mirror of https://gitlab.com/QEF/q-e.git
168 lines
7.2 KiB
Fortran
168 lines
7.2 KiB
Fortran
!
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! Copyright (C) 2015-2016 Aihui Zhou's group
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!
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! This file is distributed under the terms of the
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! GNU General Public License. See the file `License'
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! in the root directory of the present distribution,
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! or http://www.gnu.org/copyleft/gpl.txt .
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!
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!-------------------------------------------------------------------------------
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!
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! We propose some parallel orbital updating based plane wave basis methods
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! for electronic structure calculations, which aims to the solution of the corresponding eigenvalue
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! problems. Compared to the traditional plane wave methods, our methods have the feature of two level
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! parallelization, which make them have great advantage in large-scale parallelization.
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!
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! The approach following Algorithm is the parallel orbital updating algorithm:
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! 1. Choose initial $E_{\mathrm{cut}}^{(0)}$ and then obtain $V_{N_G^{0}}$, use the SCF method to solve
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! the Kohn-Sham equation in $V_{G_0}$ and get the initial $(\lambda_i^{0},u_i^{0}), i=1, \cdots, N$
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! and let $n=0$.
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! 2. For $i=1,2,\ldots,N$, find $e_i^{n+1/2}\in V_{G_n}$ satisfying
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! $$a(\rho_{in}^{n}; e_i^{n+1/2}, v) = -[(a(\rho_{in}^{n}; u_i^{n}, v) - \lambda_i^{n} (u_i^{n}, v))] $$
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! in parallel , where $\rho_{in}^{n}$ is the input charge density obtained by the orbits obtained in the
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! $n$-th iteration or the former iterations.
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! 3. Find $\{\lambda_i^{n+1},u_i^{n+1}\} \in \mathbf{R}\times \tilde{V}_N$ satisfying
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! $$a(\tilde{\rho}; u_i^{n+1}, v) = ( \lambda_i^{n+1}u_i^{n+1}, v) \quad \forall v \in \tilde{V}_N$$
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! where $\tilde{V}_N = \mathrm{span}\{e_1^{n+1/2},\ldots,e_N^{n+1/2},u_1^{n},\ldots,u_N^{n}\}$,
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! $\tilde{\rho}(x)$ is the input charge density obtained from the previous orbits.
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! 4. Convergence check: if not converged, set $n=n+1$, go to step 2; else, stop.
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!
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! You can see the detailed information through
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! X. Dai, X. Gong, A. Zhou, J. Zhu,
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! A parallel orbital-updating approach for electronic structure calculations, arXiv:1405.0260 (2014).
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! X. Dai, Z. Liu, X. Zhang, A. Zhou,
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! A Parallel Orbital-updating Based Optimization Method for Electronic Structure Calculations,
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! arXiv:1510.07230 (2015).
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! Yan Pan, Xiaoying Dai, Xingao Gong, Stefano de Gironcoli, Gian-Marco Rignanese, and Aihui Zhou,
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! A Parallel Orbital-updating Based Plane Wave Basis Method. J. Comp. Phys. 348, 482-492 (2017).
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!
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! The file is written mainly by Stefano de Gironcoli and Yan Pan.
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!
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!-------------------------------------------------------------------------------
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SUBROUTINE paro_gamma( h_psi_ptr, s_psi_ptr, hs_1psi_ptr, g_1psi_ptr, overlap, &
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npwx, npw, nbnd, evc, eig, btype, ethr, notconv, nhpsi )
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!-------------------------------------------------------------------------------
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!paro_flag = 1: modified parallel orbital-updating method
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! global variables
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USE util_param, ONLY : DP, stdout
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USE mp_bands_util, ONLY : my_bgrp_id, inter_bgrp_comm
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USE mp, ONLY : mp_sum
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IMPLICIT NONE
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!
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INCLUDE 'laxlib.fh'
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! I/O variables
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LOGICAL, INTENT(IN) :: overlap
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INTEGER, INTENT(IN) :: npw, npwx, nbnd
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COMPLEX(DP), INTENT(INOUT) :: evc(npwx,nbnd)
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REAL(DP), INTENT(IN) :: ethr
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REAL(DP), INTENT(INOUT) :: eig(nbnd)
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INTEGER, INTENT(IN) :: btype(nbnd)
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INTEGER, INTENT(OUT) :: notconv, nhpsi
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! INTEGER, INTENT(IN) :: paro_flag
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! local variables (used in the call to cegterg )
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!------------------------------------------------------------------------
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EXTERNAL h_psi_ptr, s_psi_ptr, hs_1psi_ptr, g_1psi_ptr
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! subroutine h_psi_ptr (npwx,npw,nvec,evc,hpsi) computes H*evc using band parallelization
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! subroutine s_psi_ptr (npwx,npw,nvec,evc,spsi) computes S*evc using band parallelization
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! subroutine hs_1psi_ptr(npwx,npw,evc,hpsi,spsi) computes H*evc and S*evc for a single band
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! subroutine g_1psi_ptr (npwx,npw,psi,eig) computes g*psi for a single band
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!
