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root/OpenMD/trunk/src/UseTheForce/DarkSide/suttonchen.F90
Revision: 835
Committed: Sat Dec 31 22:42:01 2005 UTC (19 years, 4 months ago) by chuckv
File size: 19312 byte(s)
Log Message:
Sutton-Chen no longer segfaults or produces 0 potential, but rather
produces Inf for the potential. Progress....

File Contents

# User Rev Content
1 chuckv 702 !!
2     !! Copyright (c) 2005 The University of Notre Dame. All Rights Reserved.
3     !!
4     !! The University of Notre Dame grants you ("Licensee") a
5     !! non-exclusive, royalty free, license to use, modify and
6     !! redistribute this software in source and binary code form, provided
7     !! that the following conditions are met:
8     !!
9     !! 1. Acknowledgement of the program authors must be made in any
10     !! publication of scientific results based in part on use of the
11     !! program. An acceptable form of acknowledgement is citation of
12     !! the article in which the program was described (Matthew
13     !! A. Meineke, Charles F. Vardeman II, Teng Lin, Christopher
14     !! J. Fennell and J. Daniel Gezelter, "OOPSE: An Object-Oriented
15     !! Parallel Simulation Engine for Molecular Dynamics,"
16     !! J. Comput. Chem. 26, pp. 252-271 (2005))
17     !!
18     !! 2. Redistributions of source code must retain the above copyright
19     !! notice, this list of conditions and the following disclaimer.
20     !!
21     !! 3. Redistributions in binary form must reproduce the above copyright
22     !! notice, this list of conditions and the following disclaimer in the
23     !! documentation and/or other materials provided with the
24     !! distribution.
25     !!
26     !! This software is provided "AS IS," without a warranty of any
27     !! kind. All express or implied conditions, representations and
28     !! warranties, including any implied warranty of merchantability,
29     !! fitness for a particular purpose or non-infringement, are hereby
30     !! excluded. The University of Notre Dame and its licensors shall not
31     !! be liable for any damages suffered by licensee as a result of
32     !! using, modifying or distributing the software or its
33     !! derivatives. In no event will the University of Notre Dame or its
34     !! licensors be liable for any lost revenue, profit or data, or for
35     !! direct, indirect, special, consequential, incidental or punitive
36     !! damages, however caused and regardless of the theory of liability,
37     !! arising out of the use of or inability to use software, even if the
38     !! University of Notre Dame has been advised of the possibility of
39     !! such damages.
40     !!
41    
42     !! Impliments Sutton-Chen Metallic Potential
43     !! See A.P.SUTTON and J.CHEN,PHIL MAG LETT 61,139-146,1990
44    
45    
46     module suttonchen
47     use simulation
48     use force_globals
49     use status
50     use atype_module
51     use vector_class
52 chuckv 798 use fForceOptions
53 chuckv 702 #ifdef IS_MPI
54     use mpiSimulation
55     #endif
56     implicit none
57     PRIVATE
58     #define __FORTRAN90
59     #include "UseTheForce/DarkSide/fInteractionMap.h"
60    
61     INTEGER, PARAMETER :: DP = selected_real_kind(15)
62    
63     logical, save :: SC_FF_initialized = .false.
64     integer, save :: SC_Mixing_Policy
65     real(kind = dp), save :: SC_rcut
66     logical, save :: haveRcut = .false.
67 chuckv 728 logical, save :: haveMixingMap = .false.
68     logical, save :: useGeometricDistanceMixing = .false.
69 chuckv 835 logical, save :: cleanArrays = .true.
70     logical, save :: arraysAllocated = .false.
71 chuckv 702
72 chuckv 728
73 chuckv 702 character(len = statusMsgSize) :: errMesg
74 chuckv 714 integer :: sc_err
75 chuckv 702
76     character(len = 200) :: errMsg
77     character(len=*), parameter :: RoutineName = "Sutton-Chen MODULE"
78     !! Logical that determines if eam arrays should be zeroed
79     logical :: nmflag = .false.
