121 lines
3.7 KiB
Fortran
121 lines
3.7 KiB
Fortran
! Agreement with the model: Rho
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! *Compute the ratio : rho = (prev_energy - energy) / (prev_energy - e_model)*
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! Rho represents the agreement between the model (the predicted energy
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! by the Taylor expansion truncated at the 2nd order) and the real
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! energy :
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! \begin{equation}
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! \rho^{k+1} = \frac{E^{k} - E^{k+1}}{E^{k} - m^{k+1}}
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! \end{equation}
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! With :
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! $E^{k}$ the energy at the previous iteration
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! $E^{k+1}$ the energy at the actual iteration
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! $m^{k+1}$ the predicted energy for the actual iteration
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! (cf. trust_e_model)
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! If $\rho \approx 1$, the agreement is good, contrary to $\rho \approx 0$.
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! If $\rho \leq 0$ the previous energy is lower than the actual
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! energy. We have to cancel the last step and use a smaller trust
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! region.
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! Here we cancel the last step if $\rho < 0.1$, because even if
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! the energy decreases, the agreement is bad, i.e., the Taylor expansion
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! truncated at the second order doesn't represent correctly the energy
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! landscape. So it's better to cancel the step and restart with a
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! smaller trust region.
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! Provided in qp_edit:
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! | thresh_rho |
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! Input:
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! | prev_energy | double precision | previous energy (energy before the rotation) |
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! | e_model | double precision | predicted energy after the rotation |
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! Output:
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! | rho | double precision | the agreement between the model (predicted) and the real energy |
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! | prev_energy | double precision | if rho >= 0.1 the actual energy becomes the previous energy |
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! | | | else the previous energy doesn't change |
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! Internal:
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! | energy | double precision | energy (real) after the rotation |
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! | i | integer | index |
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! | t* | double precision | time |
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subroutine trust_region_rho(prev_energy, energy,e_model,rho)
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include 'pi.h'
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!BEGIN_DOC
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! Compute rho, the agreement between the predicted criterion/energy and the real one
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!END_DOC
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implicit none
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! Variables
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! In
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double precision, intent(inout) :: prev_energy
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double precision, intent(in) :: e_model, energy
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! Out
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double precision, intent(out) :: rho
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! Internal
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double precision :: t1, t2, t3
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integer :: i
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print*,''
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print*,'---Rho_model---'
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!call wall_time(t1)
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! Rho
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! \begin{equation}
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! \rho^{k+1} = \frac{E^{k} - E^{k+1}}{E^{k} - m^{k+1}}
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! \end{equation}
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! In function of $\rho$ th step can be accepted or cancelled.
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! If we cancel the last step (k+1), the previous energy (k) doesn't
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! change!
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! If the step (k+1) is accepted, then the "previous energy" becomes E(k+1)
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! Already done in an other subroutine
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!if (ABS(prev_energy - e_model) < 1d-12) then
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! print*,'WARNING: prev_energy - e_model < 1d-12'
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! print*,'=> rho will tend toward infinity'
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! print*,'Check you convergence criterion !'
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!endif
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rho = (prev_energy - energy) / (prev_energy - e_model)
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!print*, 'previous energy, prev_energy:', prev_energy
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!print*, 'predicted energy, e_model:', e_model
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!print*, 'real energy, energy:', energy
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!print*, 'prev_energy - energy:', prev_energy - energy
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!print*, 'prev_energy - e_model:', prev_energy - e_model
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print*, 'Rho:', rho
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!print*, 'Threshold for rho:', thresh_rho
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! Modification of prev_energy in function of rho
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if (rho < thresh_rho) then !0.1) then
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! the step is cancelled
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print*, 'Rho <', thresh_rho,', the previous energy does not changed'
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!print*, 'prev_energy :', prev_energy
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else
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! the step is accepted
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prev_energy = energy
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print*, 'Rho >=', thresh_rho,', energy -> prev_energy:', energy
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endif
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!call wall_time(t2)
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!t3 = t2 - t1
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!print*,'Time in rho model:', t3
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print*,'---End rho_model---'
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end subroutine
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