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Comparing trunk/OOPSE-4/src/UseTheForce/DarkSide/electrostatic.F90 (file contents):
Revision 2409 by chrisfen, Wed Nov 2 20:36:25 2005 UTC vs.
Revision 2415 by chrisfen, Thu Nov 3 23:12:27 2005 UTC

# Line 58 | Line 58 | module electrostatic_module
58   #define __FORTRAN90
59   #include "UseTheForce/DarkSide/fInteractionMap.h"
60   #include "UseTheForce/DarkSide/fElectrostaticSummationMethod.h"
61 < #include "UseTheForce/DarkSide/fScreeningMethod.h"
61 > #include "UseTheForce/DarkSide/fElectrostaticScreeningMethod.h"
62  
63  
64    !! these prefactors convert the multipole interactions into kcal / mol
# Line 75 | Line 75 | module electrostatic_module
75    !! This unit is also known affectionately as an esu centi-barn.
76    real(kind=dp), parameter :: pre14 = 69.13373_dp
77  
78 <  !! variables to handle different summation methods for long-range electrostatics:
78 >  !! variables to handle different summation methods for long-range
79 >  !! electrostatics:
80    integer, save :: summationMethod = NONE
81    integer, save :: screeningMethod = UNDAMPED
82    logical, save :: summationMethodChecked = .false.
# Line 83 | Line 84 | module electrostatic_module
84    real(kind=DP), save :: defaultCutoff2 = 0.0_DP
85    logical, save :: haveDefaultCutoff = .false.
86    real(kind=DP), save :: dampingAlpha = 0.0_DP
87 +  real(kind=DP), save :: alpha2 = 0.0_DP
88    logical, save :: haveDampingAlpha = .false.
89    real(kind=DP), save :: dielectric = 1.0_DP
90    logical, save :: haveDielectric = .false.
89 –  real(kind=DP), save :: constERFC = 0.0_DP
91    real(kind=DP), save :: constEXP = 0.0_DP
92    real(kind=dp), save :: rcuti = 0.0_DP
93    real(kind=dp), save :: rcuti2 = 0.0_DP
# Line 99 | Line 100 | module electrostatic_module
100    real(kind=dp), save :: rrfsq = 1.0_DP
101    real(kind=dp), save :: preRF = 0.0_DP
102    real(kind=dp), save :: preRF2 = 0.0_DP
103 <
103 >  real(kind=dp), save :: f0 = 1.0_DP
104 >  real(kind=dp), save :: f1 = 1.0_DP
105 >  real(kind=dp), save :: f2 = 0.0_DP
106 >  real(kind=dp), save :: f0c = 1.0_DP
107 >  real(kind=dp), save :: f1c = 1.0_DP
108 >  real(kind=dp), save :: f2c = 0.0_DP
109 >
110   #ifdef __IFC
111   ! error function for ifc version > 7.
112    double precision, external :: derfc
# Line 167 | Line 174 | contains
174    subroutine setDampingAlpha(thisAlpha)
175      real(kind=dp), intent(in) :: thisAlpha
176      dampingAlpha = thisAlpha
177 +    alpha2 = dampingAlpha*dampingAlpha
178      haveDampingAlpha = .true.
179    end subroutine setDampingAlpha
180    
# Line 406 | Line 414 | contains
414            call handleError("checkSummationMethod", "no Default Cutoff set!")
415         endif
416  
417 <       constEXP = exp(-dampingAlpha*dampingAlpha*defaultCutoff*defaultCutoff)
410 <       constERFC = derfc(dampingAlpha*defaultCutoff)
417 >       constEXP = exp(-alpha2*defaultCutoff*defaultCutoff)
418         invRootPi = 0.56418958354775628695d0
419 <       alphaPi = 2*dampingAlpha*invRootPi
420 <      
419 >       alphaPi = 2.0d0*dampingAlpha*invRootPi
420 >       f0c = derfc(dampingAlpha*defaultCutoff)
421 >       f1c = alphaPi*defaultCutoff*constEXP + f0c
422 >       f2c = alphaPi*2.0d0*alpha2*constEXP*rcuti2
423 >
424      endif
425  
426      if (summationMethod .eq. REACTION_FIELD) then
# Line 428 | Line 438 | contains
438      summationMethodChecked = .true.