80    
81    
82     type, private :: SCtype
83     integer :: atid
84 chuckv 707 real(kind=dp) :: c
85 chuckv 702 real(kind=dp) :: m
86     real(kind=dp) :: n
87     real(kind=dp) :: alpha
88     real(kind=dp) :: epsilon
89 chuckv 728 real(kind=dp) :: sc_rcut
90 chuckv 702 end type SCtype
91    
92    
93     !! Arrays for derivatives used in force calculation
94 chuckv 713 real( kind = dp), dimension(:), allocatable :: rho
95 chuckv 702 real( kind = dp), dimension(:), allocatable :: frho
96     real( kind = dp), dimension(:), allocatable :: dfrhodrho
97    
98    
99 chuckv 728
100 chuckv 702 !! Arrays for MPI storage
101     #ifdef IS_MPI
102     real( kind = dp),save, dimension(:), allocatable :: dfrhodrho_col
103     real( kind = dp),save, dimension(:), allocatable :: dfrhodrho_row
104     real( kind = dp),save, dimension(:), allocatable :: frho_row
105     real( kind = dp),save, dimension(:), allocatable :: frho_col
106     real( kind = dp),save, dimension(:), allocatable :: rho_row
107     real( kind = dp),save, dimension(:), allocatable :: rho_col
108     real( kind = dp),save, dimension(:), allocatable :: rho_tmp
109     #endif
110    
111     type, private :: SCTypeList
112     integer :: nSCTypes = 0
113     integer :: currentSCtype = 0
114    
115     type (SCtype), pointer :: SCtypes(:) => null()
116     integer, pointer :: atidToSCtype(:) => null()
117     end type SCTypeList
118    
119     type (SCTypeList), save :: SCList
120    
121    
122    
123 chuckv 707
124     type :: MixParameters
125     real(kind=DP) :: alpha
126     real(kind=DP) :: epsilon
127 chuckv 728 real(kind=DP) :: m
128     real(Kind=DP) :: n
129     real(kind=DP) :: vpair_pot
130 chuckv 707 real(kind=dp) :: rCut
131     logical :: rCutWasSet = .false.
132 chuckv 728
133 chuckv 707 end type MixParameters
134    
135     type(MixParameters), dimension(:,:), allocatable :: MixingMap
136    
137    
138    
139 chuckv 702 public :: setCutoffSC
140     public :: do_SC_pair
141     public :: newSCtype
142     public :: calc_SC_prepair_rho
143 chuckv 735 public :: calc_SC_preforce_Frho
144 chuckv 702 public :: clean_SC
145     public :: destroySCtypes
146     public :: getSCCut
147 chuckv 728 ! public :: setSCDefaultCutoff
148     ! public :: setSCUniformCutoff
149 chuckv 798
150 chuckv 702
151     contains
152    
153    
154 chuckv 728 subroutine newSCtype(c_ident,c,m,n,alpha,epsilon,status)
155     real (kind = dp ) :: c ! Density Scaling
156     real (kind = dp ) :: m ! Density Exponent
157     real (kind = dp ) :: n ! Pair Potential Exponent
158     real (kind = dp ) :: alpha ! Length Scaling
159     real (kind = dp ) :: epsilon ! Energy Scaling
160    
161    
162 chuckv 702 integer :: c_ident
163     integer :: status
164    
165 chuckv 713 integer :: nAtypes,nSCTypes,myATID
166 chuckv 702 integer :: maxVals
167     integer :: alloc_stat
168     integer :: current
169     integer,pointer :: Matchlist(:) => null()
170    
171     status = 0
172    
173    
174     !! Assume that atypes has already been set and get the total number of types in atypes
175    
176    
177     ! check to see if this is the first time into
178 chuckv 728 if (.not.associated(SCList%SCTypes)) then
179 chuckv 831 call getMatchingElementList(atypes, "is_SC", .true., nSCtypes, MatchList)
180 chuckv 728 SCList%nSCtypes = nSCtypes
181     allocate(SCList%SCTypes(nSCTypes))
182 chuckv 702 nAtypes = getSize(atypes)
183 chuckv 728 allocate(SCList%atidToSCType(nAtypes))
184 chuckv 702 end if
185    
