TABLE OF CONTENTS

ABINIT/m_gwls_GWanalyticPart [ Modules ]

[ Top ] [ Modules ]

NAME

 m_gwls_GWanalyticPart

FUNCTION

  .

COPYRIGHT

 Copyright (C) 2009-2024 ABINIT group (JLJ, BR, MC)
 This file is distributed under the terms of the
 GNU General Public License, see ~abinit/COPYING
 or http://www.gnu.org/copyleft/gpl.txt .

SOURCE

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

m_hamiltonian/get_projection_band_indices [ Functions ]

[ Top ] [ m_hamiltonian ] [ Functions ]

NAME

  get_projection_band_indices

FUNCTION

  .

INPUTS

OUTPUT

SOURCE

 81 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 implicit none
 89 
 90 real(dp),intent(in)  :: omega 
 91 integer, intent(out) :: band_index_below, band_index_above
 92 
 93 ! *************************************************************************
 94 
 95 ! First, find the indices for the projections
 96 
 97 band_index_below = 1
 98 ! it is assumed that the eigenvalues are sorted. As soon as the current eigenvalue
 99 ! is equal or larger than epsilon_e,  exit!
100 do
101 if ( omega - eig(band_index_below) <= 1.0e-8 ) exit
102 band_index_below = band_index_below + 1
103 
104 if (band_index_below > size(eig)) then
105 
106   write(std_out,*) '************************************************************'
107   write(std_out,*) '***    ERROR IN ROUTINE get_projection_band_indices      ***'
108   write(std_out,*) '***                                                      ***'
109   write(std_out,*) '***    The index of the DFT eigenvalue larger than       ***'
110   write(std_out,*) '***    the target frequency is larger than the number    ***'
111   write(std_out,*) '***    of explicitly calculated DFT eigenvalues.         ***'
112   write(std_out,*) '***    The computation cannot go on to produce a         ***'
113   write(std_out,*) '***    meaningful result: review your input!             ***'
114   write(std_out,*) '***                                                      ***'
115   write(std_out,*) '***               program stops.                         ***'
116   write(std_out,*) '************************************************************'
117   stop
118 end if
119 end do
120 ! We have overshooted in order to exit the do loop , so decrement by 1
121 band_index_below = band_index_below - 1
122 
123 ! band_index_below  is now the index of the highest eigenvalue BELOW omega
124 ! NOTE THAT band_index_below = 0 if omega is smaller than all eigenvalues!
125 ! A test should be performed on the indices obtained from this routine
126 
127 band_index_above = band_index_below+1
128 do
129 if ( eig(band_index_above)-omega > 1.0e-8 ) exit
130 band_index_above = band_index_above + 1
131 end do
132 ! band_index_above is now the index of the lowest eigenvalue ABOVE eig(e)
133 band_index_above = band_index_above - 1
134 ! band_index_above is now the highest index with eigenvalue equal to eig(e).
135 ! This is the correct index to remove the states with energy <= eig(e)
136 
137 end subroutine get_projection_band_indices