Line data    Source code

       1              : !!****m* ABINIT/m_gwls_GWanalyticPart
       2              : !! NAME
       3              : !! m_gwls_GWanalyticPart
       4              : !!
       5              : !! FUNCTION
       6              : !!  .
       7              : !!
       8              : !! COPYRIGHT
       9              : !! Copyright (C) 2009-2026 ABINIT group (JLJ, BR, MC)
      10              : !! This file is distributed under the terms of the
      11              : !! GNU General Public License, see ~abinit/COPYING
      12              : !! or http://www.gnu.org/copyleft/gpl.txt .
      13              : !!
      14              : !! SOURCE
      15              : 
      16              : #if defined HAVE_CONFIG_H
      17              : #include "config.h"
      18              : #endif
      19              : 
      20              : #include "abi_common.h"
      21              : 
      22              : 
      23              : module m_gwls_GWanalyticPart
      24              : !----------------------------------------------------------------------------------------------------
      25              : ! This module contains routines to compute the contribution to the GW correlation energy coming
      26              : ! from the analytic integral of the trial frequency function.
      27              : !----------------------------------------------------------------------------------------------------
      28              : ! local modules
      29              : use m_gwls_utility
      30              : use m_gwls_wf
      31              : use m_gwls_hamiltonian
      32              : use m_gwls_lineqsolver
      33              : use m_gwls_GWlanczos
      34              : use m_gwls_GenerateEpsilon
      35              : use m_gwls_LanczosBasis
      36              : use m_gwls_model_polarisability
      37              : use m_gwls_polarisability
      38              : !use m_gwls_ComplementSpacePolarizability
      39              : use m_gwls_GWlanczos
      40              : use m_gwls_TimingLog
      41              : 
      42              : ! abinit modules
      43              : use defs_basis
      44              : use m_abicore
      45              : 
      46              : implicit none
      47              : save
      48              : private
      49              : !!***
      50              : 
      51              : !real(dp),allocatable :: epsilon_eigenvalues_complement(:)
      52              : !real(dp),allocatable :: lanczos_basis_complement(:,:,:)
      53              : 
      54              : 
      55              : complex(dp),public, allocatable :: A_array(:,:)
      56              : 
      57              : integer, public  :: model_number
      58              : real(dp),public  :: model_parameter
      59              : 
      60              : real(dp), public :: G0_model_epsilon_0 ! model parameter
      61              : !!***
      62              : 
      63              : public :: get_projection_band_indices
      64              : !!***
      65              : 
      66              : contains
      67              : 
      68              : !!****f* m_hamiltonian/get_projection_band_indices
      69              : !! NAME
      70              : !!  get_projection_band_indices
      71              : !!
      72              : !! FUNCTION
      73              : !!  .
      74              : !!
      75              : !! INPUTS
      76              : !!
      77              : !! OUTPUT
      78              : !!
      79              : !! SOURCE
      80              : 
      81           65 : subroutine get_projection_band_indices(omega,band_index_below, band_index_above)
      82              : !----------------------------------------------------------------------------------------------------
      83              : ! This subroutine computes the band indices necessary for properly projecting the Sternheimer equations
      84              : ! where
      85              : !                Pe : projection on states such that epsilon_n < omega
      86              : !                Qe : projection on states such that epsilon_n > omega
      87              : !----------------------------------------------------------------------------------------------------
      88              : real(dp),intent(in)  :: omega
      89              : integer, intent(out) :: band_index_below, band_index_above
      90              : 
      91              : ! *************************************************************************
      92              : 
      93              : ! First, find the indices for the projections
      94              : 
      95           65 : band_index_below = 1
      96              : ! it is assumed that the eigenvalues are sorted. As soon as the current eigenvalue
      97              : ! is equal or larger than epsilon_e,  exit!
      98              : do
      99           65 : if ( omega - eig(band_index_below) <= 1.0e-8 ) exit
     100            0 : band_index_below = band_index_below + 1
     101              : 
     102           65 : if (band_index_below > size(eig)) then
     103              : 
     104            0 :   write(std_out,*) '************************************************************'
     105            0 :   write(std_out,*) '***    ERROR IN ROUTINE get_projection_band_indices      ***'
     106            0 :   write(std_out,*) '***                                                      ***'
     107            0 :   write(std_out,*) '***    The index of the DFT eigenvalue larger than       ***'
     108            0 :   write(std_out,*) '***    the target frequency is larger than the number    ***'
     109            0 :   write(std_out,*) '***    of explicitly calculated DFT eigenvalues.         ***'
     110            0 :   write(std_out,*) '***    The computation cannot go on to produce a         ***'
     111            0 :   write(std_out,*) '***    meaningful result: review your input!             ***'
     112            0 :   write(std_out,*) '***                                                      ***'
     113            0 :   write(std_out,*) '***               program stops.                         ***'
     114            0 :   write(std_out,*) '************************************************************'
     115            0 :   stop
     116              : end if
     117              : end do
     118              : ! We have overshooted in order to exit the do loop , so decrement by 1
     119           65 : band_index_below = band_index_below - 1
     120              : 
     121              : ! band_index_below  is now the index of the highest eigenvalue BELOW omega
     122              : ! NOTE THAT band_index_below = 0 if omega is smaller than all eigenvalues!
     123              : ! A test should be performed on the indices obtained from this routine
     124              : 
     125           65 : band_index_above = band_index_below+1
     126            0 : do
     127           65 : if ( eig(band_index_above)-omega > 1.0e-8 ) exit
     128            0 : band_index_above = band_index_above + 1
     129              : end do
     130              : ! band_index_above is now the index of the lowest eigenvalue ABOVE eig(e)
     131           65 : band_index_above = band_index_above - 1
     132              : ! band_index_above is now the highest index with eigenvalue equal to eig(e).
     133              : ! This is the correct index to remove the states with energy <= eig(e)
     134              : 
     135           65 : end subroutine get_projection_band_indices
     136              : !!***
     137              : 
     138              : end module m_gwls_GWanalyticPart
     139              : !!***