| 1 |
module long_range_forces |
| 2 |
use definitions, ONLY : dp, ndim |
| 3 |
use simulation |
| 4 |
#ifdef MPI |
| 5 |
use mpi_force_module |
| 6 |
#endif |
| 7 |
implicit none |
| 8 |
PRIVATE |
| 9 |
|
| 10 |
type, public :: ForceSelecter |
| 11 |
sequence |
| 12 |
|
| 13 |
logical :: is_dipole |
| 14 |
logical :: is_vdw |
| 15 |
logical :: is_lj |
| 16 |
logical :: is_ssd |
| 17 |
|
| 18 |
end type ForceSelecter |
| 19 |
|
| 20 |
|
| 21 |
real( kind = dp ) :: rlistsq |
| 22 |
real( kind = dp ) :: rcutsq |
| 23 |
|
| 24 |
|
| 25 |
|
| 26 |
|
| 27 |
integer, allocatable, dimension(:) :: point |
| 28 |
integer, allocatable, dimension(:) :: list |
| 29 |
|
| 30 |
|
| 31 |
|
| 32 |
|
| 33 |
contains |
| 34 |
|
| 35 |
|
| 36 |
subroutine long_range_force(nComponents,nDim,q,f,t,rF,A,TotPE) |
| 37 |
|
| 38 |
!-------------------- arguments--------------------------> |
| 39 |
! integer components |
| 40 |
integer, intent(in) :: nComponents ! number of Particles |
| 41 |
integer, intent(in) :: nDim ! number of dimensions |
| 42 |
|
| 43 |
! real scalars |
| 44 |
real( kind = dp ), intent(out) :: TotPE ! potential energy |
| 45 |
|
| 46 |
! real vectors |
| 47 |
real( kind = dp ),dimension(nDim,nComponents), & |
| 48 |
intent(inout) :: q ! position vector |
| 49 |
real( kind = dp ),dimension(nDim,nComponents), & |
| 50 |
intent(inout) :: f ! force vector |
| 51 |
real( kind = dp ),dimension(nDim,nComponents), & |
| 52 |
intent(inout) :: t ! torque vector |
| 53 |
real( kind = dp ),dimension(nDim,nComponents), & |
| 54 |
intent(inout) :: rF ! reaction field vector |
| 55 |
real( kind = dp ),dimension(nDim,nDim), & |
| 56 |
intent(inout) :: A ! rotation matrix |
| 57 |
!------------------- end arguments-------------------------> |
| 58 |
|
| 59 |
|
| 60 |
!------------------- local variables-----------------------> |
| 61 |
real( kind = dp ), dimension(nDim) :: q_i |
| 62 |
|
| 63 |
|
| 64 |
|
| 65 |
|
| 66 |
|
| 67 |
|
| 68 |
|
| 69 |
!!$ |
| 70 |
!!$ subroutine long_range_force ( check_exclude, & |
| 71 |
!!$ pair_i, pair_j, n_pairs, natoms, sigma, epslon, & |
| 72 |
!!$ box, & |
| 73 |
!!$ rx, ry, rz, fx, fy, fz, & |
| 74 |
!!$ v, & |
| 75 |
!!$ update, point, list, maxnab, & |
| 76 |
!!$ rx0, ry0, rz0, & |
| 77 |
!!$ ux, uy, uz, & |
| 78 |
!!$ tx, ty, tz, & |
| 79 |
!!$ ex, ey, ez, & |
| 80 |
!!$ mu, rrf, rtaper, & |
| 81 |
!!$ dielectric, & |
| 82 |
!!$ is_dipole, is_vdw, is_lj, is_ssd, & |
| 83 |
!!$ Axx, Axy, Axz, & |
| 84 |
!!$ Ayx, Ayy, Ayz, & |
| 85 |
!!$ Azx, Azy, Azz ) |
| 86 |
|
| 87 |
|
| 88 |
|
| 89 |
! This routine implements the Verlet neighbor list for all of |
| 90 |
! the long range force calculations. After a pair has been |
| 91 |
! determined to lie within the neighbor list, the pair is passed |
| 92 |
! to the appropriate force functions. |
| 93 |
|
| 94 |
!!$ |
| 95 |
!!$ |
| 96 |
!!$ ! Passed Arguments |
| 97 |
!!$ |
| 98 |
!!$ integer :: n_pairs ! the number of excluded pairs |
| 99 |
!!$ integer :: natoms ! the number of atoms in the system |
| 100 |
!!$ integer :: maxnab ! the max number of neighbors for the verlet list |
| 101 |
!!$ |
| 102 |
