quantum-espresso/Modules/cell_base.f90

876 lines
28 KiB
Fortran

!
! Copyright (C) 2002 FPMD group
! This file is distributed under the terms of the
! GNU General Public License. See the file `License'
! in the root directory of the present distribution,
! or http://www.gnu.org/copyleft/gpl.txt .
!
!------------------------------------------------------------------------------!
MODULE cell_base
!------------------------------------------------------------------------------!
USE kinds, ONLY : dbl
!
IMPLICIT NONE
SAVE
!
! ... periodicity box
! ... In the matrix "a" every row is the vector of each side of
! ... the cell in the real space
TYPE boxdimensions
REAL(dbl) :: a(3,3) ! direct lattice generators
REAL(dbl) :: m1(3,3) ! reciprocal lattice generators
REAL(dbl) :: omega ! cell volume = determinant of a
REAL(dbl) :: g(3,3) ! metric tensor
REAL(dbl) :: pail(3,3) ! stress tensor
REAL(dbl) :: hmat(3,3) ! cell parameters ( transpose of "a" )
REAL(dbl) :: hvel(3,3) ! cell velocity
REAL(dbl) :: hinv(3,3)
REAL(dbl) :: deth
INTEGER :: perd(3)
END TYPE boxdimensions
REAL(dbl) :: alat = 0.0d0 ! lattice parameter, often used to scale quantities
! or in combination to other parameters/constants
! to define new units
! celldm are che simulation cell parameters
REAL(dbl) :: celldm(6) = (/ 0.0d0, 0.0d0, 0.0d0, 0.0d0, 0.0d0, 0.0d0 /)
! a1, a2 and a3 are the simulation cell base vector as calculated from celldm
REAL(dbl) :: a1(3) = (/ 0.0d0, 0.0d0, 0.0d0 /)
REAL(dbl) :: a2(3) = (/ 0.0d0, 0.0d0, 0.0d0 /)
REAL(dbl) :: a3(3) = (/ 0.0d0, 0.0d0, 0.0d0 /)
REAL(dbl) :: ainv(3,3) = 0.0d0
REAl(dbl) :: omega = 0.0d0 ! volume of the simulation cell
REAL(dbl) :: tpiba = 0.0d0 ! = 2 PI / alat
REAL(dbl) :: tpiba2 = 0.0d0 ! = ( 2 PI / alat ) ** 2
! direct lattice vectors and reciprocal lattice vectors
! The folloving relations should alwais be kept valid
! at( :, 1 ) = a1( : ) / alat ; h( :, 1 ) = a1( : )
! at( :, 2 ) = a2( : ) / alat ; h( :, 2 ) = a2( : )
! at( :, 3 ) = a3( : ) / alat ; h( :, 3 ) = a3( : )
! ht = h^t ; ainv = h^(-1)
!
! bg( :, 1 ) = b1( : )
! bg( :, 2 ) = b2( : )
! bg( :, 3 ) = b3( : )
REAL(dbl) :: at(3,3) = RESHAPE( (/ 0.0d0 /), (/ 3, 3 /), (/ 0.0d0 /) )
REAL(dbl) :: bg(3,3) = RESHAPE( (/ 0.0d0 /), (/ 3, 3 /), (/ 0.0d0 /) )
INTEGER :: ibrav ! index of the bravais lattice
CHARACTER(len=9) :: symm_type ! 'cubic' or 'hexagonal' when ibrav=0
REAL(dbl) :: h(3,3) = 0.0d0 ! simulation cell at time t
REAL(dbl) :: hold(3,3) = 0.0d0 ! simulation cell at time t-delt
REAL(dbl) :: deth = 0.0d0 ! determinant of h ( cell volume )
INTEGER :: iforceh(3,3) = 1 ! if iforceh( i, j ) = 0 then h( i, j )
! is not allowed to move
LOGICAL :: thdiag = .FALSE. ! True if only cell diagonal elements
! should be updated
REAL(dbl) :: wmass = 0.0d0 ! cell fictitious mass
REAL(dbl) :: press = 0.0d0 ! external pressure
REAL(dbl) :: frich = 0.0d0 ! firction parameter for cell damped dynamics
REAL(dbl) :: greash = 1.0d0 ! greas parameter for damped dynamics
LOGICAL :: tcell_base_init = .FALSE.
