1! 2! Copyright (C) 2003 PWSCF group 3! This file is distributed under the terms of the 4! GNU General Public License. See the file `License' 5! in the root directory of the present distribution, 6! or http://www.gnu.org/copyleft/gpl.txt . 7! 8! 9!----------------------------------------------------------------------- 10SUBROUTINE A_h(npw,e,h,ah) 11 !----------------------------------------------------------------------- 12 USE kinds, ONLY: DP 13 USE cell_base,ONLY : alat, omega, tpiba2 14 USE uspp, ONLY : vkb, nkb 15 USE lsda_mod, ONLY : current_spin, nspin 16 USE wvfct, ONLY: nbnd, npwx, g2kin 17 USE wavefunctions, ONLY: evc, psic 18 USE scf, ONLY : vrs, rho 19 USE fft_base, ONLY : dffts, dfftp 20 USE fft_interfaces, ONLY : fwfft, invfft 21 USE gvect, ONLY : gstart, g, gg 22 USE constants, ONLY: degspin, e2, fpi 23 USE becmod, ONLY: bec_type, becp, calbec 24 USE gc_lr, ONLY: grho, dvxc_rr, dvxc_sr, dvxc_ss, dvxc_s 25 USE cgcom, ONLY: auxr, aux2, aux3, dmuxc 26 USE funct, ONLY: dft_is_gradient 27 ! 28 IMPLICIT NONE 29 INTEGER :: npw, j, jkb, ibnd, na,nt,ih 30 real(DP) :: e(nbnd) 31 COMPLEX(DP) :: h(npwx,nbnd), ah(npwx,nbnd) 32 ! 33 COMPLEX(DP) :: fp, fm 34 COMPLEX(DP), POINTER :: dpsic(:), drhoc(:) 35 REAL(dp), allocatable :: dv(:) 36 real(DP), POINTER :: drho(:) 37 ! 38 CALL start_clock('a_h') 39 ! 40 drho => auxr 41 dpsic => aux2 42 drhoc => aux3 43 ! 44 drho(:) = 0.d0 45 ! 46 ! [(k+G)^2 - e ]psi 47 DO ibnd = 1,nbnd 48 ! set to zero the imaginary part of h at G=0 49 ! needed for numerical stability 50 IF (gstart==2) h(1,ibnd) = cmplx( dble(h(1,ibnd)),0.d0,kind=DP) 51 DO j = 1,npw 52 ah(j,ibnd) = (g2kin(j)-e(ibnd)) * h(j,ibnd) 53 ENDDO 54 ENDDO 55 ! V_Loc psi 56 DO ibnd = 1,nbnd, 2 57 dpsic(:)= (0.d0, 0.d0) 58 psic(:) = (0.d0, 0.d0) 59 IF (ibnd<nbnd) THEN 60 ! two ffts at the same time 61 DO j = 1,npw 62 psic (dfftp%nl (j)) = evc(j,ibnd) + (0.0d0,1.d0)* evc(j,ibnd+1) 63 dpsic(dfftp%nl (j)) = h(j,ibnd) + (0.0d0,1.d0)* h(j,ibnd+1) 64 psic (dfftp%nlm(j))= conjg(evc(j,ibnd)-(0.0d0,1.d0)* evc(j,ibnd+1)) 65 dpsic(dfftp%nlm(j))= conjg( h(j,ibnd)-(0.0d0,1.d0)* h(j,ibnd+1)) 66 ENDDO 67 ELSE 68 DO j = 1,npw 69 psic (dfftp%nl (j)) = evc(j,ibnd) 70 dpsic(dfftp%nl (j)) = h(j,ibnd) 71 psic (dfftp%nlm(j)) = conjg( evc(j,ibnd)) 72 dpsic(dfftp%nlm(j)) = conjg( h(j,ibnd)) 73 ENDDO 74 ENDIF 75 CALL invfft ('Wave', psic, dffts) 76 CALL invfft ('Wave',dpsic, dffts) 77 DO j = 