types_xcpot_libxc.F90 8.07 KB
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!--------------------------------------------------------------------------------
! Copyright (c) 2016 Peter Grünberg Institut, Forschungszentrum Jülich, Germany
! This file is part of FLEUR and available as free software under the conditions
! of the MIT license as expressed in the LICENSE file in more detail.
!--------------------------------------------------------------------------------

!>This module contains the xcpot-type providing an interface to libxc
MODULE m_types_xcpot_libxc
#ifdef CPP_LIBXC  
  USE xc_f03_lib_m
#endif
  USE m_types_xcpot
  USE m_judft
  IMPLICIT NONE
  PRIVATE

  TYPE,EXTENDS(t_xcpot):: t_xcpot_libxc 
#ifdef CPP_LIBXC    
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     TYPE(xc_f03_func_t) :: xc_func_x,xc_func_c
     TYPE(xc_f03_func_info_t) :: xc_info_x,xc_info_c
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#endif
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     INTEGER          :: func_id_c,func_id_x,jspins
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   CONTAINS
     PROCEDURE        :: is_gga=>xcpot_is_gga
     PROCEDURE        :: is_hybrid=>xcpot_is_hybrid 
     PROCEDURE        :: get_exchange_weight=>xcpot_get_exchange_weight
     PROCEDURE        :: get_vxc=>xcpot_get_vxc
     PROCEDURE        :: get_exc=>xcpot_get_exc
     PROCEDURE,NOPASS :: alloc_gradients=>xcpot_alloc_gradients
     !Not overloeaded...
     PROCEDURE        :: init=>xcpot_init
  END TYPE t_xcpot_libxc
  PUBLIC t_xcpot_libxc
CONTAINS

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  SUBROUTINE xcpot_init(xcpot,jspins,id_x,id_c)
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    USE m_judft
    IMPLICIT NONE
    CLASS(t_xcpot_libxc),INTENT(OUT)    :: xcpot
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    INTEGER,INTENT(IN)                  :: jspins,id_x,id_c
    
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#ifdef CPP_LIBXC
    INTEGER :: err
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    xcpot%jspins=jspins
    xcpot%func_id_x=id_x
    xcpot%func_id_c=id_c
 
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    IF (jspins==1) THEN
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       CALL xc_f03_func_init(xcpot%xc_func_x, xcpot%func_id_x, XC_UNPOLARIZED)
       IF (xcpot%func_id_c>0) CALL xc_f03_func_init(xcpot%xc_func_c, xcpot%func_id_c, XC_UNPOLARIZED)
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    ELSE
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       CALL xc_f03_func_init(xcpot%xc_func_x, xcpot%func_id_x, XC_POLARIZED)
       IF (xcpot%func_id_c>0) CALL xc_f03_func_init(xcpot%xc_func_c, xcpot%func_id_c, XC_POLARIZED)
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    END IF
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    xcpot%xc_info_x=xc_f03_func_get_info(xcpot%xc_func_x)
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    CALL priv_write_info(xcpot%xc_info_x)
    IF (xcpot%func_id_c>0) THEN
       xcpot%xc_info_c=xc_f03_func_get_info(xcpot%xc_func_c)
       CALL priv_write_info(xcpot%xc_info_c)
    ELSE
       WRITE(*,*) "No Correlation functional"
    END IF
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#else
    CALL judft_error("You specified a libxc-exchange correlation potential but FLEUR is not linked against libxc",hint="Please recompile FLEUR with libxc support")
#endif
  END SUBROUTINE xcpot_init


  LOGICAL FUNCTION xcpot_is_gga(xcpot)
    IMPLICIT NONE
    CLASS(t_xcpot_libxc),INTENT(IN):: xcpot
#ifdef CPP_LIBXC    
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    xcpot_is_gga=ANY((/XC_FAMILY_GGA, XC_FAMILY_HYB_GGA/)==xc_f03_func_info_get_family(xcpot%xc_info_x))
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#endif
  END FUNCTION xcpot_is_gga