INTERFACE cell_init
MODULE PROCEDURE cell_init_ht, cell_init_a
END INTERFACE
INTERFACE pbcs
MODULE PROCEDURE pbcs_components, pbcs_vectors
END INTERFACE
INTERFACE s_to_r
MODULE PROCEDURE s_to_r1, s_to_r1b, s_to_r3
END INTERFACE
INTERFACE r_to_s
MODULE PROCEDURE r_to_s1, r_to_s1b, r_to_s3
END INTERFACE
!
!------------------------------------------------------------------------------!
CONTAINS
!------------------------------------------------------------------------------!
!
SUBROUTINE updatecell(box_tm2, box_tm1, box_t0, box_tp1)
type (boxdimensions) :: box_tm2, box_tm1, box_t0, box_tp1
box_tm2 = box_tm1
box_tm1 = box_t0
box_t0 = box_tp1
RETURN
END SUBROUTINE UPDATECELL
!------------------------------------------------------------------------------!
SUBROUTINE dgcell(gcm1, gcdot, box_tm2, box_tm1, box_t0, delt)
REAL(dbl) :: GCM1(3,3)
REAL(dbl) :: GCDOT(3,3)
REAL(dbl) :: delt
type (boxdimensions), intent(in) :: box_tm2, box_tm1, box_t0
REAL(dbl) :: DUM
CALL invmat(3,box_t0%G,GCM1,DUM)
GCDOT = (3.D0*box_t0%G - 4.D0*box_tm1%G + box_tm2%G)/ (2.0d0 * delt )
RETURN
END SUBROUTINE DGCELL
!------------------------------------------------------------------------------!
! ... set box
! ... box%m1(i,1) == b1(i) COLUMN are B vectors
! ... box%a(1,i) == a1(i) ROW are A vector
! ... box%omega == volume
! ... box%g(i,j) == metric tensor G
!------------------------------------------------------------------------------!
SUBROUTINE cell_init_ht( box, ht )
TYPE (boxdimensions) :: box
REAL(dbl) :: ht(3,3)
box%a = ht
box%hmat = TRANSPOSE( ht )
CALL gethinv( box )
box%g = MATMUL( box%a(:,:), box%hmat(:,:) )
box%hvel = 0.0d0
box%pail = 0.0d0
RETURN
END SUBROUTINE
!------------------------------------------------------------------------------!
SUBROUTINE cell_init_a( box, a1, a2, a3 )
TYPE (boxdimensions) :: box
REAL(dbl) :: a1(3), a2(3), a3(3)
INTEGER :: i
DO i=1,3
box%a(1,I) = A1(I) ! this is HT: the row are the lattice vectors
box%a(2,I) = A2(I)
box%a(3,I) = A3(I)
box%hmat(I,1) = A1(I) ! this is H : the column are the lattice vectors
box%hmat(I,2) = A2(I)
box%hmat(I,3) = A3(I)
END DO
box%pail = 0.0d0
box%hvel = 0.0d0
CALL gethinv(box)
box%g = MATMUL( box%a(:,:), box%hmat(:,:) )
RETURN
END SUBROUTINE
!------------------------------------------------------------------------------!
SUBROUTINE R_TO_S1 (R,S,box)
REAL(dbl), intent(out) :: S(3)
REAL(dbl), intent(in) :: R(3)
type (boxdimensions), intent(in) :: box
integer i,j
DO I=1,3
S(I) = 0.D0
DO J=1,3
S(I) = S(I) + R(J)*box%m1(J,I)
END DO
END DO
RETURN
END SUBROUTINE R_TO_S1
!------------------------------------------------------------------------------!
SUBROUTINE R_TO_S3 ( R, S, na, nsp, hinv )
REAL(dbl), intent(out) :: S(:,:)
INTEGER, intent(in) :: na(:), nsp
REAL(dbl), intent(in) :: R(:,:)
REAL(dbl), intent(in) :: hinv(:,:) ! hinv = TRANSPOSE( box%m1 )
integer :: i, j, ia, is, isa
isa = 0
DO is = 1, nsp
DO ia = 1, na(is)
isa = isa + 1
DO I=1,3
S(I,isa) = 0.D0
DO J=1,3
S(I,isa) = S(I,isa) + R(J,isa)*hinv(i,j)
END DO
END DO
END DO
END DO
RETURN
END SUBROUTINE R_TO_S3
!------------------------------------------------------------------------------!
