--- trunk/OOPSE/libmdtools/calc_dipole_dipole.F90	2003/04/04 22:22:30	460
+++ trunk/OOPSE/libmdtools/calc_dipole_dipole.F90	2003/07/15 17:10:50	611
@@ -10,10 +10,10 @@ module dipole_dipole
 #endif
   implicit none
 
-  real(kind=dp), save :: rrf
-  real(kind=dp), save :: rt  
-  real(kind=dp), save :: rrfsq
-  real(kind=dp), save :: pre
+  real(kind=dp), save :: rrf = 0.0
+  real(kind=dp), save :: rt  = 0.0
+  real(kind=dp), save :: rrfsq = 0.0
+  real(kind=dp), save :: pre = 0.0
   logical, save :: dipole_initialized = .false.
 
 contains
@@ -39,7 +39,7 @@ contains
 
     integer atom1, atom2, me1, me2
     real(kind=dp) :: rij, mu1, mu2
-    real(kind=dp) :: dfact1, dfact2, dip2, r2, r3, r5, pre
+    real(kind=dp) :: dfact1, dfact2, dip2, r2, r3, r5
     real(kind=dp) :: dudx, dudy, dudz, dudu1x, dudu1y, dudu1z
     real(kind=dp) :: dudu2x, dudu2y, dudu2z, rdotu1, rdotu2, u1dotu2
     real(kind=dp) :: taper, dtdr, vterm
@@ -80,15 +80,7 @@ contains
     ul2(3) = u_l(3,atom2)
 #endif
 
-    if( atom1 .eq. 2 )then
-       write (*,*) 'ul =', ul1(1), ul1(2), ul1(3)
-    endif
 
-    if( atom2 .eq. 2 )then
-       write (*,*) 'ul =', ul2(1), ul2(2), ul2(3)
-    endif
-
-
     call getElementProperty(atypes, me1, "dipole_moment", mu1)
     call getElementProperty(atypes, me2, "dipole_moment", mu2)
 
@@ -101,21 +93,20 @@ contains
           taper = (rrf + 2.0d0*rij - 3.0d0*rt)*(rrf-rij)**2/ ((rrf-rt)**3)
           dtdr = 6.0d0*(rij*rij - rij*rt - rij*rrf +rrf*rt)/((rrf-rt)**3)
        endif
-       
+
        r3 = r2*rij
        r5 = r3*r2
        
        rdotu1 = d(1)*ul1(1) + d(2)*ul1(2) + d(3)*ul1(3)
        rdotu2 = d(1)*ul2(1) + d(2)*ul2(2) + d(3)*ul2(3)
        u1dotu2 = ul1(1)*ul2(1) + ul1(2)*ul2(2) + ul1(3)*ul2(3)
-       
+
        dip2 = pre * mu1 * mu2
-       
        dfact1 = 3.0d0*dip2 / r2
        dfact2 = 3.0d0*dip2 / r5
-       
+
        vterm = dip2*((u1dotu2/r3) - 3.0d0*(rdotu1*rdotu2/r5))
-       
+
        if (do_pot) then
 #ifdef IS_MPI 
           pot_row(atom1) = pot_row(atom1) + 0.5d0*vterm*taper
@@ -139,24 +130,24 @@ contains
             (5.0d0*(rdotu1*rdotu2)/r5)) -  &
             dfact2*(ul1(3)*rdotu2 + ul2(3)*rdotu1))*taper +  &
             vterm*dtdr*d(3)/rij
-       
+
        dudu1x = (dip2*((ul2(1)/r3) - (3.0d0*d(1)*rdotu2/r5)))*taper
        dudu1y = (dip2*((ul2(2)/r3) - (3.0d0*d(2)*rdotu2/r5)))*taper
        dudu1z = (dip2*((ul2(3)/r3) - (3.0d0*d(3)*rdotu2/r5)))*taper
-       
+
        dudu2x = (dip2*((ul1(1)/r3) - (3.0d0*d(1)*rdotu1/r5)))*taper
        dudu2y = (dip2*((ul1(2)/r3) - (3.0d0*d(2)*rdotu1/r5)))*taper
        dudu2z = (dip2*((ul1(3)/r3) - (3.0d0*d(3)*rdotu1/r5)))*taper
        