!!$ logical(kind=2) :: check_exclude ! boolean to check for exclusion pairs |
| 103 |
!!$ logical(kind=2) :: update ! boolean to update the neighbor list |
| 104 |
!!$ |
| 105 |
!!$ double precision rcut ! the VDW/LJ cutoff radius |
| 106 |
!!$ double precision rlist ! Verlet list cutoff |
| 107 |
!!$ double precision box_x, box_y, box_z ! periodic boundry conditions |
| 108 |
!!$ double precision rrf ! dipole reaction field cutoff |
| 109 |
!!$ double precision rtaper ! the taper radius of the rxn field |
| 110 |
!!$ double precision dielectric ! the dielectric cnst. of the rxn field |
| 111 |
!!$ double precision v ! the potential energy |
| 112 |
!!$ |
| 113 |
!!$ |
| 114 |
!!$ |
| 115 |
!!$ ! Passed Arrays |
| 116 |
!!$ |
| 117 |
!!$ integer, dimension(n_pairs):: pair_i, pair_j ! the excluded pairs i and j |
| 118 |
!!$ integer, dimension(natoms) :: point ! the Verlet list ptr array |
| 119 |
!!$ integer, dimension(maxnab) :: list ! the verlet list |
| 120 |
!!$ |
| 121 |
!!$ logical(kind=2), dimension(natoms) :: is_dipole ! dipole boolean array |
| 122 |
!!$ logical(kind=2), dimension(natoms) :: is_vdw ! VDW boolean array |
| 123 |
!!$ logical(kind=2), dimension(natoms) :: is_lj ! LJ boolean array |
| 124 |
!!$ logical(kind=2), dimension(natoms) :: is_ssd ! ssd boolean array |
| 125 |
!!$ |
| 126 |
!!$ double precision, dimension(natoms) :: sigma ! VDW/LJ distance prmtr. |
| 127 |
!!$ double precision, dimension(natoms) :: epslon ! VDW/LJ well depth prmtr. |
| 128 |
!!$ double precision, dimension(natoms) :: rx, ry, rz ! positions |
| 129 |
!!$ double precision, dimension(natoms) :: fx, fy, fz ! forces |
| 130 |
!!$ double precision, dimension(natoms) :: rx0, ry0, rz0 ! intial verlet positions |
| 131 |
!!$ double precision, dimension(natoms) :: ux, uy, uz ! dipole unit vectors |
| 132 |
!!$ double precision, dimension(natoms) :: tx, ty, tz ! torsions |
| 133 |
!!$ double precision, dimension(natoms) :: ex, ey, ez ! reacion field |
| 134 |
!!$ double precision, dimension(natoms) :: mu ! dipole moments |
| 135 |
!!$ double precision, dimension(natoms) :: Axx, Axy, Axz ! rotational array |
| 136 |
!!$ double precision, dimension(natoms) :: Ayx, Ayy, Ayz ! |
| 137 |
!!$ double precision, dimension(natoms) :: Azx, Azy, Azz ! |
| 138 |
!!$ |
| 139 |
!!$ ! local variables |
| 140 |
!!$ |
| 141 |
!!$ double precision rxi, ryi, rzi |
| 142 |
!!$ double precision rcutsq, rlstsq, rrfsq, rijsq, rij |
| 143 |
!!$ double precision rxij, ryij, rzij |
| 144 |
!!$ double precision prerf ! a reaction field preterm |
| 145 |
!!$ |
| 146 |
!!$ double precision, dimension(9,natoms) :: A |
| 147 |
!!$ |
| 148 |
!!$ integer :: i, j, k, ix, jx, nlist |
| 149 |
!!$ integer :: jbeg, jend, jnab |
| 150 |
!!$ |
| 151 |
!!$ logical :: exclude_temp1, exclude_temp2, exclude |
| 152 |
|
| 153 |
|
| 154 |
!******************************************************************* |
| 155 |
!!$ |
| 156 |
!!$ do i=1, natoms |
| 157 |
!!$ A(1,i) = Axx(i) |
| 158 |
!!$ A(2,i) = Axy(i) |
| 159 |
!!$ A(3,i) = Axz(i) |
| 160 |
!!$ |
| 161 |
!!$ A(4,i) = Ayx(i) |
| 162 |
!!$ A(5,i) = Ayy(i) |
| 163 |
