quantum-espresso/PHonon/Gamma/dyndiar.f90

111 lines
3.2 KiB
Fortran

!
! Copyright (C) 2003 PWSCF 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 .
!
!
!-----------------------------------------------------------------------
SUBROUTINE dyndiar (dyn,nat3,nmodes,u,nat,ityp,amass,w2,dynout)
!-----------------------------------------------------------------------
!
! diagonalizes the dynamical matrix "dyn", returns energies in "w2"
! and mode displacements in "dynout". dyn is unchanged on output.
!
USE kinds, ONLY : DP
USE constants, ONLY : amu_ry, ry_to_thz, ry_to_cmm1
USE io_global, ONLY : stdout
USE mp_bands, ONLY : me_bgrp, root_bgrp, intra_bgrp_comm
IMPLICIT NONE
include 'laxlib.fh'
INTEGER :: nmodes, nat3, nat,ityp(nat), iudyn
real(DP):: dyn(nat3,nmodes), u(nat3,nmodes), amass(*)
real(DP):: dynout(nat3,nmodes), w2(nat3)
!
INTEGER:: nu_i, nu_j, mu, na, nb, nt, i, j
real(DP), ALLOCATABLE :: m(:,:), z(:,:)
real(DP) :: w1, unorm, sum, dif
!
ALLOCATE ( m ( nat3, nat3))
ALLOCATE ( z ( nat3, nat3))
!
CALL dcopy(nat3*nmodes,dyn,1,dynout,1)
!
! Impose symmetry to the matrix
!
dif=0.d0
DO nu_i=1,nmodes
DO nu_j=1,nu_i-1
dif = dif + abs(dynout(nu_i,nu_j)-dynout(nu_j,nu_i))
dynout(nu_j,nu_i) = 0.5d0*(dynout(nu_i,nu_j)+dynout(nu_j,nu_i))
dynout(nu_i,nu_j) = dynout(nu_j,nu_i)
ENDDO
ENDDO
WRITE( stdout,9000) dif
!
! Impose Acoustic Sum Rule
!
dif=0.d0
DO i=1,3
DO j=1,3
DO na=1,nat
sum=0.d0
DO nb=1,nat
IF (na/=nb) sum=sum+dynout((na-1)*3+i,(nb-1)*3+j)
ENDDO
dif = dif + abs(dynout((na-1)*3+i,(na-1)*3+j) + sum)
dynout((na-1)*3+i,(na-1)*3+j) = -sum
ENDDO
ENDDO
ENDDO
WRITE( stdout,9005) dif
!
! fill the mass matrix (masses are in amu, amu_ry converts to a.u.)
!
DO nu_i = 1,nmodes
DO nu_j = 1,nmodes
m(nu_i,nu_j) = 0.0d0
DO mu = 1,3*nat
na = (mu-1)/3+1
nt = ityp(na)
m(nu_i,nu_j) = m(nu_i,nu_j) + amu_ry*amass(nt)*u(mu,nu_i)*u(mu,nu_j)
ENDDO
ENDDO
ENDDO
!
! solve the generalized eigenvalue problem w2*(M*z) = (Cz)
! Note that z are eigendisplacements in the base of input
! modes u and that they are normalized as <z|M|z>=I
!
CALL diaghg (nat3, nmodes, dynout, m, nat3, w2, z, me_bgrp, root_bgrp, intra_bgrp_comm)
!
! write frequencies
!
WRITE( stdout,'(5x,"diagonalizing the dynamical matrix ..."//)')
WRITE( stdout,'(1x,74("*"))')
!
dynout (:,:) = 0.0d0
DO nu_i = 1,nmodes
w1 = sqrt(abs(w2(nu_i)))
IF (w2(nu_i)<0.0) w1 = -w1
WRITE( stdout,9010) nu_i, w1*ry_to_thz, w1*ry_to_cmm1
! bring eigendisplacements in cartesian axis
DO mu = 1,3*nat
DO i = 1,nmodes
dynout(mu,nu_i) = dynout(mu,nu_i) + z(i,nu_i)*u(mu,i)
ENDDO
ENDDO
ENDDO
WRITE( stdout,'(1x,74("*"))')
!
DEALLOCATE(z)
DEALLOCATE(m)
RETURN
!
9000 FORMAT (' Symmetry violation sum_ij |D_ij-D_ji| :',f15.6)
9005 FORMAT (' ASR violation sum_i |D_ij| :',f15.6)
9010 FORMAT(5x,'omega(',i3,') =',f10.6,' [THz] =',f11.6,' [cm-1]')
!
END SUBROUTINE dyndiar