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! ... local variables
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!
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INTEGER :: iter, itry, paro_ntr, nconv, nextra, nactive, nbase, ndiag, nproc_ortho
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REAL(DP), ALLOCATABLE :: ew(:)
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COMPLEX(DP), ALLOCATABLE :: psi2(:,:)
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LOGICAL, ALLOCATABLE :: conv(:)
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INTEGER :: ibnd, ibnd_start, ibnd_end, lbnd
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!
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! ... init local variables
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!
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CALL laxlib_getval( nproc_ortho = nproc_ortho )
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iter = 0
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nhpsi = 0
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paro_ntr = 20
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!
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! write (6,*) ' paro_flag = ', paro_flag
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! if (paro_flag /= 1) WRITE(stdout,*) 'wrong setting of paro_flag!! '
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ALLOCATE ( psi2(npwx,2*nbnd), ew(2*nbnd), conv(nbnd) )
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conv(:) = .FALSE. ; nconv = COUNT ( conv(:) )
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psi2(:,1:nbnd) = evc(:,1:nbnd) ! copy input evc into work vector
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ew(1:nbnd) = eig(1:nbnd) ! copy input eigenvalues into work vector
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ParO_loop : &
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DO itry = 1,paro_ntr
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!write (6,*) ' paro_itry =', itry, ethr
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nactive = nbnd - (nconv+1)/2 ! number of correction vectors to be computed (<nbnd)
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notconv = nbnd - nconv ! number of needed roots
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nextra = nactive - notconv ! number of extra vectors
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nbase = nconv + nactive ! number of orbitals the correction should be orthogonal to (<2*nbnd)
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ndiag = nbase + nactive ! dimension of the matrix to be diagonalized at this iteration (<2*nbnd)
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!write (*,*) itry, notconv, conv
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!write (6,*) ' nbnd, nconv, notconv, nextra, nactive, nbase, ndiag =', nbnd, nconv, notconv, nextra, nactive, nbase, ndiag
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call s_psi_ptr (npwx,npw,nbnd,psi2,evc) ! computes S*psi needed to ortogonalize to nbase
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lbnd = nbase
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DO ibnd = 1, nbnd ! pack unconverged roots
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IF (.NOT.conv(ibnd) ) THEN
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lbnd = lbnd+1
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psi2(:,lbnd) = psi2(:,ibnd)
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eig(lbnd-nbase) = ew(ibnd)
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END IF
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END DO
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DO ibnd = nbnd+1, nbase
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lbnd = lbnd + 1
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psi2(:,lbnd) = psi2(:,ibnd)
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eig(lbnd-nbase) = eig(lbnd-nbase-1)
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END DO
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!write (6,*) ' check nactive = ', lbnd-nbase, nactive
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if (lbnd .ne. nbase+nactive ) stop ' nactive check FAILED '
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CALL divide(inter_bgrp_comm,nactive,ibnd_start,ibnd_end)
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IF ( ibnd_start > 1 ) psi2(:, nbase+1:nbase+ibnd_start-1 ) = (0.0_dp,0.0_dp)
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DO ibnd=ibnd_start,ibnd_end
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!write (*,*) ' calling pcg for ibnd = ', ibnd, eig(ibnd)
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CALL pcg_gamma(hs_1psi_ptr, g_1psi_ptr, psi2, evc, npw, npwx, nbnd, psi2(:,nbase+ibnd), ethr, iter, eig(ibnd), nhpsi)
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END DO
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IF ( ibnd_end < nactive ) psi2(:, nbase+ibnd_end+1:nbase+nactive) = (0.0_dp,0.0_dp)
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CALL mp_sum(psi2(:,nbase+1:nbase+nactive),inter_bgrp_comm)
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eig(1:nbnd) = ew(1:nbnd) ! reset first nbnd eigenvalues in their order
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#if defined(__MPI)
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IF ( nproc_ortho == 1 ) THEN
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#endif
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CALL rotate_wfc_gamma ( h_psi_ptr, s_psi_ptr, overlap, npwx, npw, ndiag, ndiag, psi2, psi2, ew )
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#if defined(__MPI)
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ELSE
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CALL protate_wfc_gamma( h_psi_ptr, s_psi_ptr, overlap, npwx, npw, ndiag, ndiag, psi2, psi2, ew )
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ENDIF
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#endif
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IF (my_bgrp_id==0) nhpsi = nhpsi + ndiag
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! only the first nbnd eigenvalues are relevant for convergence
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conv(1:nbnd) = ABS(ew(1:nbnd)-eig(1:nbnd)).LT.ethr ; nconv = COUNT(conv(:)) ; notconv = nbnd - nconv
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IF ( nconv == nbnd ) EXIT ParO_loop
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END DO ParO_loop
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evc(:,1:nbnd) = psi2(:,1:nbnd)
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eig(1:nbnd) = ew(1:nbnd)
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CALL mp_sum(nhpsi,inter_bgrp_comm)
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DEALLOCATE ( ew, conv, psi2 )
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END SUBROUTINE paro_gamma
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