SUBROUTINE R_TO_S1B ( R, S, hinv )
REAL(dbl), intent(out) :: S(:)
REAL(dbl), intent(in) :: R(:)
REAL(dbl), intent(in) :: hinv(:,:) ! hinv = TRANSPOSE( box%m1 )
integer :: i, j
DO I=1,3
S(I) = 0.D0
DO J=1,3
S(I) = S(I) + R(J)*hinv(i,j)
END DO
END DO
RETURN
END SUBROUTINE R_TO_S1B
!------------------------------------------------------------------------------!
SUBROUTINE s_to_r1 (S,R,box)
REAL(dbl), intent(in) :: S(3)
REAL(dbl), intent(out) :: R(3)
type (boxdimensions), intent(in) :: box
integer i,j
DO I=1,3
R(I) = 0.D0
DO J=1,3
R(I) = R(I) + S(J)*box%a(J,I)
END DO
END DO
RETURN
END SUBROUTINE s_to_r1
!------------------------------------------------------------------------------!
SUBROUTINE s_to_r1b (S,R,h)
REAL(dbl), intent(in) :: S(3)
REAL(dbl), intent(out) :: R(3)
REAL(dbl), intent(in) :: h(:,:) ! h = TRANSPOSE( box%a )
integer i,j
DO I=1,3
R(I) = 0.D0
DO J=1,3
R(I) = R(I) + S(J)*h(I,j)
END DO
END DO
RETURN
END SUBROUTINE s_to_r1b
!------------------------------------------------------------------------------!
SUBROUTINE s_to_r3 ( S, R, na, nsp, h )
REAL(dbl), intent(in) :: S(:,:)
INTEGER, intent(in) :: na(:), nsp
REAL(dbl), intent(out) :: R(:,:)
REAL(dbl), intent(in) :: h(:,:) ! h = TRANSPOSE( box%a )
integer :: i, j, ia, is, isa
isa = 0
DO is = 1, nsp
DO ia = 1, na(is)
isa = isa + 1
DO I = 1, 3
R(I,isa) = 0.D0
DO J = 1, 3
R(I,isa) = R(I,isa) + S(J,isa) * h(I,j)
END DO
END DO
END DO
END DO
RETURN
END SUBROUTINE s_to_r3
!
!------------------------------------------------------------------------------!
!
SUBROUTINE gethinv(box)
IMPLICIT NONE
TYPE (boxdimensions), INTENT (INOUT) :: box
REAL (dbl), DIMENSION (3,3) :: hmat, hmati
REAL (dbl) :: odet
hmat = box%hmat
box%deth = hmat(1,1)*(hmat(2,2)*hmat(3,3)-hmat(2,3)*hmat(3,2)) + &
hmat(1,2)*(hmat(2,3)*hmat(3,1)-hmat(2,1)*hmat(3,3)) + &
hmat(1,3)*(hmat(2,1)*hmat(3,2)-hmat(2,2)*hmat(3,1))
IF (box%deth<1.E-10) &
CALL errore('gethinv', 'box determinant too small', 1)
odet = 1._dbl/box%deth
hmati(1,1) = (hmat(2,2)*hmat(3,3)-hmat(2,3)*hmat(3,2))*odet
hmati(2,2) = (hmat(1,1)*hmat(3,3)-hmat(1,3)*hmat(3,1))*odet
hmati(3,3) = (hmat(1,1)*hmat(2,2)-hmat(1,2)*hmat(2,1))*odet
hmati(1,2) = (hmat(1,3)*hmat(3,2)-hmat(1,2)*hmat(3,3))*odet
hmati(2,1) = (hmat(3,1)*hmat(2,3)-hmat(2,1)*hmat(3,3))*odet
hmati(1,3) = (hmat(1,2)*hmat(2,3)-hmat(1,3)*hmat(2,2))*odet
hmati(3,1) = (hmat(2,1)*hmat(3,2)-hmat(3,1)*hmat(2,2))*odet
hmati(2,3) = (hmat(1,3)*hmat(2,1)-hmat(2,3)*hmat(1,1))*odet
hmati(3,2) = (hmat(3,1)*hmat(1,2)-hmat(3,2)*hmat(1,1))*odet
box%hinv = hmati
CALL invmat( 3, box%a, box%m1, box%omega )
IF(abs(box%omega-box%deth)/abs(box%omega+box%deth).gt.1.0d-12) THEN
CALL errore('gethinv', 'box determinants are different',2)
END IF
END SUBROUTINE gethinv
!
