1 = (n1 - f0*d1)/d0
     769              :             fs(ip, 1) = f0
     770              :             fs(ip, 2) = f1*scale_s
     771              :             fs(ip, 3) = (n2 - f0*d2 - 2._dp*f1*d1)/d0*scale_s*scale_s
     772              :          CASE (3)
     773              :             n0 = 1._dp + a1*s2 + a2*s4 + a3*s6
     774              :             d0 = 1._dp + b1*s2 + b2*s4 + b3*s6
     775              :             n1 = ss*(2._dp*a1 + 4._dp*a2*s2 + 6._dp*a3*s4)
     776              :             d1 = ss*(2._dp*b1 + 4._dp*b2*s2 + 6._dp*b3*s4)
     777              :             n2 = 2._dp*a1 + 12._dp*a2*s2 + 30._dp*a3*s4
     778              :             d2 = 2._dp*b1 + 12._dp*b2*s2 + 30._dp*b3*s4
     779              :             n3 = ss*(24._dp*a2 + 120._dp*a3*s2)
     780              :             d3 = ss*(24._dp*b2 + 120._dp*b3*s2)
     781              :             f0 = n0/d0
     782              :             f1 = (n1 - f0*d1)/d0
     783              :             f2 = (n2 - f0*d2 - 2._dp*f1*d1)/d0
     784              :             fs(ip, 1) = f0
     785              :             fs(ip, 2) = f1*scale_s
     786              :             fs(ip, 3) = f2*scale_s*scale_s
     787              :             fs(ip, 4) = (n3 - f0*d3 - 3._dp*f2*d1 - 3._dp*f1*d2)/d0*scale_s*scale_s*scale_s
     788              :          CASE DEFAULT
     789              :             CPABORT("Illegal order")
     790              :          END SELECT
     791              :       END DO
     792              : 
     793              : !$OMP     END PARALLEL DO
     794              : 
     795            4 :    END SUBROUTINE efactor_ev93
     796              : ! **************************************************************************************************
     797              : !> \brief ...
     798              : !> \param s ...
     799              : !> \param fs ...
     800              : !> \param m ...
     801              : ! **************************************************************************************************
     802            0 :    SUBROUTINE efactor_optx(s, fs, m)
     803              :       REAL(KIND=dp), DIMENSION(:), INTENT(IN)            :: s
     804              :       REAL(KIND=dp), DIMENSION(:, :), INTENT(OUT)        :: fs
     805              :       INTEGER, INTENT(IN)                                :: m
     806              : 
     807              :       REAL(KIND=dp), PARAMETER                           :: a1 = 1.05151_dp, a2 = 1.43169_dp, &
     808              :                                                             gamma_bo = 0.006_dp
     809              : 
     810              :       INTEGER                                            :: ip
     811              :       REAL(KIND=dp)                                      :: a, b, f0, x, y
     812              : 
     813            0 :       f0 = 1.0_dp/sfac
     814            0 :       b = -a2/flsd
     815              : 
     816              : !$OMP     PARALLEL DO DEFAULT(NONE) &
     817              : !$OMP                 SHARED(s, fs, m, f0, b) &
     818            0 : !$OMP                 PRIVATE(ip,x,A,y)
     819              : 
     820              :       DO ip = 1, SIZE(s)
     821              :          x = s(ip)*f0
     822              :          a = gamma_bo*x*x
     823              :          y = 1.0_dp/(1.0_dp + a)
     824              :          SELECT CASE (m)
     825              :          CASE (0)
     826              :             fs(ip, 1) = a1 + b*a*a*y*y
     827              :          CASE (1)
     828              :             fs(ip, 1) = a1 + b*a*a*y*y
     829              :             fs(ip, 2) = 4.0_dp*b*f0*a*gamma_bo*x*y*y*y
     830              :          CASE (2)
     831              :             fs(ip, 1) = a1 + b*a*a*y*y
     832              :             fs(ip, 2) = 4.0_dp*b*f0*a*gamma_bo*x*y*y*y
     833              :             fs(ip, 3) = -12.0_dp*b*f0*f0*gamma_bo*a*(a - 1.0_dp)*y*y*y*y
     834              :          CASE (3)
     835              :             fs(ip, 1) = a1 + b*a*a*y*y
     836              :             fs(ip, 2) = 4.0_dp*b*f0*a*gamma_bo*x*y*y*y
     837              :             fs(ip, 3) = -12.0_dp*b*f0*f0*gamma_bo*a*(a - 1.0_dp)*y*y*y*y
     838              :             fs(ip, 4) = 24.0_dp*b*f0*f0*f0*gamma_bo*gamma_bo*x* &
     839              :                         (1.0_dp - 5.0_dp*a + 2.0_dp*a*a)*y*y*y*y*y
     840              :          CASE DEFAULT
     841              :             CPABORT("Illegal order")
     842              :          END SELECT
     843              :       END DO
     844              : 
     845              : !$OMP     END PARALLEL DO
     846              : 
     847            0 :    END SUBROUTINE efactor_optx
     848              : 
     849              : ! **************************************************************************************************
     850              : !> \brief ...