1,dfftp%nnr 78 drho(j) = drho(j) - 2.0d0*degspin/omega * & 79 dble(psic(j)*conjg(dpsic(j))) 80 dpsic(j) = dpsic(j) * vrs(j,current_spin) 81 ENDDO 82 CALL fwfft ('Wave',dpsic, dffts) 83 IF (ibnd<nbnd) THEN 84 ! two ffts at the same time 85 DO j = 1,npw 86 fp = (dpsic (dfftp%nl(j)) + dpsic (dfftp%nlm(j)))*0.5d0 87 fm = (dpsic (dfftp%nl(j)) - dpsic (dfftp%nlm(j)))*0.5d0 88 ah(j,ibnd ) = ah(j,ibnd) +cmplx( dble(fp), aimag(fm),kind=DP) 89 ah(j,ibnd+1) = ah(j,ibnd+1)+cmplx(aimag(fp),- dble(fm),kind=DP) 90 ENDDO 91 ELSE 92 DO j = 1,npw 93 ah(j,ibnd) = ah(j,ibnd) + dpsic (dfftp%nl(j)) 94 ENDDO 95 ENDIF 96 ENDDO 97 ! 98 ! V_NL psi 99 CALL calbec ( npw, vkb, h, becp) 100 IF (nkb > 0) CALL add_vuspsi (npwx, npw, nbnd, ah) 101 ! 102 DO j = 1,dfftp%nnr 103 drhoc(j) = cmplx(drho(j),0.d0,kind=DP) 104 ENDDO 105 CALL fwfft ('Rho', drhoc, dfftp) 106 DO j = 1,dfftp%ngm 107 dpsic(j) = drhoc(dfftp%nl(j)) 108 ENDDO 109 ! 110 ! drho is deltarho(r) 111 ! drhoc is deltarho(g) on the FFT grid 112 ! dpsic is deltarho(g) on the G-vector grid 113 ! 114 ! mu'(n(r)) psi(r) delta psi(r) 115 ! 116 ALLOCATE (dv(dfftp%nnr)) 117 DO j = 1,dfftp%nnr 118 dv(j) = drho(j)*dmuxc(j) 119 ENDDO 120 ! 121 ! add gradient correction contribution (if any) 122 ! 123 CALL start_clock('dgradcorr') 124 IF (dft_is_gradient() ) THEN 125 ! 126 CALL dgradcor1 & 127 (dfftp, rho%of_r, grho, dvxc_rr, dvxc_sr, dvxc_ss, dvxc_s, & 128 drho, dpsic, nspin, g, dv) 129 ! 130 ENDIF 131 CALL stop_clock('dgradcorr') 132 NULLIFY(dpsic) 133 NULLIFY (drho) 134 ! 135 ! 1/|r-r'| * psi(r') delta psi(r') 136 ! 137 ! gstart is the first nonzero G vector (needed for parallel execution) 138 ! 139 IF (gstart==2) drhoc(dfftp%nl(1)) = 0.d0 140 ! 141 DO j = gstart,dfftp%ngm 142 drhoc(dfftp%nl (j)) = e2*fpi*drhoc(dfftp%nl(j))/ (tpiba2*gg(j)) 143 drhoc(dfftp%nlm(j)) = conjg(drhoc(dfftp%nl (j))) 144 ENDDO 145 CALL invfft ('Rho', drhoc, dfftp) 146 ! 147 ! drhoc now contains deltaV_hartree 148 ! 149 DO j = 1,dfftp%nnr 150 dv(j) = - dv(j) - dble(drhoc(j)) 151 ENDDO 152 ! 153 CALL vloc_psi_gamma(npwx, npw, nbnd, evc, dv, ah) 154 ! 155 NULLIFY(drhoc) 156 DEALLOCATE (dv) 157 ! 158 ! set to zero the imaginary part of ah at G=0 159 ! needed for numerical stability 160 IF (gstart==2) THEN 161 DO ibnd = 1, nbnd 162 ah(1,ibnd) = cmplx( dble(ah(1,ibnd)),0.d0,kind=DP) 163 ENDDO 164 ENDIF 165 ! 166 CALL stop_clock('a_h') 167 ! 168 RETURN 169END SUBROUTINE A_h 170