mirror of https://gitlab.com/QEF/q-e.git
115 lines
3.4 KiB
Fortran
115 lines
3.4 KiB
Fortran
!
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! Copyright (C) 2001 PWSCF group
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! This file is distributed under the terms of the
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! GNU General Public License. See the file `License'
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! in the root directory of the present distribution,
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! or http://www.gnu.org/copyleft/gpl.txt .
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!
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!-----------------------------------------------------------------------
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subroutine dyndia (xq, nmodes, nat, ntyp, ityp, amass, iudyn, dyn, w2)
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!-----------------------------------------------------------------------
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!
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! This routine diagonalizes the dynamical matrix and returns
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! displacement patterns in "dyn". The frequencies are written
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! on output from this routine.
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!
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!
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#include "f_defs.h"
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USE io_global, ONLY : stdout
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USE kinds, only : DP
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implicit none
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!
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! first the dummy variables
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!
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integer :: nmodes, nat, ntyp, ityp (nat), iudyn
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! input: the total number of modes
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! input: the number of atoms
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! input: the number of types
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! input: the types of atoms
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! input: the unit with the dynamical matrix
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real(DP) :: xq (3), amass (ntyp), w2 (3 * nat)
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! input: q vector
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! input: the masses
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! output: the frequencies squared
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complex(DP) :: dyn (3 * nat, nmodes)
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! input: the dynamical matrix
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!
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! here the local variables
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!
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integer :: nta, ntb, nu_i, nu_j, mu, na, nb, i
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! counters
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real(DP) :: rydthz, rydcm1, w1, unorm
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! conversion from a.u. to terahertz
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! conversion from a.u. to cm^-1
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! the frequency
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! norm of u
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complex(DP) :: z (3 * nat, 3 * nat)
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! the eigenvectors
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!
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! fill the second half of the matrix (imposing hermiticity !)
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!
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do nu_i = 1, nmodes
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do nu_j = 1, nu_i
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dyn (nu_i, nu_j) = 0.5d0 * (dyn (nu_i, nu_j) + &
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CONJG(dyn (nu_j, nu_i) ) )
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dyn (nu_j, nu_i) = CONJG(dyn (nu_i, nu_j) )
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enddo
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enddo
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!
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! divide the dynamical matrix by the masses
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!
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do nu_i = 1, nmodes
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na = (nu_i - 1) / 3 + 1
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nta = ityp (na)
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do nu_j = 1, nmodes
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nb = (nu_j - 1) / 3 + 1
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ntb = ityp (nb)
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dyn (nu_i, nu_j) = dyn (nu_i, nu_j) / sqrt (amass (nta) * amass (ntb) )
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enddo
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enddo
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!
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! solve the eigenvalue problem
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!
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call cdiagh (nmodes, dyn, 3 * nat, w2, z)
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!
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! conversion factors ryd=>thz e ryd=>1/cm
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!
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rydthz = 13.6058d0 * 241.796d0
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rydcm1 = 13.6058d0 * 8065.5d0
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!
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! Writes on output the displacements and the normalized frequencies.
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!
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WRITE( stdout, 9000) (xq (i), i = 1, 3)
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if (iudyn /= 0) write (iudyn, 9000) (xq (i), i = 1, 3)
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9000 format(/,5x,'Diagonalizing the dynamical matrix', &
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& //,5x,'q = ( ',3f14.9,' ) ',//,1x,74('*'))
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dyn (:,:) = (0.d0, 0.d0)
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do nu_i = 1, nmodes
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w1 = sqrt (abs (w2 (nu_i) ) )
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if (w2 (nu_i) < 0.d0) w1 = - w1
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WRITE( stdout, 9010) nu_i, w1 * rydthz, w1 * rydcm1
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if (iudyn /= 0) write (iudyn, 9010) nu_i, w1 * rydthz, w1 * rydcm1
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9010 format (5x,'omega(',i2,') =',f15.6,' [THz] =',f15.6,' [cm-1]')
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!
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! write displacements onto matrix dyn
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!
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unorm = 0.d0
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do mu = 1, 3 * nat
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na = (mu - 1) / 3 + 1
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dyn (mu, nu_i) = z (mu, nu_i) / sqrt (amass (ityp (na) ) )
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unorm = unorm + dyn (mu, nu_i) * CONJG(dyn (mu, nu_i) )
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enddo
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if (iudyn /= 0) write (iudyn, '(" (",6f10.6," ) ")') &
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(dyn (mu, nu_i) / sqrt (unorm) , mu = 1, 3 * nat)
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enddo
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WRITE( stdout, '(1x,74("*"))')
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if (iudyn /= 0) write (iudyn, '(1x,74("*"))')
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return
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end subroutine dyndia
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