!------------------------------------------------------------------------------!
!
FUNCTION pbc(rin,box,nl) RESULT (rout)
IMPLICIT NONE
TYPE (boxdimensions) :: box
REAL (dbl) :: rin(3)
REAL (dbl) :: rout(3), s(3)
INTEGER, OPTIONAL :: nl(3)
s = matmul(box%hinv(:,:),rin)
s = s - box%perd*nint(s)
rout = matmul(box%hmat(:,:),s)
IF (present(nl)) THEN
s = dble(nl)
rout = rout + matmul(box%hmat(:,:),s)
END IF
END FUNCTION pbc
!
!------------------------------------------------------------------------------!
!
SUBROUTINE get_cell_param(box,cell,ang)
IMPLICIT NONE
TYPE(boxdimensions), INTENT(in) :: box
REAL(dbl), INTENT(out), DIMENSION(3) :: cell
REAL(dbl), INTENT(out), DIMENSION(3), OPTIONAL :: ang
! This code gets the cell parameters given the h-matrix:
! a
cell(1)=sqrt(box%hmat(1,1)*box%hmat(1,1)+box%hmat(2,1)*box%hmat(2,1) &
+box%hmat(3,1)*box%hmat(3,1))
! b
cell(2)=sqrt(box%hmat(1,2)*box%hmat(1,2)+box%hmat(2,2)*box%hmat(2,2) &
+box%hmat(3,2)*box%hmat(3,2))
! c
cell(3)=sqrt(box%hmat(1,3)*box%hmat(1,3)+box%hmat(2,3)*box%hmat(2,3) &
+box%hmat(3,3)*box%hmat(3,3))
IF (PRESENT(ang)) THEN
! gamma
ang(1)=acos((box%hmat(1,1)*box%hmat(1,2)+ &
box%hmat(2,1)*box%hmat(2,2) &
+box%hmat(3,1)*box%hmat(3,2))/(cell(1)*cell(2)))
! beta
ang(2)=acos((box%hmat(1,1)*box%hmat(1,3)+ &
box%hmat(2,1)*box%hmat(2,3) &
+box%hmat(3,1)*box%hmat(3,3))/(cell(1)*cell(3)))
! alpha
ang(3)=acos((box%hmat(1,2)*box%hmat(1,3)+ &
box%hmat(2,2)*box%hmat(2,3) &
+box%hmat(3,2)*box%hmat(3,3))/(cell(2)*cell(3)))
! ang=ang*180.0_dbl/pi
ENDIF
END SUBROUTINE get_cell_param
!------------------------------------------------------------------------------!
SUBROUTINE pbcs_components(x1, y1, z1, x2, y2, z2, m)
! ... This subroutine compute the periodic boundary conditions in the scaled
! ... variables system
USE kinds
INTEGER, INTENT(IN) :: M
REAL(dbl), INTENT(IN) :: X1,Y1,Z1
REAL(dbl), INTENT(OUT) :: X2,Y2,Z2
REAL(dbl) MIC
MIC = REAL(M)
X2 = X1 - DNINT(X1/MIC)*MIC
Y2 = Y1 - DNINT(Y1/MIC)*MIC
Z2 = Z1 - DNINT(Z1/MIC)*MIC
RETURN
END SUBROUTINE
!------------------------------------------------------------------------------!
SUBROUTINE pbcs_vectors(v, w, m)
! ... This subroutine compute the periodic boundary conditions in the scaled
! ... variables system
USE kinds
INTEGER, INTENT(IN) :: m
REAL(dbl), INTENT(IN) :: v(3)
REAL(dbl), INTENT(OUT) :: w(3)
REAL(dbl) :: MIC
MIC = REAL(M)
w(1) = v(1) - DNINT(v(1)/MIC)*MIC
w(2) = v(2) - DNINT(v(2)/MIC)*MIC
w(3) = v(3) - DNINT(v(3)/MIC)*MIC
RETURN
END SUBROUTINE
!------------------------------------------------------------------------------!