!!$ A(6,i) = Ayz(i) |
| 164 |
!!$ |
| 165 |
!!$ A(7,i) = Azx(i) |
| 166 |
!!$ A(8,i) = Azy(i) |
| 167 |
!!$ A(9,i) = Azz(i) |
| 168 |
!!$ end do |
| 169 |
|
| 170 |
|
| 171 |
rlstsq = rlist * rlist |
| 172 |
rcutsq = rcut * rcut |
| 173 |
rrfsq = rrf * rrf |
| 174 |
|
| 175 |
prerf = 14.39257d0 * 2.0d0 * ( dielectric - 1.0d0 ) / & |
| 176 |
( ( 2.0d0 * dielectric + 1.0d0 ) * rrfsq * rrf ) |
| 177 |
|
| 178 |
|
| 179 |
! ** zero forces ** |
| 180 |
f = 0.0_dp |
| 181 |
t = 0.0_dp |
| 182 |
rF = 0.0_dp |
| 183 |
|
| 184 |
TotPE = 0.0_dp |
| 185 |
|
| 186 |
|
| 187 |
|
| 188 |
if ( update ) then |
| 189 |
|
| 190 |
|
| 191 |
! ** save current configuration, construct ** |
| 192 |
! ** neighbour list and calculate forces ** |
| 193 |
|
| 194 |
call long_range_save(natoms,rx,ry,rz,rx0,ry0,rz0) |
| 195 |
|
| 196 |
nlist = 0 |
| 197 |
|
| 198 |
do i = 1, natoms - 1 |
| 199 |
|
| 200 |
point(i) = nlist + 1 |
| 201 |
|
| 202 |
q_i(1:nDim) = q(1:ndim,i) |
| 203 |
|
| 204 |
rxi = rx(i) |
| 205 |
ryi = ry(i) |
| 206 |
rzi = rz(i) |
| 207 |
|
| 208 |
do j = i + 1, natoms |
| 209 |
|
| 210 |
rxij = rx(j) - rxi |
| 211 |
ryij = ry(j) - ryi |
| 212 |
rzij = rz(j) - rzi |
| 213 |
|
| 214 |
exclude = .false. |
| 215 |
|
| 216 |
if( check_exclude ) then |
| 217 |
|
| 218 |
do k = 1, n_pairs |
| 219 |
|
| 220 |
! add 1 for c -> fortran indexing |
| 221 |
ix = pair_i(k) + 1 |
| 222 |
jx = pair_j(k) + 1 |
| 223 |
exclude_temp1 = (i.eq.ix).and.(j.eq.jx) |
| 224 |
exclude_temp2 = (i.eq.jx).and.(j.eq.ix) |
| 225 |
|
| 226 |
if(exclude_temp1.or.exclude_temp2) then |
| 227 |
|
| 228 |
exclude = .true. |
| 229 |
endif |
| 230 |
enddo |
| 231 |
endif |
| 232 |
|
| 233 |
if(.not.exclude) then |
| 234 |
|
| 235 |
rxij = rxij - box_x * dsign( 1.0d0, rxij ) & |
| 236 |
* int( (dabs( rxij / box_x ) + 0.5d0) ) |
| 237 |
ryij = ryij - box_y * dsign( 1.0d0, ryij ) & |
| 238 |
* int( (dabs( ryij / box_y ) + 0.5d0) ) |
| 239 |
rzij = rzij - box_z * dsign( 1.0d0, rzij ) & |
| 240 |
* int( (dabs( rzij / box_z ) + 0.5d0) ) |
| 241 |
|
| 242 |
rijsq = rxij * rxij + ryij * ryij + rzij * rzij |
| 243 |
|
| 244 |
if ( rijsq .lt. rlstsq ) then |
| 245 |
|
| 246 |
nlist = nlist + 1 |
| 247 |
list(nlist) = j |
| 248 |
|
| 249 |
! ** remove this check if maxnab is appropriate ** |
| 250 |
|
| 251 |
if ( nlist .eq. maxnab ) then |
| 252 |
write(*,*) i, j, nlist, maxnab, rijsq, rlstsq |
| 253 |
stop 'list too small' |
| 254 |
endif |
| 255 |
|
| 256 |
if ( rijsq .lt. rcutsq ) then |
| 257 |
|
| 258 |
if ( is_vdw(i) .and. is_vdw(j) ) then |
| 259 |
call force_VDW( i, j, rcutsq, rijsq, sigma, epslon, & |
| 260 |
v, fx, fy, fz, rxij, ryij, rzij, natoms ) |
| 261 |
endif |
| 262 |
|
| 263 |
if ( is_lj(i) .and. is_lj(j) ) then |
| 264 |
call force_lj( i, j, rcutsq, rijsq, sigma, epslon, v, & |
| 265 |
fx, fy, fz, rxij, ryij, rzij, natoms ) |
| 266 |
endif |
| 267 |
|
| 268 |
if( is_ssd(i) .and. is_ssd(j) ) then |
| 269 |
|
| 270 |
rij = dsqrt(rijsq); |
| 271 |
|
| 272 |
call ssd_forces( natoms, i, j, i, j, rxij, ryij, rzij, & |
| 273 |
rij, v, rijsq, fx, fy, fz, tx, ty, tz, A ) |
| 274 |
end if |
| 275 |
|
| 276 |