     851              : !> \param s ...
     852              : !> \param fs ...
     853              : !> \param m ...
     854              : ! **************************************************************************************************
     855            0 :    SUBROUTINE efactor_pw91(s, fs, m)
     856              :       REAL(KIND=dp), DIMENSION(:), INTENT(IN)            :: s
     857              :       REAL(KIND=dp), DIMENSION(:, :), INTENT(OUT)        :: fs
     858              :       INTEGER, INTENT(IN)                                :: m
     859              : 
     860              :       INTEGER                                            :: ip
     861              :       REAL(dp) :: t1, t10, t101, t106, t109, t111, t113, t119, t12, t123, t124, t13, t14, t15, &
     862              :          t16, t17, t18, t19, t2, t20, t21, t22, t23, t25, t26, t27, t28, t29, t3, t30, t31, t33, &
     863              :          t35, t37, t38, t39, t4, t40, t44, t47, t48, t5, t50, t51, t53, t55, t56, t57, t58, t59, &
     864              :          t6, t60, t64, t65, t69, t7, t70, t71, t73, t77, t78, t8, t80, t82, t9, t90, t93, t94, &
     865              :          t96, t98
     866              :       REAL(KIND=dp)                                      :: a1, a2, a3, a4, a5, b, o, x
     867              : 
     868            0 :       o = 1.0_dp
     869            0 :       a1 = 0.19645_dp
     870            0 :       a2 = 0.2743_dp
     871            0 :       a3 = 0.1508_dp
     872            0 :       a4 = 100.0_dp
     873            0 :       b = 0.8145161_dp
     874            0 :       a5 = 0.004_dp
     875            0 :       IF (m >= 0) THEN
     876              : 
     877            0 : !$OMP       DO
     878              : 
     879              :          DO ip = 1, SIZE(s)
     880            0 :             x = s(ip)
     881            0 :             t3 = b**2
     882            0 :             t4 = x**2
     883            0 :             t7 = SQRT(o + t3*t4)
     884            0 :             t9 = LOG(b*x + t7)
     885            0 :             t10 = a1*x*t9
     886            0 :             t12 = EXP(-a4*t4)
     887            0 :             t17 = t4**2
     888            0 :             fs(ip, 1) = (o + t10 + (a2 - a3*t12)*t4)/(o + t10 + a5*t17)
     889              :          END DO
     890              : 
     891              : !$OMP       END DO
     892              : 
     893              :       END IF
     894            0 :       IF (m >= 1) THEN
     895              : 
     896            0 : !$OMP       DO
     897              : 
     898              :          DO ip = 1, SIZE(s)
     899            0 :             x = s(ip)
     900            0 :             t2 = b**2
     901            0 :             t3 = x**2
     902            0 :             t6 = SQRT(o + t2*t3)
     903            0 :             t7 = b*x + t6
     904            0 :             t8 = LOG(t7)
     905            0 :             t9 = a1*t8
     906            0 :             t10 = a1*x
     907            0 :             t17 = t10*(b + 1/t6*t2*x)/t7
     908            0 :             t19 = t3*x
     909            0 :             t21 = EXP(-a4*t3)
     910            0 :             t26 = a2 - a3*t21
     911            0 :             t30 = t10*t8
     912            0 :             t31 = t3**2
     913            0 :             t33 = o + t30 + a5*t31
     914            0 :             t38 = t33**2
     915              :             fs(ip, 2) = &
     916              :                (t9 + t17 + 2._dp*a3*a4*t19*t21 + 2._dp*t26*x)/ &
     917            0 :                t33 - (o + t30 + t26*t3)/t38*(t9 + t17 + 4._dp*a5*t19)
     918              :          END DO
     919              : 
     920              : !$OMP       END DO
     921              : 
     922              :       END IF
     923            0 :       IF (m >= 2) THEN
     924              : 
     925            0 : !$OMP       DO
     926              : 
     927              :          DO ip = 1, SIZE(s)
     928            0 :             x = s(ip)
     929            0 :             t1 = b**2
     930            0 :             t2 = x**2
     931            0 :             t5 = SQRT(o + t1*t2)
     932            0 :             t7 = o/t5*t1
     933            0 :             t9 = b + t7*x
     934            0 :             t12 = b*x + t5
     935            0 :             t13 = o/t12
     936            0 :             t15 = 2._dp*a1*t9*t13
     937            0 :             t16 = a1*x
     938            0 :             t17 = t5**2
     939            0 :             t20 = t1**2
     940            0 :             t25 = t16*(-o/t17/t5*t20*t2 + t7)*t13
     941            0 :             t26 = t9**2
     942            0 :             t27 = t12**2
     943            0 :             t30 = t16*t26/t27
     944            0 :             t31 = a3*a4
     945            0 :             t33 = EXP(-a4*t2)
     946            0 :             t37 = a4**2
     947            0 :             t39 = t2**2