SUBROUTINE cell_base_init( ibrav_ , celldm_ , trd_ht, cell_symmetry, rd_ht, &
a_ , b_ , c_ , cosab, cosac, cosbc, wc_ , total_ions_mass , press_ , &
frich_ , greash_ , cell_dofree )
USE constants, ONLY: bohr_radius_angs, gpa_au, pi, uma_au
USE io_global, ONLY: stdout
IMPLICIT NONE
INTEGER, INTENT(IN) :: ibrav_
REAL(dbl), INTENT(IN) :: celldm_ (6)
LOGICAL, INTENT(IN) :: trd_ht
CHARACTER(LEN=*), INTENT(IN) :: cell_symmetry
REAL(dbl), INTENT(IN) :: rd_ht (3,3)
REAL(dbl), INTENT(IN) :: a_ , b_ , c_ , cosab, cosac, cosbc
CHARACTER(LEN=*), INTENT(IN) :: cell_dofree
REAL(dbl), INTENT(IN) :: wc_ , frich_ , greash_ , total_ions_mass
REAL(dbl), INTENT(IN) :: press_ ! external pressure from imput ( GPa )
REAL(dbl) :: b1(3), b2(3), b3(3)
REAL(dbl) :: a, b, c
INTEGER :: j
!
! ... set up crystal lattice, and initialize cell_base module
!
celldm = celldm_
a = a_
b = b_
c = c_
ibrav = ibrav_
press = press_ * gpa_au
! frich = frich_ ! for the time being this is set elsewhere
greash = greash_
WRITE( stdout, * )
WRITE( stdout, * )
WRITE( stdout, 110 ) press_
110 format(' external pressure = ',f15.2,' [GPa]')
wmass = wc_
IF( wmass == 0.d0 ) THEN
wmass = 3.d0 / (4.d0 * pi**2 ) * total_ions_mass
wmass = wmass * UMA_AU
WRITE( stdout,999) wmass
ELSE
WRITE( stdout,998) wmass
END IF
998 format(' wmass (read from input) = ',f15.2,' [AU]',/)
999 format(' wmass (calculated) = ',f15.2,' [AU]',/)
! ... if celldm(1) /= 0 rd_ht should be in unit of alat
IF ( trd_ht ) THEN
symm_type = cell_symmetry
at = TRANSPOSE( rd_ht )
WRITE( stdout, 210 )
WRITE( stdout, 220 ) ( rd_ht( 1, j ), j = 1, 3 )
WRITE( stdout, 220 ) ( rd_ht( 2, j ), j = 1, 3 )
WRITE( stdout, 220 ) ( rd_ht( 3, j ), j = 1, 3 )
IF ( ANY( celldm(1:6) /= 0 ) ) THEN
WRITE( stdout, 230 )
celldm(1:6) = 0.0d0
END IF
IF ( a /= 0 ) THEN
WRITE( stdout, 240 )
a = 0.0d0
b = 0.0d0
c = 0.0d0
END IF
210 format(' initial cell from CELL_PARAMETERS card')
220 format(3X,3F14.8)
230 format(' celldm(1:6) are ignored')
240 format(' a, b, c are ignored')
END IF
IF ( ibrav == 0 .AND. .NOT. trd_ht ) &
CALL errore( ' cell_base_init ', ' ibrav=0: must read cell parameters', 1 )
IF ( ibrav /= 0 .AND. trd_ht ) &
CALL errore( ' cell_base_init ', ' redundant data for cell parameters', 2 )
IF( wmass <= 0.0d0 ) &
CALL errore(' cell_base_init ',' wmass out of range ',0)
IF ( celldm(1) == 0.D0 .AND. a /= 0.D0 ) THEN
IF ( ibrav == 0 ) ibrav = 14
celldm(1) = a / bohr_radius_angs
celldm(2) = b / a
celldm(3) = c / a
celldm(4) = cosab
celldm(5) = cosac
celldm(6) = cosbc
ELSE IF ( celldm(1) /= 0.D0 .AND. a /= 0.D0 ) THEN
CALL errore( ' cell_base_init ', ' do not specify both celldm and a,b,c!', 1 )
END IF
IF ( ibrav == 0 .AND. celldm(1) /= 0.D0 ) THEN
!
