!------------------------------------------------------------------------------------
!> Summary:Spin mixing for non-collinear magnetic moments
!> Author: Philipp Ruessmann
!> See also mixbroydenspin of impurity code for reference to broyden spin mixing
!------------------------------------------------------------------------------------
module mod_mixnocospin
private
public :: spinmix_noco
contains
!-------------------------------------------------------------------------------
!> Summary: Wrapper for spin miging of nonco angles
!> Author: Philipp Ruessmann
!> Category: KKRhost
!> Deprecated: False
!> Perform spin mixing of nonco angles either with setting output angles to new input
!> (this is the default behavior) or do broyden mixing for the nonco moments to get
!> the new directions.
!-------------------------------------------------------------------------------
subroutine spinmix_noco(iter, natyp, theta, phi, fixdir, angles_new, totmoment, iounit)
use mod_datatypes, only: dp
use mod_constants, only: pi
use mod_runoptions, only: use_broyden_spinmix, write_angles_alliter, disable_print_serialnumber, fix_nonco_angles, decouple_spins_cheby
use global_variables, only: qbound_spin
use mod_version_info, only: version_print_header
use mod_wunfiles, only: t_params
implicit none
! interface
integer, intent(in) :: iter !! iteration counter
integer, intent(in) :: natyp !! number of atoms (array dimensions)
real (kind=dp), dimension (natyp), intent(in) :: theta !! theta nonco angles in rad
real (kind=dp), dimension (natyp), intent(in) :: phi !! phi nonco angles in rad
logical, dimension(natyp), intent(in) :: fixdir !! booleans to fix nocon angles
real (kind=dp), intent(in) :: totmoment(natyp) !! length of the magentization vectors
real (kind=dp), intent(in) :: angles_new(2, natyp) !! new directions of the nonco angles
integer, intent(in) :: iounit !! output unit where the nonco_angles output file is written
! local
integer :: i1 !! atom index
real (kind=dp) :: diff_phi !! for difference in phi nonco angles
real (kind=dp), dimension (natyp) :: diff_angles_sq !! squared difference in nonco angles in rad
logical :: all_fixed !! True if all nonco angles are fixed
! MdSD,PR: write information on new angles to output file
if (.not.decouple_spins_cheby) then
write (1337,*)
write (1337, '(" I1 In/Out THETA[deg] In/Out PHI[deg] FIXDIR[boolean] RMS(angles)[deg]")')
do i1 = 1, natyp
if (.not.fixdir(i1)) then
! renormalize to difference in phi in range [0,180]
diff_phi = phi(i1) - angles_new(2, i1)
if (diff_phi>pi) diff_phi = diff_phi - pi
! now compute squared difference of the angles
diff_angles_sq(i1) = (theta(i1)-angles_new(1, i1))**2 + diff_phi**2
else
diff_angles_sq(i1) = 0.0_dp
end if
write (1337, '(I8,4F12.6,3x,1L,17x,1F12.6)') i1, theta(i1)*180.0_dp/pi, angles_new(1, i1)/pi*180.0_dp, &
phi(i1)*180.0_dp/pi, angles_new(2, i1)/pi*180.0_dp, fixdir(i1), sqrt(diff_angles_sq(i1))/pi*180.0_dp
if (i1==1) all_fixed = .true. ! initialize
if(.not.fixdir(i1)) all_fixed = .false. ! if at least one is not fixed we set this to False
end do ! i1
write (1337, '(A, 1F12.6)') "Total RMS(angles) [deg]:", sqrt(sum(diff_angles_sq))/pi*180.0_dp
! write also to std out
write (*, '(A, 1F12.6)') "Total RMS(angles) [deg]:", sqrt(sum(diff_angles_sq))/pi*180.0_dp
! check if all angles should be fixed (see SPINMIXQBOUND input parameter)
if ((.not.all_fixed) .and. sqrt(sum(diff_angles_sq))/pi*180.0_dp < qbound_spin) then
write(*,*) 'TOTAL RMS(angles) < qbound_spin:', sqrt(sum(diff_angles_sq))/pi*180.0_dp, qbound_spin
write(*,*) 'Fix all angles from now on'
do i1 = 1, natyp
t_params%fixdir(i1) = .true.