  LOGICAL FUNCTION xcpot_is_hybrid(xcpot)
    IMPLICIT NONE
    CLASS(t_xcpot_libxc),INTENT(IN):: xcpot
#ifdef CPP_LIBXC
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    xcpot_is_hybrid=ANY((/XC_FAMILY_HYB_MGGA, XC_FAMILY_HYB_GGA/)==xc_f03_func_info_get_family(xcpot%xc_info_x))
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#endif
  END FUNCTION xcpot_is_hybrid

  FUNCTION xcpot_get_exchange_weight(xcpot) RESULT(a_ex)
    USE m_judft
    IMPLICIT NONE
    CLASS(t_xcpot_libxc),INTENT(IN):: xcpot

    REAL:: a_ex
#ifdef CPP_LIBXC    
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    a_ex=xc_f03_hyb_exx_coef(xcpot%xc_func_x)
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#endif
  END FUNCTION xcpot_get_exchange_weight

  !***********************************************************************
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  SUBROUTINE xcpot_get_vxc(xcpot,jspins,rh, vxc,vx, grad,drdsigma)
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    !***********************************************************************
    IMPLICIT NONE
    CLASS(t_xcpot_libxc),INTENT(IN) :: xcpot
    INTEGER, INTENT (IN)     :: jspins
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    REAL,INTENT (IN)         :: rh(:,:)   !Dimensions here
    REAL, INTENT (OUT)       :: vx (:,:)  !points,spin
    REAL, INTENT (OUT  )     :: vxc(:,:)  !
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    ! optional arguments for GGA
    TYPE(t_gradients),OPTIONAL,INTENT(IN)::grad
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    REAL,ALLOCATABLE,OPTIONAL,INTENT(OUT)::drdsigma(:)
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#ifdef CPP_LIBXC    
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    REAL,ALLOCATABLE::vxc_tmp(:,:),vx_tmp(:,:),vsigma(:)
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    !libxc uses the spin as a first index, hence we have to transpose....
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    ALLOCATE(vxc_tmp(SIZE(vxc,2),SIZE(vxc,1)));vxc_tmp=0.0
    ALLOCATE(vx_tmp(SIZE(vx,2),SIZE(vx,1)));vx_tmp=0.0
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    IF (xcpot%is_gga()) THEN
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       CALL judft_error("libxc GGA not implemented yet")
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       IF (.NOT.PRESENT(grad)) CALL judft_error("Bug: You called get_vxc for a GGA potential without providing derivatives")
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       ALLOCATE(drdsigma(SIZE(grad%sigma)))
       CALL xc_f03_gga_vxc(xcpot%xc_func_x, SIZE(rh,1), TRANSPOSE(rh),grad%sigma,vx_tmp,drdsigma)
       IF (xcpot%func_id_c>0) THEN
          ALLOCATE(vsigma(SIZE(grad%sigma)))
          CALL xc_f03_gga_vxc(xcpot%xc_func_c, SIZE(rh,1), TRANSPOSE(rh),grad%sigma,vxc_tmp,vsigma)
          drdsigma=drdsigma+vsigma
          vxc_tmp=vxc_tmp+vx_tmp
       ENDIF
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    ELSE  !LDA potentials
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       CALL xc_f03_lda_vxc(xcpot%xc_func_x, SIZE(rh,1), TRANSPOSE(rh), vx_tmp)
       IF (xcpot%func_id_c>0) THEN
          CALL xc_f03_lda_vxc(xcpot%xc_func_c, SIZE(rh,1), TRANSPOSE(rh), vxc_tmp)
          vxc_tmp=vxc_tmp+vx_tmp
       ENDIF
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    ENDIF
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    vx=TRANSPOSE(vx_tmp) 
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    vxc=TRANSPOSE(vxc_tmp) 
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#endif
  END SUBROUTINE xcpot_get_vxc