-       
+
 #ifdef IS_MPI
-       f_Row(1,atom1) = f_Row(1,atom1) - dudx
-       f_Row(2,atom1) = f_Row(2,atom1) - dudy
-       f_Row(3,atom1) = f_Row(3,atom1) - dudz
+       f_Row(1,atom1) = f_Row(1,atom1) + dudx
+       f_Row(2,atom1) = f_Row(2,atom1) + dudy
+       f_Row(3,atom1) = f_Row(3,atom1) + dudz
 
-       f_Col(1,atom2) = f_Col(1,atom2) + dudx
-       f_Col(2,atom2) = f_Col(2,atom2) + dudy
-       f_Col(3,atom2) = f_Col(3,atom2) + dudz
+       f_Col(1,atom2) = f_Col(1,atom2) - dudx
+       f_Col(2,atom2) = f_Col(2,atom2) - dudy
+       f_Col(3,atom2) = f_Col(3,atom2) - dudz
        
        t_Row(1,atom1) = t_Row(1,atom1) - ul1(2)*dudu1z + ul1(3)*dudu1y
        t_Row(2,atom1) = t_Row(2,atom1) - ul1(3)*dudu1x + ul1(1)*dudu1z
@@ -166,13 +157,13 @@ contains
        t_Col(2,atom2) = t_Col(2,atom2) - ul2(3)*dudu2x + ul2(1)*dudu2z
        t_Col(3,atom2) = t_Col(3,atom2) - ul2(1)*dudu2y + ul2(2)*dudu2x
 #else
-       f(1,atom1) = f(1,atom1) - dudx
-       f(2,atom1) = f(2,atom1) - dudy
-       f(3,atom1) = f(3,atom1) - dudz
+       f(1,atom1) = f(1,atom1) + dudx
+       f(2,atom1) = f(2,atom1) + dudy
+       f(3,atom1) = f(3,atom1) + dudz
        
-       f(1,atom2) = f(1,atom2) + dudx
-       f(2,atom2) = f(2,atom2) + dudy
-       f(3,atom2) = f(3,atom2) + dudz
+       f(1,atom2) = f(1,atom2) - dudx
+       f(2,atom2) = f(2,atom2) - dudy
+       f(3,atom2) = f(3,atom2) - dudz
        
        t(1,atom1) = t(1,atom1) - ul1(2)*dudu1z + ul1(3)*dudu1y
        t(2,atom1) = t(2,atom1) - ul1(3)*dudu1x + ul1(1)*dudu1z
@@ -184,16 +175,27 @@ contains
 #endif
        
        if (do_stress) then          
-          tau_Temp(1) = tau_Temp(1) + dudx * d(1)
-          tau_Temp(2) = tau_Temp(2) + dudx * d(2)
-          tau_Temp(3) = tau_Temp(3) + dudx * d(3)
-          tau_Temp(4) = tau_Temp(4) + dudy * d(1)
-          tau_Temp(5) = tau_Temp(5) + dudy * d(2)
-          tau_Temp(6) = tau_Temp(6) + dudy * d(3)
-          tau_Temp(7) = tau_Temp(7) + dudz * d(1)
-          tau_Temp(8) = tau_Temp(8) + dudz * d(2)
-          tau_Temp(9) = tau_Temp(9) + dudz * d(3)
-          virial_Temp = virial_Temp + (tau_Temp(1) + tau_Temp(5) + tau_Temp(9))
+
+          if (molMembershipList(atom1) .ne. molMembershipList(atom2)) then
+
+             ! because the d vector is the rj - ri vector, and 
+             ! because dudx, dudy, dudz are the (positive) force on
+             ! atom i (negative on atom j) we need a negative sign here:
+
+             tau_Temp(1) = tau_Temp(1) - d(1) * dudx
+             tau_Temp(2) = tau_Temp(2) - d(1) * dudy
+             tau_Temp(3) = tau_Temp(3) - d(1) * dudz
+             tau_Temp(4) = tau_Temp(4) - d(2) * dudx
+             tau_Temp(5) = tau_Temp(5) - d(2) * dudy
+             tau_Temp(6) = tau_Temp(6) - d(2) * dudz
+             tau_Temp(7) = tau_Temp(7) - d(3) * dudx
+             tau_Temp(8) = tau_Temp(8) - d(3) * dudy
+             tau_Temp(9) = tau_Temp(9) - d(3) * dudz
+
+             virial_Temp = virial_Temp + &
+                  (tau_Temp(1) + tau_Temp(5) + tau_Temp(9))
+
+          endif          
        endif
        
     endif