! ... input at are in units of alat
!
alat = celldm(1)
ELSE IF ( ibrav == 0 .AND. celldm(1) == 0.D0 ) THEN
!
! ... input at are in atomic units: define alat
!
celldm(1) = SQRT( at(1,1)**2 + at(1,2)**2 + at(1,3)**2 )
alat = celldm(1)
!
! ... bring at to alat units
!
at(:,:) = at(:,:) / alat
ELSE
!
! ... generate at (atomic units)
!
CALL latgen( ibrav, celldm, at(1,1), at(1,2), at(1,3), omega )
alat = celldm(1)
!
! ... bring at to alat units
!
at(:,:) = at(:,:) / alat
END IF
!
a1 = at( :, 1 ) * alat
a2 = at( :, 2 ) * alat
a3 = at( :, 3 ) * alat
CALL volume( alat, at(1,1), at(1,2), at(1,3), omega )
CALL recips( a1, a2, a3, b1, b2, b3 )
ainv( 1, : ) = b1( : )
ainv( 2, : ) = b2( : )
ainv( 3, : ) = b3( : )
bg( :, 1 ) = b1( : )
bg( :, 2 ) = b2( : )
bg( :, 3 ) = b3( : )
tcell_base_init = .TRUE.
thdiag = .false.
SELECT CASE ( TRIM( cell_dofree ) )
CASE ( 'all', 'default' )
iforceh = 1
CASE ( 'volume' )
CALL errore(' metric_setup ', &
' cell_dofree = '//TRIM(cell_dofree)//' not yet implemented ', 1 )
CASE ('x')
iforceh = 0
iforceh(1,1) = 1
CASE ('y')
iforceh = 0
iforceh(2,2) = 1
CASE ('z')
iforceh = 0
iforceh(3,3) = 1
CASE ('xy')
iforceh = 0
iforceh(1,1) = 1
iforceh(2,2) = 1
CASE ('xz')
iforceh = 0
iforceh(1,1) = 1
iforceh(3,3) = 1
CASE ('yz')
iforceh = 0
iforceh(2,2) = 1
iforceh(3,3) = 1
CASE ('xyz')
thdiag = .true.
iforceh = 0
iforceh(1,1) = 1
iforceh(2,2) = 1
iforceh(3,3) = 1
CASE DEFAULT
CALL errore(' metric_setup ',' unknown cell_dofree '//TRIM(cell_dofree), 1 )
END SELECT
RETURN
END SUBROUTINE
!------------------------------------------------------------------------------!
SUBROUTINE cell_steepest( hnew, h, delt, iforceh, fcell )
REAL(kind=8), INTENT(OUT) :: hnew(3,3)
REAL(kind=8), INTENT(IN) :: h(3,3), fcell(3,3)
INTEGER, INTENT(IN) :: iforceh(3,3)
REAL(kind=8), INTENT(IN) :: delt
INTEGER :: i, j
REAL(kind=8) :: dt2
dt2 = delt * delt
DO j=1,3
DO i=1,3
hnew(i,j) = h(i,j) + dt2 * fcell(i,j) * iforceh(i,j)
ENDDO
ENDDO
RETURN
END SUBROUTINE
!------------------------------------------------------------------------------!
SUBROUTINE cell_verlet( hnew, h, hold, delt, iforceh, fcell, frich, tnoseh, hnos )
REAL(kind=8), INTENT(OUT) :: hnew(3,3)
REAL(kind=8), INTENT(IN) :: h(3,3), hold(3,3), hnos(3,3), fcell(3,3)
INTEGER, INTENT(IN) :: iforceh(3,3)
REAL(kind=8), INTENT(IN) :: frich, delt
LOGICAL, INTENT(IN) :: tnoseh
REAL(kind=8) :: htmp(3,3)
REAL(kind=8) :: verl1, verl2, verl3, dt2, ftmp
INTEGER :: i, j
dt2 = delt * delt
IF( tnoseh ) THEN
ftmp = 0.0d0
htmp = hnos
ELSE
ftmp = frich
htmp = 0.0d0
END IF
verl1 = 2. / ( 1. + ftmp )
verl2 = 1. - verl1
verl3 = dt2 / ( 1. + ftmp )
DO j=1,3
DO i=1,3
hnew(i,j) = h(i,j) + ( ( verl1 - 1.0d0 ) * h(i,j) &
& + verl2 * hold(i,j) + &
verl3 * ( fcell(i,j) - htmp(i,j) ) ) * iforceh(i,j)
ENDDO
ENDDO
RETURN
END SUBROUTINE
!------------------------------------------------------------------------------!