186 chuckv 728 SCList%currentSCType = SCList%currentSCType + 1
187     current = SCList%currentSCType
188 chuckv 702
189     myATID = getFirstMatchingElement(atypes, "c_ident", c_ident)
190 chuckv 728 SCList%atidToSCType(myATID) = current
191 chuckv 702
192    
193    
194 chuckv 728 SCList%SCTypes(current)%atid = c_ident
195     SCList%SCTypes(current)%alpha = alpha
196     SCList%SCTypes(current)%c = c
197     SCList%SCTypes(current)%m = m
198     SCList%SCTypes(current)%n = n
199     SCList%SCTypes(current)%epsilon = epsilon
200 chuckv 713 end subroutine newSCtype
201 chuckv 702
202 chuckv 713
203     subroutine destroySCTypes()
204 chuckv 728 if (associated(SCList%SCtypes)) then
205     deallocate(SCList%SCTypes)
206     SCList%SCTypes=>null()
207     end if
208     if (associated(SCList%atidToSCtype)) then
209     deallocate(SCList%atidToSCtype)
210     SCList%atidToSCtype=>null()
211     end if
212 chuckv 702
213    
214 chuckv 713 end subroutine destroySCTypes
215 chuckv 702
216    
217 chuckv 713
218     function getSCCut(atomID) result(cutValue)
219 chuckv 702 integer, intent(in) :: atomID
220 chuckv 728 integer :: scID
221 chuckv 702 real(kind=dp) :: cutValue
222    
223 chuckv 728 scID = SCList%atidToSCType(atomID)
224 chuckv 831 cutValue = 2.0_dp * SCList%SCTypes(scID)%alpha
225 chuckv 713 end function getSCCut
226 chuckv 702
227    
228    
229 chuckv 713
230     subroutine createMixingMap()
231     integer :: nSCtypes, i, j
232     real ( kind = dp ) :: e1, e2,m1,m2,alpha1,alpha2,n1,n2
233     real ( kind = dp ) :: rcut6, tp6, tp12
234     logical :: isSoftCore1, isSoftCore2, doShift
235    
236     if (SCList%currentSCtype == 0) then
237     call handleError("SuttonChen", "No members in SCMap")
238 chuckv 702 return
239     end if
240    
241 chuckv 713 nSCtypes = SCList%nSCtypes
242 chuckv 702
243 chuckv 713 if (.not. allocated(MixingMap)) then
244     allocate(MixingMap(nSCtypes, nSCtypes))
245     endif
246 chuckv 798 useGeometricDistanceMixing = usesGeometricDistanceMixing()
247 chuckv 713 do i = 1, nSCtypes
248 chuckv 702
249 chuckv 713 e1 = SCList%SCtypes(i)%epsilon
250     m1 = SCList%SCtypes(i)%m
251     n1 = SCList%SCtypes(i)%n
252     alpha1 = SCList%SCtypes(i)%alpha
253 chuckv 702
254 chuckv 713 do j = i, nSCtypes
255    
256 chuckv 702
257 chuckv 713 e2 = SCList%SCtypes(j)%epsilon
258     m2 = SCList%SCtypes(j)%m
259     n2 = SCList%SCtypes(j)%n
260     alpha2 = SCList%SCtypes(j)%alpha
261 chuckv 702
262 chuckv 728 if (useGeometricDistanceMixing) then
263     MixingMap(i,j)%alpha = sqrt(alpha1 * alpha2) !SC formulation
264     else
265     MixingMap(i,j)%alpha = 0.5_dp * (alpha1 + alpha2) ! Goddard formulation
266     endif
267    
268     MixingMap(i,j)%epsilon = sqrt(e1 * e2)
269 chuckv 713 MixingMap(i,j)%m = 0.5_dp*(m1+m2)
270     MixingMap(i,j)%n = 0.5_dp*(n1+n2)
271     MixingMap(i,j)%alpha = 0.5_dp*(alpha1+alpha2)
272     MixingMap(i,j)%rcut = 2.0_dp *MixingMap(i,j)%alpha
273 chuckv 728 MixingMap(i,j)%vpair_pot = MixingMap(i,j)%epsilon* &
274     (MixingMap(i,j)%alpha/MixingMap(i,j)%rcut)**MixingMap(i,j)%n
275     if (i.ne.j) then
276     MixingMap(j,i)%epsilon = MixingMap(i,j)%epsilon
277     MixingMap(j,i)%m = MixingMap(i,j)%m
278     MixingMap(j,i)%n = MixingMap(i,j)%n
279     MixingMap(j,i)%alpha = MixingMap(i,j)%alpha
280     MixingMap(j,i)%rcut = MixingMap(i,j)%rcut
281     MixingMap(j,i)%vpair_pot = MixingMap(i,j)%vpair_pot
282     endif
283 chuckv 713 enddo
284 chuckv 702 enddo
285 chuckv 713
286     haveMixingMap = .true.
