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canonical_configuration | add flag to displace imaginary modes #39

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canonical_configuration | add flag to displace imaginary modes
flokno Jan 19, 2024
a1047d0
Merge branch 'main' into fk_displace_imaginary_modes
mjv500 Jan 16, 2026
841f87b
Merge branch 'main' into fk_displace_imaginary_modes
mjv500 Jan 16, 2026
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4 changes: 2 additions & 2 deletions src/canonical_configuration/main.f90
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Original file line number Diff line number Diff line change
Expand Up @@ -188,9 +188,9 @@ program canonical_configuration
else
invert = .false.
end if
call fcss%initialize_cell(p, uc, fc, opts%temperature, opts%zpm, .false., opts%mindist, mw, imode=imode, invert=invert)
call fcss%initialize_cell(p, uc, fc, opts%temperature, opts%zpm, .false., opts%mindist, mw, imode=imode, invert=invert, imaginary=opts%imaginary)
else
call fcss%initialize_cell(p, uc, fc, opts%temperature, opts%zpm, .false., opts%mindist, mw)
call fcss%initialize_cell(p, uc, fc, opts%temperature, opts%zpm, .false., opts%mindist, mw, imaginary=opts%imaginary)
end if

! dump to file
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6 changes: 6 additions & 0 deletions src/canonical_configuration/options.f90
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Expand Up @@ -26,6 +26,7 @@ module options
real(r8) :: dielcutoff2 = -lo_huge
real(r8) :: dielcutoff3 = -lo_huge
logical :: modes = .false.
logical :: imaginary = .false.
contains
procedure :: parse
end type
Expand Down Expand Up @@ -118,6 +119,10 @@ subroutine parse(opts)
call cli%add(switch='--modes', &
help='Print displacements for every individual mode.', hidden=.true., &
required=.false., act='store_true', def='.false.', error=lo_status)
call cli%add(switch='--imaginary', hidden=.true., &
help='Displace imaginary modes as if they were positive', &
required=.false., act='store_true', def='.false.', error=lo_status)

if (lo_status .ne. 0) stop

cli_manpage
Expand Down Expand Up @@ -153,6 +158,7 @@ subroutine parse(opts)
call cli%get(switch='-dc2', val=opts%dielcutoff2)
call cli%get(switch='-dc3', val=opts%dielcutoff3)
call cli%get(switch='--modes', val=opts%modes)
call cli%get(switch='--imaginary', val=opts%imaginary)

! Convert input to atomic units right away
opts%maximum_frequency = opts%maximum_frequency*lo_frequency_THz_to_hartree
Expand Down
3 changes: 2 additions & 1 deletion src/libolle/type_forceconstant_secondorder.f90
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Expand Up @@ -196,7 +196,7 @@ module subroutine fake_forceconstant(fc, uc, ss, debye_temperature, maximum_freq
real(r8), intent(in), optional :: maximum_frequency
integer, intent(in), optional :: verbosity
end subroutine
module subroutine initialize_cell(fcss, ss, uc, fc, temperature, quantum, exact, closest_distance, mw, nosync, imode, invert)
module subroutine initialize_cell(fcss, ss, uc, fc, temperature, quantum, exact, closest_distance, mw, nosync, imode, invert, imaginary)
class(lo_forceconstant_secondorder), intent(inout) :: fcss
type(lo_crystalstructure), intent(inout) :: ss
type(lo_crystalstructure), intent(in) :: uc
Expand All @@ -209,6 +209,7 @@ module subroutine initialize_cell(fcss, ss, uc, fc, temperature, quantum, exact,
logical, intent(in), optional :: nosync
integer, intent(in), optional :: imode
logical, intent(in), optional :: invert
logical, intent(in), optional :: imaginary
end subroutine
module subroutine setsumtozero(fc)
class(lo_forceconstant_secondorder), intent(inout) :: fc
Expand Down
29 changes: 23 additions & 6 deletions src/libolle/type_forceconstant_secondorder_aux.f90
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Expand Up @@ -363,7 +363,7 @@ subroutine set_values(alpha, fc)
end subroutine