subroutine cell_hmove( h, hold, delt, iforceh, fcell )
real(kind=8), intent(out) :: h(3,3)
real(kind=8), intent(in) :: hold(3,3), fcell(3,3)
real(kind=8), intent(in) :: delt
integer, intent(in) :: iforceh(3,3)
real(kind=8) :: dt2by2, fac
integer :: i, j
dt2by2 = .5d0 * delt * delt
fac = dt2by2
do i=1,3
do j=1,3
h(i,j) = hold(i,j) + fac * iforceh(i,j) * fcell(i,j)
end do
end do
return
end subroutine
!------------------------------------------------------------------------------!
subroutine cell_force( fcell, ainv, stress, omega, press, wmass )
real(kind=8), intent(out) :: fcell(3,3)
real(kind=8), intent(in) :: stress(3,3), ainv(3,3)
real(kind=8), intent(in) :: omega, press, wmass
integer :: i, j
do j=1,3
do i=1,3
fcell(i,j) = ainv(j,1)*stress(i,1) + ainv(j,2)*stress(i,2) + ainv(j,3)*stress(i,3)
end do
end do
do j=1,3
do i=1,3
fcell(i,j) = fcell(i,j) - ainv(j,i) * press
end do
end do
fcell = omega * fcell / wmass
return
end subroutine
!------------------------------------------------------------------------------!
subroutine cell_move( hnew, h, hold, delt, iforceh, fcell, frich, tnoseh, vnhh, velh, tsdc )
real(kind=8), intent(out) :: hnew(3,3)
real(kind=8), intent(in) :: h(3,3), hold(3,3), fcell(3,3)
real(kind=8), intent(in) :: vnhh(3,3), velh(3,3)
integer, intent(in) :: iforceh(3,3)
real(kind=8), intent(in) :: frich, delt
logical, intent(in) :: tnoseh, tsdc
real(kind=8) :: hnos(3,3)
if( tnoseh ) then
hnos = vnhh * velh
else
hnos = 0.0d0
end if
!
IF( tsdc ) THEN
call cell_steepest( hnew, h, delt, iforceh, fcell )
ELSE
call cell_verlet( hnew, h, hold, delt, iforceh, fcell, frich, tnoseh, hnos )
END IF
return
end subroutine
!------------------------------------------------------------------------------!
subroutine cell_gamma( hgamma, ainv, h, velh )
implicit none
real(kind=8) :: hgamma(3,3)
real(kind=8), intent(in) :: ainv(3,3), h(3,3), velh(3,3)
integer :: i,j,k,l,m
do i=1,3
do j=1,3
do k=1,3
do l=1,3
do m=1,3
hgamma(i,j)=hgamma(i,j)+ainv(i,l)*ainv(k,l)* &
& (velh(m,k)*h(m,j)+h(m,k)*velh(m,j))
enddo
enddo
enddo
enddo
enddo
return
end subroutine
!------------------------------------------------------------------------------!
subroutine cell_kinene( ekinh, temphh, velh )
use constants, only: factem
implicit none
real(kind=8), intent(out) :: ekinh, temphh(3,3)
real(kind=8), intent(in) :: velh(3,3)
integer :: i,j
ekinh = 0.0d0
do j=1,3
do i=1,3
ekinh=ekinh+0.5*wmass*velh(i,j)*velh(i,j)
temphh(i,j)=factem*wmass*velh(i,j)*velh(i,j)
end do
end do
return
end subroutine
!------------------------------------------------------------------------------!
function cell_alat( )
real(dbl) :: cell_alat
if( .NOT. tcell_base_init ) &
call errore( ' cell_alat ', ' alat has not been set ', 1 )
cell_alat = alat
return
end function
!