287    
288     end subroutine createMixingMap
289    
290 chuckv 702
291     !! routine checks to see if array is allocated, deallocates array if allocated
292     !! and then creates the array to the required size
293 chuckv 835 subroutine allocateSC()
294     integer :: status
295 chuckv 702
296     #ifdef IS_MPI
297     integer :: nAtomsInRow
298     integer :: nAtomsInCol
299     #endif
300     integer :: alloc_stat
301    
302 chuckv 835
303 chuckv 702 status = 0
304     #ifdef IS_MPI
305     nAtomsInRow = getNatomsInRow(plan_atom_row)
306     nAtomsInCol = getNatomsInCol(plan_atom_col)
307     #endif
308    
309 chuckv 713
310    
311 chuckv 702 if (allocated(frho)) deallocate(frho)
312     allocate(frho(nlocal),stat=alloc_stat)
313 chuckv 713 if (alloc_stat /= 0) then
314 chuckv 702 status = -1
315     end if
316 chuckv 713
317 chuckv 702 if (allocated(rho)) deallocate(rho)
318     allocate(rho(nlocal),stat=alloc_stat)
319     if (alloc_stat /= 0) then
320     status = -1
321     end if
322    
323     if (allocated(dfrhodrho)) deallocate(dfrhodrho)
324     allocate(dfrhodrho(nlocal),stat=alloc_stat)
325     if (alloc_stat /= 0) then
326     status = -1
327     end if
328    
329     #ifdef IS_MPI
330    
331     if (allocated(rho_tmp)) deallocate(rho_tmp)
332     allocate(rho_tmp(nlocal),stat=alloc_stat)
333     if (alloc_stat /= 0) then
334     status = -1
335     end if
336    
337    
338     if (allocated(frho_row)) deallocate(frho_row)
339     allocate(frho_row(nAtomsInRow),stat=alloc_stat)
340     if (alloc_stat /= 0) then
341     status = -1
342     end if
343     if (allocated(rho_row)) deallocate(rho_row)
344     allocate(rho_row(nAtomsInRow),stat=alloc_stat)
345     if (alloc_stat /= 0) then
346     status = -1
347     end if
348     if (allocated(dfrhodrho_row)) deallocate(dfrhodrho_row)
349     allocate(dfrhodrho_row(nAtomsInRow),stat=alloc_stat)
350     if (alloc_stat /= 0) then
351     status = -1
352     end if
353    
354    
355     ! Now do column arrays
356    
357     if (allocated(frho_col)) deallocate(frho_col)
358     allocate(frho_col(nAtomsInCol),stat=alloc_stat)
359     if (alloc_stat /= 0) then
360     status = -1
361     end if
362     if (allocated(rho_col)) deallocate(rho_col)
363     allocate(rho_col(nAtomsInCol),stat=alloc_stat)
364     if (alloc_stat /= 0) then
365     status = -1
366     end if
367     if (allocated(dfrhodrho_col)) deallocate(dfrhodrho_col)
368     allocate(dfrhodrho_col(nAtomsInCol),stat=alloc_stat)
369     if (alloc_stat /= 0) then
370     status = -1
371     end if
372    
373     #endif
374 chuckv 835 if (status == -1) then
375     call handleError("SuttonChen:allocateSC","Error in allocating SC arrays")
376     end if
377     arraysAllocated = .true.
378 chuckv 713 end subroutine allocateSC
379 chuckv 702
380     !! C sets rcut to be the largest cutoff of any atype
381     !! present in this simulation. Doesn't include all atypes
382     !! sim knows about, just those in the simulation.