end do
end if
end if ! .not.decouple_spins_cheby
! rewrite new theta and phi to nonco_angle_out.dat, nonco_angle.dat is the input
if (.not. fix_nonco_angles) then
! open nocno_angles files
open (unit=iounit, file='nonco_angle_out.dat', form='formatted')
call version_print_header(iounit, disable_print=disable_print_serialnumber)
if (write_angles_alliter) open(unit=iounit+1, file='nonco_angle_out_all_iter.dat', form='formatted', position='append')
if (.not.use_broyden_spinmix) then
! conventional scheme: use output angles as input
do i1 = 1, natyp
! save to file in converted units (degrees)
if (t_params%fixdir(i1)) then
! keep the old angles
write (iounit, *) t_params%theta(i1)/pi*180.0_dp, t_params%phi(i1)/pi*180.0_dp, t_params%fixdir(i1)
else
! update angles
write (iounit, *) angles_new(1, i1)/pi*180.0_dp, angles_new(2, i1)/pi*180.0_dp, t_params%fixdir(i1)
! use internal units here
t_params%theta(i1) = angles_new(1, i1)
t_params%phi(i1) = angles_new(2, i1)
end if
if (write_angles_alliter) write (iounit+1, *) t_params%theta(i1)/pi*180.0_dp, t_params%phi(i1)/pi*180.0_dp, t_params%fixdir(i1)
end do
else ! use_broyden_spinmix
! use spin moxing as in impurity code
call spinmix_broyden(iter, natyp, angles_new, totmoment, iounit)
end if ! use_broyden_spinmix
! close output noco_angles files
close (iounit)
if (write_angles_alliter) close(iounit+1)
end if ! .not.fix_nonco_angles
end subroutine spinmix_noco
!-------------------------------------------------------------------------------
!> Summary: Do Broyden spin mixing for noncollinear magnetic moment directions
!> Author: Philipp Ruessmann
!> Category: KKRhost
!> Deprecated: False
!> Perform spin mixing of nonco angles by first creating magentization vectors
!> that are then mixed (should be more stable than mixing the angles directly)
!-------------------------------------------------------------------------------
subroutine spinmix_broyden(iter, natyp, angles_new, totmoment_atoms, iounit)
use mod_datatypes, only: dp
use mod_constants, only: pi
use mod_wunfiles, only: t_params
use global_variables, only: mixfac_broydenspin, ninit_broydenspin, memlen_broydenspin
use mod_runoptions, only: write_angles_alliter
use mod_broyden, only: broyden
implicit none
! interface
integer, intent(in) :: iter !! iteration counter
integer, intent(in) :: natyp !! number of atoms (array dimensions)
real (kind=dp), intent(in) :: angles_new(2, natyp) !! new directions of the nonco angles
real (kind=dp), intent(in) :: totmoment_atoms(natyp) !! length of the magentization vectors
integer, intent(in) :: iounit !! output unit where the nonco_angles output file is written
! local
real (kind=dp), parameter :: tol = 1.0e-12_dp !! MdSD: shifting problems with Broyden to the future
integer :: nfixed !! number of fixed angles
integer :: ipos !! for loop indices etc.
integer :: vlen !! length of vector
real (kind=dp), allocatable :: vector(:, :) !! magnetization directions (first index=1 is old values, =2 is new values)
real (kind=dp) :: rms, moment(3), totmoment, totxymoment, theta, phi, alpha
integer :: i1
! get number of fixed angles (we need to use the rest only for the mixing)
nfixed = 0
do i1 = 1, natyp
if (t_params%fixdir(i1)) nfixed = nfixed + 1
end do
! allocate working arrays
vlen = 3*(natyp-nfixed)
allocate(vector(vlen, 2), stat=ipos)
if (ipos>0) stop 'Error allocating vector in spinmix_broyden'
vector(:,:) = 0.0_dp
! convert angles to magnetization direction vectors
ipos = 0
do i1 = 1, natyp
if (.not. t_params%fixdir(i1)) then
! we use the same vector length (i.e. the output length since we can assume that it will not change much)
! set old vector
theta = t_params%theta(i1)
phi = t_params%phi(i1)
vector(1+ipos*3, 1) = totmoment_atoms(i1)*cos(phi)*sin(theta)
vector(2+ipos*3, 1) = totmoment_atoms(i1)*sin(phi)*sin(theta)
vector(3+ipos*3, 1) = totmoment_atoms(i1)*cos(theta)
! new vector
theta = angles_new(1, i1)
phi = angles_new(2, i1)
vector(1+ipos*3, 2) = totmoment_atoms(i1)*cos(phi)*sin(theta)
vector(2+ipos*3, 2) = totmoment_atoms(i1)*sin(phi)*sin(theta)
vector(3+ipos*3, 2) = totmoment_atoms(i1)*cos(theta)
! update loop counter
ipos = ipos + 1
end if ! fixdir
end do
! find rms value
rms = 0.0_dp
do ipos = 1, vlen
rms = rms + (vector(ipos,2) - vector(ipos,1))**2
end do
rms = sqrt(rms)
! different alpha for simple mixing and broyden mixing steps
alpha = mixfac_broydenspin
if (iter<=ninit_broydenspin) alpha = 1.0_dp ! always use alpha=1 for simple mixing steps
! MdSD: there are special high-symmetry situations where the rms for the angles is zero
! MdSD: linear mixing is fine with that, but if broyden is called it will cause a NaN
! MdSD: this line delays using Broyden
if (rms < tol .and. iter == ninit_broydenspin) ninit_broydenspin = ninit_broydenspin + 1
! now do Broyden mixing
call broyden (vector, vlen, alpha, rms, iter, &
ninit_broydenspin, memlen_broydenspin, vlen)
! output
ipos = 0
do i1 = 1, natyp
if (.not. t_params%fixdir(i1)) then
! transform back to angles (vector(:,2) now is the output direction vector)
moment(1) = vector(1+3*ipos, 2)
moment(2) = vector(2+3*ipos, 2)
moment(3) = vector(3+3*ipos, 2)
totmoment = sqrt(moment(1)**2+moment(2)**2+moment(3)**2)
totxymoment = sqrt(moment(1)**2+moment(2)**2)
! theta not 0 or pi
if (abs(totxymoment)>1d-05) then
theta = acos(moment(3)/totmoment)
phi = atan2(moment(2), moment(1))
! theta is 0 or pi
else
if (moment(3) < 0.0_dp .and. abs(moment(3)) > 1e-14_dp) then
theta = pi
else
theta = 0.0_dp
end if
phi = 0.0_dp
end if
! now set mixed angles as output
t_params%theta(i1) = theta
t_params%phi(i1) = phi
! update loop counter
ipos = ipos + 1
end if ! fixdir
! write output nonco angles file
write (iounit, *) t_params%theta(i1)/pi*180.0_dp, t_params%phi(i1)/pi*180.0_dp, t_params%fixdir(i1)
if (write_angles_alliter) write (iounit+1, *) t_params%theta(i1)/pi*180.0_dp, t_params%phi(i1)/pi*180.0_dp, t_params%fixdir(i1)
end do
! cleanup allocations of working arrays
deallocate(vector, stat=ipos)
end subroutine spinmix_broyden
end module mod_mixnocospin