     948            0 :             t44 = a3*t33
     949            0 :             t47 = LOG(t12)
     950            0 :             t48 = t16*t47
     951            0 :             t50 = o + t48 + a5*t39
     952            0 :             t53 = a1*t47
     953            0 :             t55 = t16*t9*t13
     954            0 :             t56 = t2*x
     955            0 :             t60 = a2 - t44
     956            0 :             t64 = t50**2
     957            0 :             t65 = o/t64
     958            0 :             t69 = t53 + t55 + 4._dp*a5*t56
     959            0 :             t73 = o + t48 + t60*t2
     960            0 :             t77 = t69**2
     961              :             fs(ip, 3) = &
     962              :                (t15 + t25 - t30 + 10._dp*t31*t2*t33 - 4._dp*a3*t37*t39*t33 + &
     963              :                 2._dp*a2 - 2._dp*t44)/t50 - 2._dp* &
     964              :                (t53 + t55 + 2._dp*t31*t56*t33 + 2._dp*t60*x)* &
     965            0 :                t65*t69 + 2._dp*t73/t64/t50*t77 - t73*t65*(t15 + t25 - t30 + 12._dp*a5*t2)
     966              :          END DO
     967              : 
     968              : !$OMP       END DO
     969              : 
     970              :       END IF
     971            0 :       IF (m >= 3) THEN
     972              : 
     973            0 : !$OMP       DO
     974              : 
     975              :          DO ip = 1, SIZE(s)
     976            0 :             x = s(ip)
     977            0 :             t1 = b**2
     978            0 :             t2 = x**2
     979            0 :             t5 = SQRT(0.1e1_dp + t1*t2)
     980            0 :             t6 = t5**2
     981            0 :             t9 = t1**2
     982            0 :             t10 = 1/t6/t5*t9
     983            0 :             t13 = 1/t5*t1
     984            0 :             t14 = -t10*t2 + t13
     985            0 :             t17 = b*x + t5
     986            0 :             t18 = 1/t17
     987            0 :             t20 = 3*a1*t14*t18
     988            0 :             t22 = b + t13*x
     989            0 :             t23 = t22**2
     990            0 :             t25 = t17**2
     991            0 :             t26 = 1/t25
     992            0 :             t28 = 3*a1*t23*t26
     993            0 :             t29 = a1*x
     994            0 :             t30 = t6**2
     995            0 :             t35 = t2*x
     996            0 :             t40 = 3*t29*(1/t30/t5*t1*t9*t35 - t10*x)*t18
     997            0 :             t44 = 3*t29*t14*t26*t22
     998            0 :             t50 = 2*t29*t23*t22/t25/t17
     999            0 :             t51 = a3*a4
    1000            0 :             t53 = EXP(-a4*t2)
    1001            0 :             t57 = a4**2
    1002            0 :             t58 = a3*t57
    1003            0 :             t59 = t35*t53
    1004            0 :             t64 = t2**2
    1005            0 :             t70 = LOG(t17)
    1006            0 :             t71 = t29*t70
    1007            0 :             t73 = 0.1e1_dp + t71 + a5*t64
    1008            0 :             t78 = 2*a1*t22*t18
    1009            0 :             t80 = t29*t14*t18
    1010            0 :             t82 = t29*t23*t26
    1011            0 :             t90 = a3*t53
    1012            0 :             t93 = t73**2
    1013            0 :             t94 = 1/t93
    1014            0 :             t96 = a1*t70
    1015            0 :             t98 = t29*t18*t22
    1016            0 :             t101 = t96 + t98 + 4*a5*t35
    1017            0 :             t106 = a2 - t90
    1018            0 :             t109 = t96 + t98 + 2*t51*t59 + 2*t106*x
    1019            0 :             t111 = 1/t93/t73
    1020            0 :             t113 = t101**2
    1021            0 :             t119 = t78 + t80 - t82 + 12*a5*t2
    1022            0 :             t123 = 0.1e1_dp + t71 + t106*t2
    1023            0 :             t124 = t93**2
    1024              :             fs(ip, 4) = &
    1025              :                (t20 - t28 + t40 - t44 + t50 + 24*t51*x*t53 - 36._dp*t58*t59 + 8._dp*a3*t57*a4*t64* &
    1026              :                 x*t53)/t73 - 3._dp*(t78 + t80 - t82 + 10._dp*t51*t2*t53 - &
    1027              :                                     4._dp*t58*t64*t53 + 2._dp*a2 - 2._dp*t90)*t94*t101 + &
    1028              :                6._dp*t109*t111*t113 - 3._dp*t109*t94*t119 - 6*t123/t124*t113*t101 + &
    1029            0 :                6._dp*t123*t111*t101*t119 - t123*t94*(t20 - t28 + t40 - t44 + t50 + 24._dp*a5*x)
    1030              :          END DO
    1031              : 
    1032              : !$OMP       END DO
    1033              : 
    1034              :       END IF
    1035              : 
    1036            0 :    END SUBROUTINE efactor_pw91
    1037              : 
    1038              : ! **************************************************************************************************
    1039              : !> \brief ...