383 chuckv 713 subroutine setCutoffSC(rcut, status)
384 chuckv 702 real(kind=dp) :: rcut
385     integer :: status
386     status = 0
387    
388 chuckv 713 SC_rcut = rcut
389 chuckv 702
390 chuckv 713 end subroutine setCutoffSC
391 chuckv 702
392 chuckv 835 !! This array allocates module arrays if needed and builds mixing map.
393 chuckv 728 subroutine clean_SC()
394 chuckv 835 if (.not.arraysAllocated) call allocateSC()
395     if (.not.haveMixingMap) call createMixingMap()
396 chuckv 702 ! clean non-IS_MPI first
397     frho = 0.0_dp
398     rho = 0.0_dp
399     dfrhodrho = 0.0_dp
400     ! clean MPI if needed
401     #ifdef IS_MPI
402     frho_row = 0.0_dp
403     frho_col = 0.0_dp
404     rho_row = 0.0_dp
405     rho_col = 0.0_dp
406     rho_tmp = 0.0_dp
407     dfrhodrho_row = 0.0_dp
408     dfrhodrho_col = 0.0_dp
409     #endif
410 chuckv 728 end subroutine clean_SC
411 chuckv 702
412    
413    
414     !! Calculates rho_r
415 gezelter 762 subroutine calc_sc_prepair_rho(atom1,atom2,d,r,rijsq, rcut)
416 chuckv 702 integer :: atom1,atom2
417     real(kind = dp), dimension(3) :: d
418     real(kind = dp), intent(inout) :: r
419 gezelter 762 real(kind = dp), intent(inout) :: rijsq, rcut
420 chuckv 702 ! value of electron density rho do to atom i at atom j
421     real(kind = dp) :: rho_i_at_j
422     ! value of electron density rho do to atom j at atom i
423     real(kind = dp) :: rho_j_at_i
424    
425     ! we don't use the derivatives, dummy variables
426 chuckv 728 real( kind = dp) :: drho
427 chuckv 714 integer :: sc_err
428 chuckv 702
429     integer :: atid1,atid2 ! Global atid
430     integer :: myid_atom1 ! EAM atid
431     integer :: myid_atom2
432    
433    
434     ! check to see if we need to be cleaned at the start of a force loop
435    
436 chuckv 835 if (cleanArrays) call clean_SC()
437     cleanArrays = .false.
438 chuckv 702
439     #ifdef IS_MPI
440     Atid1 = Atid_row(Atom1)
441     Atid2 = Atid_col(Atom2)
442     #else
443     Atid1 = Atid(Atom1)
444     Atid2 = Atid(Atom2)
445     #endif
446    
447 chuckv 728 Myid_atom1 = SCList%atidtoSCtype(Atid1)
448     Myid_atom2 = SCList%atidtoSCtype(Atid2)
449 chuckv 702
450    
451    
452 chuckv 713 rho_i_at_j = (MixingMap(Myid_atom1,Myid_atom2)%alpha/r)&
453     **MixingMap(Myid_atom1,Myid_atom2)%m
454     rho_j_at_i = rho_i_at_j
455 chuckv 702
456     #ifdef IS_MPI
457     rho_col(atom2) = rho_col(atom2) + rho_i_at_j
458 chuckv 713 rho_row(atom1) = rho_row(atom1) + rho_j_at_i
459 chuckv 702 #else
460     rho(atom2) = rho(atom2) + rho_i_at_j
461     rho(atom1) = rho(atom1) + rho_j_at_i
462     #endif
463    
464 chuckv 713 end subroutine calc_sc_prepair_rho
465 chuckv 702
466    
467 chuckv 714 !! Calculate the rho_a for all local atoms
468 chuckv 728 subroutine calc_sc_preforce_Frho(nlocal,pot)
469 chuckv 702 integer :: nlocal
470     real(kind=dp) :: pot
471     integer :: i,j
472     integer :: atom
473     real(kind=dp) :: U,U1,U2
474     integer :: atype1
475 chuckv 728 integer :: atid1
476     integer :: myid
477 chuckv 702
478    
479     !! Scatter the electron density from pre-pair calculation back to local atoms
480     #ifdef IS_MPI
481 chuckv 714 call scatter(rho_row,rho,plan_atom_row,sc_err)