439    end subroutine checkSummationMethod
440  
441 < !!$
432 < !!$  subroutine doElectrostaticPair(atom1, atom2, d, rij, r2, sw, &
433 < !!$       vpair, fpair, pot, eFrame, f, t, do_pot)
441 >
442    subroutine doElectrostaticPair(atom1, atom2, d, rij, r2, sw, &
443 <       vpair, fpair, pot, eFrame, f, t, do_pot, fstrs)
443 >       vpair, fpair, pot, eFrame, f, t, do_pot)
444  
445      logical, intent(in) :: do_pot
446  
# Line 443 | Line 451 | contains
451      real(kind=dp), intent(in), dimension(3) :: d
452      real(kind=dp), intent(inout) :: vpair
453      real(kind=dp), intent(inout), dimension(3) :: fpair    
446 –    real(kind=dp), intent(inout), dimension(3) :: fstrs
454  
455      real( kind = dp ) :: pot
456      real( kind = dp ), dimension(9,nLocal) :: eFrame
# Line 472 | Line 479 | contains
479      real (kind=dp) :: xhat, yhat, zhat
480      real (kind=dp) :: dudx, dudy, dudz
481      real (kind=dp) :: scale, sc2, bigR
482 <    real (kind=dp) :: varERFC, varEXP
482 >    real (kind=dp) :: varEXP
483      real (kind=dp) :: limScale
484      real (kind=dp) :: preVal, rfVal
485  
# Line 641 | Line 648 | contains
648         if (j_is_Charge) then
649  
650            if (summationMethod .eq. SHIFTED_POTENTIAL) then
651 +             if (screeningMethod .eq. DAMPED) then
652 +                f0 = derfc(dampingAlpha*rij)
653 +                varEXP = exp(-alpha2*rij*rij)
654 +                f1 = alphaPi*rij*varEXP + f0c
655 +             endif
656  
657 <             vterm = pre11 * q_i * q_j * (riji - rcuti)
657 >             vterm = pre11 * q_i * q_j * (riji*f0 - rcuti*f0c)
658               vpair = vpair + vterm
659               epot = epot + sw*vterm
660              
661 <             dudr  = -sw*pre11*q_i*q_j * (riji*riji)
661 >             dudr  = -sw*pre11*q_i*q_j * riji * riji * f1
662              
663               dudx = dudx + dudr * xhat
664               dudy = dudy + dudr * yhat
665               dudz = dudz + dudr * zhat
666  
655 – !!$          elseif (summationMethod .eq. DAMPED_WOLF) then
656 – !!$             varERFC = derfc(dampingAlpha*rij)
657 – !!$             varEXP = exp(-dampingAlpha*dampingAlpha*rij*rij)
658 – !!$             vterm = pre11 * q_i * q_j * (varERFC*riji - constERFC*rcuti)
659 – !!$             vpair = vpair + vterm
660 – !!$             epot = epot + sw*vterm
661 – !!$            
662 – !!$!             dudr  = -sw*pre11*q_i*q_j * (((varERFC*riji*riji &
663 – !!$!                  + alphaPi*varEXP*riji) - (constERFC*rcuti2 &
664 – !!$!                  + alphaPi*constEXP*rcuti)) )
665 – !!$             dudr  = -sw*pre11*q_i*q_j * (varERFC*riji*riji &
666 – !!$                  + alphaPi*varEXP*riji)
667 – !!$            
668 – !!$             dudx = dudx + dudr * xhat
669 – !!$             dudy = dudy + dudr * yhat
670 – !!$             dudz = dudz + dudr * zhat
671 –
667            elseif (summationMethod .eq. SHIFTED_FORCE) then
668 <             vterm = pre11 * q_i * q_j * (riji + rij*rcuti2 - 2.0d0*rcuti)
668 >             if (screeningMethod .eq. DAMPED) then
669 >                f0 = derfc(dampingAlpha*rij)
670 >                varEXP = exp(-alpha2*rij*rij)
671 >                f1 = alphaPi*rij*varEXP + f0
672 >             endif
673 >            
674 >             vterm = pre11 * q_i * q_j * ( riji*f0 - rcuti*f0c + &
675 >                  f1c*rcuti2*(rij-defaultCutoff) )
676 >            
677               vpair = vpair + vterm
678               epot = epot + sw*vterm
679              
680 <             dudr  = -sw*pre11*q_i*q_j * (riji*riji-rcuti2)
680 >             dudr  = -sw*pre11*q_i*q_j * (riji*riji*f1 - rcuti2*f1c)
681                            
682               dudx = dudx + dudr * xhat
683               dudy = dudy + dudr * yhat
684               dudz = dudz + dudr * zhat
682 –
683 – !!$          elseif (summationMethod .eq. DAMPED_SHIFTED_FORCE) then
684 – !!$             varERFC = derfc(dampingAlpha*rij)
685 – !!$             varEXP = exp(-dampingAlpha*dampingAlpha*rij*rij)