!> use the harmonic model to initialize a cell
module subroutine initialize_cell(fcss, ss, uc, fc, temperature, quantum, exact, closest_distance, mw, nosync, imode, invert)
module subroutine initialize_cell(fcss, ss, uc, fc, temperature, quantum, exact, closest_distance, mw, nosync, imode, invert, imaginary)
!> force constant for this (super) cell
class(lo_forceconstant_secondorder), intent(inout) :: fcss
!> supercell to be thermally populated
Expand All @@ -388,7 +388,10 @@ module subroutine initialize_cell(fcss, ss, uc, fc, temperature, quantum, exact,
integer, intent(in), optional :: imode
!> use negative mode amplitude so that u_i = \sum_s -Q_s X_si)
logical, intent(in), optional :: invert
!> displace imaginary modes instead of discarding
logical, intent(in), optional :: imaginary
real(r8) :: inv_prefactor
logical :: imaginary_

! Not sure about save attribute here.
type(lo_mersennetwister), save :: tw
Expand All @@ -402,6 +405,12 @@ module subroutine initialize_cell(fcss, ss, uc, fc, temperature, quantum, exact,
end if
end if

if (present(imaginary)) then
imaginary_ = imaginary
else
imaginary_ = .false.
end if

init: block
! Seed rng if needed
if (tw%initialized .eqv. .false.) then
Expand Down Expand Up @@ -435,13 +444,21 @@ module subroutine initialize_cell(fcss, ss, uc, fc, temperature, quantum, exact,
! Set the amplitudes
setamplitude: block
integer :: i
real(r8) :: omega_tmp

do i = 1, fcss%na*3
if (fcss%omega(i) .gt. lo_freqtol) then
if (imaginary_) then
! imaginary modes are supposed to be displaced instead of frozen
omega_tmp = abs(fcss%omega(i))
else
omega_tmp = fcss%omega(i)
end if
if (omega_tmp .gt. lo_freqtol) then
! Choose quantum or classical statistics
if (quantum) then
fcss%amplitudes(i) = sqrt((2*lo_planck(temperature, fcss%omega(i)) + 1)*0.5_r8/fcss%omega(i))
fcss%amplitudes(i) = sqrt((2*lo_planck(temperature, omega_tmp) + 1)*0.5_r8/omega_tmp)
else
fcss%amplitudes(i) = sqrt(lo_kb_hartree*temperature)/fcss%omega(i)
fcss%amplitudes(i) = sqrt(lo_kb_hartree*temperature)/omega_tmp
end if
else
! set to zero for acoustic modes
Expand Down Expand Up @@ -474,7 +491,7 @@ module subroutine initialize_cell(fcss, ss, uc, fc, temperature, quantum, exact,
do j = 1, 3
l = l + 1
ss%u(j, a1) = +fcss%amplitudes(imode)*ss%invsqrtmass(a1)*fcss%eigenvectors(l, imode)
ss%v(j, a1) = -fcss%amplitudes(imode)*ss%invsqrtmass(a1)*fcss%eigenvectors(l, imode)*fcss%omega(imode)
ss%v(j, a1) = -fcss%amplitudes(imode)*ss%invsqrtmass(a1)*fcss%eigenvectors(l, imode)*abs(fcss%omega(imode))
end do
end do
else
Expand All @@ -487,7 +504,7 @@ module subroutine initialize_cell(fcss, ss, uc, fc, temperature, quantum, exact,
do j = 1, 3
l = l + 1
ss%u(j, a1) = ss%u(j, a1) + fcss%amplitudes(i)*ss%invsqrtmass(a1)*x1*fcss%eigenvectors(l, i)
ss%v(j, a1) = ss%v(j, a1) - fcss%amplitudes(i)*ss%invsqrtmass(a1)*x2*fcss%eigenvectors(l, i)*fcss%omega(i)
ss%v(j, a1) = ss%v(j, a1) - fcss%amplitudes(i)*ss%invsqrtmass(a1)*x2*fcss%eigenvectors(l, i)*abs(fcss%omega(i))
end do
end do
end do modeloop
Expand Down