!------------------------------------------------------------------------------!
END MODULE cell_base
!------------------------------------------------------------------------------!
!------------------------------------------------------------------------------!
MODULE cell_nose
!------------------------------------------------------------------------------!
USE kinds, ONLY : dbl
!
IMPLICIT NONE
SAVE
REAL(dbl) :: xnhh0(3,3) = 0.0d0
REAL(dbl) :: xnhhm(3,3) = 0.0d0
REAL(dbl) :: xnhhp(3,3) = 0.0d0
REAL(dbl) :: vnhh(3,3) = 0.0d0
REAL(dbl) :: temph = 0.0d0 ! Thermostat temperature (from input)
REAL(dbl) :: fnoseh = 0.0d0 ! Thermostat frequency (from input)
REAL(dbl) :: qnh = 0.0d0 ! Thermostat mass (computed)
CONTAINS
subroutine cell_nose_init( temph_init, fnoseh_init )
USE constants, ONLY: factem, pi, terahertz
REAL(dbl), INTENT(IN) :: temph_init, fnoseh_init
! set thermostat parameter for cell
qnh = 0.0d0
temph = temph_init
fnoseh = fnoseh_init
if( fnoseh > 0.0d0 ) qnh = 2.d0 * ( 3 * 3 )*temph/factem/(fnoseh*(2.d0*pi)*terahertz)**2
return
end subroutine
subroutine cell_nosezero( vnhh, xnhh0, xnhhm )
real(dbl), intent(out) :: vnhh(3,3), xnhh0(3,3), xnhhm(3,3)
xnhh0=0.0d0
xnhhm=0.0d0
vnhh =0.0d0
return
end subroutine
subroutine cell_nosevel( vnhh, xnhh0, xnhhm, delt, velh, h, hold )
implicit none
real(kind=8), intent(inout) :: vnhh(3,3), velh(3,3)
real(kind=8), intent(in) :: xnhh0(3,3), xnhhm(3,3), delt, h(3,3), hold(3,3)
vnhh(:,:)=2.*(xnhh0(:,:)-xnhhm(:,:))/delt-vnhh(:,:)
velh(:,:)=2.*(h(:,:)-hold(:,:))/delt-velh(:,:)
return
end subroutine
subroutine cell_noseupd( xnhhp, xnhh0, xnhhm, delt, qnh, temphh, temph, vnhh )
use constants, only: factem
implicit none
real(kind=8), intent(out) :: xnhhp(3,3), vnhh(3,3)
real(kind=8), intent(in) :: xnhh0(3,3), xnhhm(3,3), delt, qnh, temphh(3,3), temph
integer :: i, j
do j=1,3
do i=1,3
xnhhp(i,j)=2.*xnhh0(i,j)-xnhhm(i,j)+ (delt**2/qnh)/factem*(temphh(i,j)-temph)
vnhh(i,j) =(xnhhp(i,j)-xnhhm(i,j))/( 2.0d0 * delt )
end do
end do
return
end subroutine
real(kind=8) function cell_nose_nrg( qnh, xnhh0, vnhh, temph, iforceh )
use constants, only: factem
implicit none
real(kind=8) :: qnh, vnhh( 3, 3 ), temph, xnhh0( 3, 3 )
integer :: iforceh( 3, 3 )
integer :: i, j
real(kind=8) :: enij
cell_nose_nrg = 0.0d0
do i=1,3
do j=1,3
enij = 0.5*qnh*vnhh(i,j)*vnhh(i,j)+temph/factem*xnhh0(i,j)
cell_nose_nrg = cell_nose_nrg + iforceh( i, j ) * enij
enddo
enddo
return
end function
subroutine cell_nose_shiftvar( xnhhp, xnhh0, xnhhm )
! shift values of nose variables to start a new step
implicit none
real(kind=8), intent(out) :: xnhhm(3,3)
real(kind=8), intent(inout) :: xnhh0(3,3)
real(kind=8), intent(in) :: xnhhp(3,3)
xnhhm = xnhh0
xnhh0 = xnhhp
return
end subroutine
!
!------------------------------------------------------------------------------!
END MODULE cell_nose
!------------------------------------------------------------------------------!