686 – !!$             vterm = pre11 * q_i * q_j * (varERFC*riji - constERFC*rcuti)
687 – !!$             vpair = vpair + vterm
688 – !!$             epot = epot + sw*vterm
689 – !!$            
690 – !!$!             dudr  = -sw*pre11*q_i*q_j * (((varERFC*riji*riji &
691 – !!$!                  + alphaPi*varEXP*riji) - (constERFC*rcuti2 &
692 – !!$!                  + alphaPi*constEXP*rcuti)) )
693 – !!$             dudr  = -sw*pre11*q_i*q_j * (varERFC*riji*riji &
694 – !!$                  + alphaPi*varEXP*riji)
695 – !!$            
696 – !!$             dudx = dudx + dudr * xhat
697 – !!$             dudy = dudy + dudr * yhat
698 – !!$             dudz = dudz + dudr * zhat
685  
686            elseif (summationMethod .eq. REACTION_FIELD) then
687               preVal = pre11 * q_i * q_j
# Line 1030 | Line 1016 | contains
1016   !!$             duduz_j(3) = duduz_j(3) + sw*pref*(ri3*(uz_i(3)-3.0d0*ct_i*zhat) &
1017   !!$                  - rcuti3*(uz_i(3) - 3.0d0*ct_i*zhat))
1018   !!$          
1033 – !!$          elseif (summationMethod .eq. DAMPED_WOLF) then
1034 – !!$             ct_ij = uz_i(1)*uz_j(1) + uz_i(2)*uz_j(2) + uz_i(3)*uz_j(3)
1035 – !!$            
1036 – !!$             ri2 = riji * riji
1037 – !!$             ri3 = ri2 * riji
1038 – !!$             ri4 = ri2 * ri2
1039 – !!$             sc2 = scale * scale
1040 – !!$            
1041 – !!$             pref = pre22 * mu_i * mu_j
1042 – !!$             vterm = pref * ri3 * (ct_ij - 3.0d0 * ct_i * ct_j)
1043 – !!$             vpair = vpair + vterm
1044 – !!$             epot = epot + sw*vterm
1045 – !!$            
1046 – !!$             a1 = 5.0d0 * ct_i * ct_j * sc2 - ct_ij
1047 – !!$            
1048 – !!$             dudx = dudx + sw*pref*3.0d0*ri4*(a1*xhat-ct_i*uz_j(1)-ct_j*uz_i(1))
1049 – !!$             dudy = dudy + sw*pref*3.0d0*ri4*(a1*yhat-ct_i*uz_j(2)-ct_j*uz_i(2))
1050 – !!$             dudz = dudz + sw*pref*3.0d0*ri4*(a1*zhat-ct_i*uz_j(3)-ct_j*uz_i(3))
1051 – !!$            
1052 – !!$             duduz_i(1) = duduz_i(1) + sw*pref*ri3 *(uz_j(1) - 3.0d0*ct_j*xhat)
1053 – !!$             duduz_i(2) = duduz_i(2) + sw*pref*ri3 *(uz_j(2) - 3.0d0*ct_j*yhat)
1054 – !!$             duduz_i(3) = duduz_i(3) + sw*pref*ri3 *(uz_j(3) - 3.0d0*ct_j*zhat)
1055 – !!$            
1056 – !!$             duduz_j(1) = duduz_j(1) + sw*pref*ri3 *(uz_i(1) - 3.0d0*ct_i*xhat)
1057 – !!$             duduz_j(2) = duduz_j(2) + sw*pref*ri3 *(uz_i(2) - 3.0d0*ct_i*yhat)
1058 – !!$             duduz_j(3) = duduz_j(3) + sw*pref*ri3 *(uz_i(3) - 3.0d0*ct_i*zhat)
1059 – !!$            
1019   !!$          elseif (summationMethod .eq. REACTION_FIELD) then
1020            if (summationMethod .eq. REACTION_FIELD) then
1021               ct_ij = uz_i(1)*uz_j(1) + uz_i(2)*uz_j(2) + uz_i(3)*uz_j(3)
# Line 1409 | Line 1368 | contains
1368            
1369         endif
1370  
1371 < !!$    elseif (summationMethod .eq. UNDAMPED_WOLF) then
1371 > !!$    elseif (summationMethod .eq. SHIFTED_FORCE) then
1372   !!$       if (ElectrostaticMap(atid1)%is_Charge) then
1373   !!$          c1 = getCharge(atid1)
1374   !!$          
1375 < !!$          mypot = mypot - (rcuti * 0.5_dp * c1 * c1)
1375 > !!$          if (screeningMethod .eq. DAMPED) then
1376 > !!$             mypot = mypot - (f0c * rcuti * 0.5_dp + &
1377 > !!$                  dampingAlpha*invRootPi) * c1 * c1    
1378 > !!$            
1379 > !!$          else            
1380 > !!$             mypot = mypot - (rcuti * 0.5_dp * c1 * c1)
1381 > !!$            
1382 > !!$          endif
1383   !!$       endif
1384 < !!$      
1419 < !!$    elseif (summationMethod .eq. DAMPED_WOLF) then
1420 < !!$       if (ElectrostaticMap(atid1)%is_Charge) then
1421 < !!$          c1 = getCharge(atid1)
1422 < !!$          
1423 < !!$          mypot = mypot - (constERFC * rcuti * 0.5_dp + &
1424 < !!$               dampingAlpha*invRootPi) * c1 * c1      
1425 < !!$       endif
1426 <    endif
1384 > !!$    endif
1385      
1386      return
1387    end subroutine self_self

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