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  !***********************************************************************
  SUBROUTINE xcpot_get_exc(xcpot,jspins,rh,exc,grad)
    !***********************************************************************
    IMPLICIT NONE
    CLASS(t_xcpot_libxc),INTENT(IN) :: xcpot
    INTEGER, INTENT (IN)     :: jspins
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    REAL,INTENT (IN) :: rh(:,:)  !points,spin
    REAL, INTENT (OUT) :: exc(:) !points
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    ! optional arguments for GGA      
    TYPE(t_gradients),OPTIONAL,INTENT(IN)::grad
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    REAL  :: excc(SIZE(exc))
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#ifdef CPP_LIBXC    
    IF (xcpot%is_gga()) THEN
       IF (.NOT.PRESENT(grad)) CALL judft_error("Bug: You called get_vxc for a GGA potential without providing derivatives")
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       CALL xc_f03_gga_exc(xcpot%xc_func_x, SIZE(rh,1), TRANSPOSE(rh),grad%sigma,exc)
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       IF (xcpot%func_id_c>0) THEN
          CALL xc_f03_gga_exc(xcpot%xc_func_c, SIZE(rh,1), TRANSPOSE(rh),grad%sigma,excc)
          exc=exc+excc
       END IF
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    ELSE  !LDA potentials
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       CALL xc_f03_lda_exc(xcpot%xc_func_x, SIZE(rh,1), TRANSPOSE(rh), exc)
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       IF (xcpot%func_id_c>0) THEN
          CALL xc_f03_lda_exc(xcpot%xc_func_c, SIZE(rh,1), TRANSPOSE(rh), excc)
          exc=exc+excc
       END IF
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    ENDIF
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#endif
  END SUBROUTINE xcpot_get_exc

  SUBROUTINE xcpot_alloc_gradients(ngrid,jspins,grad)
    INTEGER, INTENT (IN)         :: jspins,ngrid
    TYPE(t_gradients),INTENT(OUT):: grad
    !For libxc we only need the sigma array...
    ALLOCATE(grad%sigma(MERGE(1,3,jspins==1),ngrid))
  END SUBROUTINE xcpot_alloc_gradients


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#ifdef CPP_LIBXC
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  SUBROUTINE priv_write_info(xc_info)
    IMPLICIT NONE
    TYPE(xc_f03_func_info_t),INTENT(IN) :: xc_info
    INTEGER :: i
    CHARACTER(len=120) :: kind, family
    
    SELECT CASE(xc_f03_func_info_get_kind(xc_info))
    CASE (XC_EXCHANGE)
       WRITE(kind, '(a)') 'an exchange functional'
    CASE (XC_CORRELATION)
       WRITE(kind, '(a)') 'a correlation functional'
    CASE (XC_EXCHANGE_CORRELATION)
       WRITE(kind, '(a)') 'an exchange-correlation functional'
    CASE (XC_KINETIC)
       WRITE(kind, '(a)') 'a kinetic energy functional'
    CASE default
       WRITE(kind, '(a)') 'of unknown kind'
    END SELECT
    SELECT CASE (xc_f03_func_info_get_family(xc_info))
    CASE (XC_FAMILY_LDA);
       WRITE(family,'(a)') "LDA"
    CASE (XC_FAMILY_GGA);
       WRITE(family,'(a)') "GGA"
    CASE (XC_FAMILY_HYB_GGA);
       WRITE(family,'(a)') "Hybrid GGA"
    CASE (XC_FAMILY_MGGA);
       WRITE(family,'(a)') "MGGA"
    CASE (XC_FAMILY_HYB_MGGA);
       WRITE(family,'(a)') "Hybrid MGGA"
    CASE default;
       WRITE(family,'(a)') "unknown"
    END SELECT
    
    WRITE(*,'("The functional ''", a, "'' is ", a, ", it belongs to the ''", a, "'' family and is defined in the reference(s):")') &
         TRIM(xc_f03_func_info_get_name(xc_info)), TRIM(kind), TRIM(family)
    
    i = 0
    DO WHILE(i >= 0)
       WRITE(*, '(a,i1,2a)') '[', i+1, '] ', TRIM(xc_f03_func_reference_get_ref(xc_f03_func_info_get_references(xc_info, i)))
    END DO
  END SUBROUTINE priv_write_info
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#endif
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END MODULE m_types_xcpot_libxc