482     if (sc_err /= 0 ) then
483 chuckv 702 write(errMsg,*) " Error scattering rho_row into rho"
484     call handleError(RoutineName,errMesg)
485     endif
486 chuckv 714 call scatter(rho_col,rho_tmp,plan_atom_col,sc_err)
487     if (sc_err /= 0 ) then
488 chuckv 702 write(errMsg,*) " Error scattering rho_col into rho"
489     call handleError(RoutineName,errMesg)
490 chuckv 713
491 chuckv 702 endif
492    
493     rho(1:nlocal) = rho(1:nlocal) + rho_tmp(1:nlocal)
494     #endif
495    
496    
497    
498 chuckv 713 !! Calculate F(rho) and derivative
499 chuckv 702 do atom = 1, nlocal
500 chuckv 728 Myid = SCList%atidtoSctype(Atid(atom))
501     frho(atom) = -SCList%SCTypes(Myid)%c * &
502     SCList%SCTypes(Myid)%epsilon * sqrt(rho(i))
503    
504 chuckv 713 dfrhodrho(atom) = 0.5_dp*frho(atom)/rho(atom)
505 chuckv 702 pot = pot + u
506     enddo
507    
508 chuckv 731 #ifdef IS_MPI
509 chuckv 702 !! communicate f(rho) and derivatives back into row and column arrays
510 chuckv 714 call gather(frho,frho_row,plan_atom_row, sc_err)
511     if (sc_err /= 0) then
512 chuckv 702 call handleError("cal_eam_forces()","MPI gather frho_row failure")
513     endif
514 chuckv 714 call gather(dfrhodrho,dfrhodrho_row,plan_atom_row, sc_err)
515     if (sc_err /= 0) then
516 chuckv 702 call handleError("cal_eam_forces()","MPI gather dfrhodrho_row failure")
517     endif
518 chuckv 714 call gather(frho,frho_col,plan_atom_col, sc_err)
519     if (sc_err /= 0) then
520 chuckv 702 call handleError("cal_eam_forces()","MPI gather frho_col failure")
521     endif
522 chuckv 714 call gather(dfrhodrho,dfrhodrho_col,plan_atom_col, sc_err)
523     if (sc_err /= 0) then
524 chuckv 702 call handleError("cal_eam_forces()","MPI gather dfrhodrho_col failure")
525     endif
526     #endif
527 chuckv 713
528    
529 chuckv 728 end subroutine calc_sc_preforce_Frho
530 chuckv 702
531    
532 chuckv 713 !! Does Sutton-Chen pairwise Force calculation.
533 gezelter 762 subroutine do_sc_pair(atom1, atom2, d, rij, r2, rcut, sw, vpair, fpair, &
534 chuckv 702 pot, f, do_pot)
535     !Arguments
536     integer, intent(in) :: atom1, atom2
537 gezelter 762 real( kind = dp ), intent(in) :: rij, r2, rcut
538 chuckv 702 real( kind = dp ) :: pot, sw, vpair
539     real( kind = dp ), dimension(3,nLocal) :: f
540     real( kind = dp ), intent(in), dimension(3) :: d
541     real( kind = dp ), intent(inout), dimension(3) :: fpair
542    
543     logical, intent(in) :: do_pot
544    
545     real( kind = dp ) :: drdx,drdy,drdz
546 chuckv 728 real( kind = dp ) :: dvpdr
547     real( kind = dp ) :: drhodr
548 chuckv 702 real( kind = dp ) :: dudr
549 chuckv 714 real( kind = dp ) :: rcij
550 chuckv 702 real( kind = dp ) :: drhoidr,drhojdr
551     real( kind = dp ) :: Fx,Fy,Fz
552     real( kind = dp ) :: r,d2pha,phb,d2phb
553 chuckv 728 real( kind = dp ) :: pot_temp,vptmp
554     real( kind = dp ) :: epsilonij,aij,nij,mij,vcij
555 chuckv 702 integer :: id1,id2
556     integer :: mytype_atom1
557     integer :: mytype_atom2
558     integer :: atid1,atid2
559     !Local Variables
560    
561     ! write(*,*) "Frho: ", Frho(atom1)
562 chuckv 835
563     cleanArrays = .true.