    1040              : !> \param s ...
    1041              : !> \param fs ...
    1042              : !> \param m ...
    1043              : !> \param pset ...
    1044              : ! **************************************************************************************************
    1045            0 :    SUBROUTINE efactor_pbex(s, fs, m, pset)
    1046              :       REAL(KIND=dp), DIMENSION(:), INTENT(IN)            :: s
    1047              :       REAL(KIND=dp), DIMENSION(:, :), INTENT(OUT)        :: fs
    1048              :       INTEGER, INTENT(IN)                                :: m, pset
    1049              : 
    1050              :       REAL(KIND=dp), PARAMETER                           :: kappa1 = 0.804_dp, kappa2 = 1.245_dp, &
    1051              :                                                             mu = 0.2195149727645171_dp
    1052              : 
    1053              :       INTEGER                                            :: ip
    1054              :       REAL(KIND=dp)                                      :: f0, mk, x, x2, y
    1055              : 
    1056              :       IF (pset == 1) mk = mu/kappa1
    1057            0 :       IF (pset == 2) mk = mu/kappa2
    1058              : 
    1059            0 :       f0 = 1.0_dp/tact
    1060              : 
    1061              : !$OMP     PARALLEL DO DEFAULT(NONE) &
    1062              : !$OMP                 SHARED (s, fs, m, mk, f0) &
    1063            0 : !$OMP                 PRIVATE(ip,x,x2,y)
    1064              : 
    1065              :       DO ip = 1, SIZE(s)
    1066              :          x = s(ip)*f0
    1067              :          x2 = x*x
    1068              :          y = 1.0_dp/(1.0_dp + mk*x2)
    1069              :          SELECT CASE (m)
    1070              :          CASE (0)
    1071              :             fs(ip, 1) = 1.0_dp + mu*x2*y
    1072              :          CASE (1)
    1073              :             fs(ip, 1) = 1.0_dp + mu*x2*y
    1074              :             fs(ip, 2) = 2.0_dp*mu*x*y*y*f0
    1075              :          CASE (2)
    1076              :             fs(ip, 1) = 1.0_dp + mu*x2*y
    1077              :             fs(ip, 2) = 2.0_dp*mu*x*y*y*f0
    1078              :             fs(ip, 3) = -2.0_dp*mu*(3.0_dp*mk*x2 - 1.0_dp)*y*y*y*f0*f0
    1079              :          CASE (3)
    1080              :             fs(ip, 1) = 1.0_dp + mu*x2*y
    1081              :             fs(ip, 2) = 2.0_dp*mu*x*y*y*f0
    1082              :             fs(ip, 3) = -2.0_dp*mu*(3.0_dp*mk*x2 - 1.0_dp)*y*y*y*f0*f0
    1083              :             fs(ip, 4) = 24.0_dp*mu*mk*x*(mk*x2 - 1.0_dp)*y*y*y*y*f0*f0*f0
    1084              :          CASE DEFAULT
    1085              :             CPABORT("Illegal order")
    1086              :          END SELECT
    1087              :       END DO
    1088              : 
    1089              : !$OMP     END PARALLEL DO
    1090              : 
    1091            0 :    END SUBROUTINE efactor_pbex
    1092              : 
    1093              : END MODULE xc_exchange_gga
    1094              : 
        

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