564 chuckv 702
565     dvpdr = 0.0E0_DP
566    
567    
568     #ifdef IS_MPI
569     atid1 = atid_row(atom1)
570     atid2 = atid_col(atom2)
571     #else
572     atid1 = atid(atom1)
573     atid2 = atid(atom2)
574     #endif
575    
576 chuckv 728 mytype_atom1 = SCList%atidToSCType(atid1)
577     mytype_atom2 = SCList%atidTOSCType(atid2)
578 chuckv 702
579     drdx = d(1)/rij
580     drdy = d(2)/rij
581     drdz = d(3)/rij
582    
583 chuckv 714
584     epsilonij = MixingMap(mytype_atom1,mytype_atom2)%epsilon
585     aij = MixingMap(mytype_atom1,mytype_atom2)%alpha
586     nij = MixingMap(mytype_atom1,mytype_atom2)%n
587     mij = MixingMap(mytype_atom1,mytype_atom2)%m
588     vcij = MixingMap(mytype_atom1,mytype_atom2)%vpair_pot
589 chuckv 702
590 chuckv 728 vptmp = epsilonij*((aij/r)**nij)
591 chuckv 702
592    
593 chuckv 714 dvpdr = -nij*vptmp/r
594     drhodr = -mij*((aij/r)**mij)/r
595 chuckv 728
596 chuckv 714
597 chuckv 728 dudr = drhodr*(dfrhodrho(atom1)+dfrhodrho(atom2)) &
598 chuckv 714 + dvpdr
599 chuckv 728
600     pot_temp = vptmp + vcij
601 chuckv 714
602 chuckv 702
603     #ifdef IS_MPI
604 chuckv 714 dudr = drhodr*(dfrhodrho_row(atom1)+dfrhodrho_col(atom2)) &
605 chuckv 702 + dvpdr
606    
607     #else
608 chuckv 714 dudr = drhodr*(dfrhodrho(atom1)+dfrhodrho(atom2)) &
609 chuckv 702 + dvpdr
610     #endif
611    
612 chuckv 714
613 chuckv 702 fx = dudr * drdx
614     fy = dudr * drdy
615     fz = dudr * drdz
616    
617    
618     #ifdef IS_MPI
619     if (do_pot) then
620 chuckv 728 pot_Row(METALLIC_POT,atom1) = pot_Row(METALLIC_POT,atom1) + (pot_temp)*0.5
621     pot_Col(METALLIC_POT,atom2) = pot_Col(METALLIC_POT,atom2) + (pot_temp)*0.5
622 chuckv 702 end if
623    
624     f_Row(1,atom1) = f_Row(1,atom1) + fx
625     f_Row(2,atom1) = f_Row(2,atom1) + fy
626     f_Row(3,atom1) = f_Row(3,atom1) + fz
627    
628     f_Col(1,atom2) = f_Col(1,atom2) - fx
629     f_Col(2,atom2) = f_Col(2,atom2) - fy
630     f_Col(3,atom2) = f_Col(3,atom2) - fz
631     #else
632    
633     if(do_pot) then
634 chuckv 728 pot = pot + pot_temp
635 chuckv 702 end if
636    
637     f(1,atom1) = f(1,atom1) + fx
638     f(2,atom1) = f(2,atom1) + fy
639     f(3,atom1) = f(3,atom1) + fz
640    
641     f(1,atom2) = f(1,atom2) - fx
642     f(2,atom2) = f(2,atom2) - fy
643     f(3,atom2) = f(3,atom2) - fz
644     #endif
645    
646 chuckv 728
647 chuckv 702 #ifdef IS_MPI
648     id1 = AtomRowToGlobal(atom1)
649     id2 = AtomColToGlobal(atom2)
650     #else
651     id1 = atom1
652     id2 = atom2
653     #endif
654    
655     if (molMembershipList(id1) .ne. molMembershipList(id2)) then
656    
657     fpair(1) = fpair(1) + fx
658     fpair(2) = fpair(2) + fy
659     fpair(3) = fpair(3) + fz
660    
661     endif
662    
663    
664 chuckv 728 end subroutine do_sc_pair
665 chuckv 702
666    
667    
668 chuckv 713 end module suttonchen