endif |
| 277 |
|
| 278 |
if( is_dipole(i) .and. is_dipole(j) ) then |
| 279 |
if( rijsq .lt. rrfsq ) then |
| 280 |
|
| 281 |
call dipole_rf( i, j, rrfsq, rijsq, v, rxij, ryij, & |
| 282 |
rzij, rrf, dielectric, rtaper, natoms, & |
| 283 |
ux, uy, uz, mu, fx, fy, fz, tx, ty, tz, & |
| 284 |
ex, ey, ez, prerf ) |
| 285 |
endif |
| 286 |
end if |
| 287 |
endif |
| 288 |
endif |
| 289 |
|
| 290 |
enddo |
| 291 |
|
| 292 |
end do |
| 293 |
|
| 294 |
point(natoms) = nlist + 1 |
| 295 |
|
| 296 |
else |
| 297 |
|
| 298 |
|
| 299 |
!** use the list to find the neighbours ** |
| 300 |
|
| 301 |
do i = 1, natoms - 1 |
| 302 |
|
| 303 |
jbeg = point(i) |
| 304 |
jend = point(i+1) - 1 |
| 305 |
|
| 306 |
!** check that atom i has neighbours ** |
| 307 |
|
| 308 |
if( jbeg .le. jend ) then |
| 309 |
|
| 310 |
rxi = rx(i) |
| 311 |
ryi = ry(i) |
| 312 |
rzi = rz(i) |
| 313 |
|
| 314 |
do jnab = jbeg, jend |
| 315 |
|
| 316 |
j = list(jnab) |
| 317 |
|
| 318 |
rxij = rx(j) - rxi |
| 319 |
ryij = ry(j) - ryi |
| 320 |
rzij = rz(j) - rzi |
| 321 |
|
| 322 |
rxij = rxij - box_x * dsign( 1.0d0, rxij ) & |
| 323 |
* int( dabs( rxij / box_x ) + 0.5d0 ) |
| 324 |
ryij = ryij - box_y * dsign( 1.0d0, ryij ) & |
| 325 |
* int( dabs( ryij / box_y ) + 0.5d0 ) |
| 326 |
rzij = rzij - box_z * dsign( 1.0d0, rzij ) & |
| 327 |
* int( dabs( rzij / box_z ) + 0.5d0 ) |
| 328 |
|
| 329 |
rijsq = rxij * rxij + ryij * ryij + rzij * rzij |
| 330 |
|
| 331 |
if ( rijsq .lt. rcutsq ) then |
| 332 |
|
| 333 |
if ( is_vdw(i) .and. is_vdw(j) ) then |
| 334 |
call force_VDW( i, j, rcutsq, rijsq, sigma, epslon, & |
| 335 |
v, fx, fy, fz, rxij, ryij, rzij, natoms ) |
| 336 |
endif |
| 337 |
|
| 338 |
if ( is_lj(i) .and. is_lj(j) ) then |
| 339 |
call force_lj( i, j, rcutsq, rijsq, sigma, epslon, v, & |
| 340 |
fx, fy, fz, rxij, ryij, rzij, natoms ) |
| 341 |
endif |
| 342 |
|
| 343 |
if( is_ssd(i) .and. is_ssd(j) ) then |
| 344 |
|
| 345 |
rij = dsqrt(rijsq); |
| 346 |
|
| 347 |
call ssd_forces( natoms, i, j, i, j, rxij, ryij, rzij, & |
| 348 |
rij, v, rijsq, fx, fy, fz, tx, ty, tz, A ) |
| 349 |
end if |
| 350 |
|
| 351 |
endif |
| 352 |
|
| 353 |
|
| 354 |
if( is_dipole(i) .and. is_dipole(j) ) then |
| 355 |
if( rijsq .lt. rrfsq ) then |
| 356 |
|
| 357 |
call dipole_rf( i, j, rrfsq, rijsq, v, rxij, ryij, & |
| 358 |
rzij, rrf, dielectric, rtaper, natoms, & |
| 359 |
ux, uy, uz, mu, fx, fy, fz, tx, ty, tz, & |
| 360 |
ex, ey, ez, prerf ) |
| 361 |
endif |
| 362 |
endif |
| 363 |
|
| 364 |
end do |
| 365 |
endif |
| 366 |
end do |
| 367 |
endif |
| 368 |
|
| 369 |
! calculate the reaction field effect |
| 370 |
|
| 371 |
!!$ call reaction_field( v, prerf, natoms, mu, ux, uy, uz, tx, ty, tz, & |
| 372 |
!!$ ex, ey, ez, is_dipole ) |
| 373 |
|
| 374 |
|
| 375 |
end subroutine long_range_force |
| 376 |
|
| 377 |
|
| 378 |
|
| 379 |
subroutine long_range_check ( rcut, rlist, update, natoms, & |
| 380 |
rx,ry,rz,rx0,ry0,rz0) |
| 381 |
|
| 382 |
|
| 383 |
!******************************************************************* |
| 384 |
!** decides whether the list needs to be reconstructed. ** |
| 385 |
!** ** |
| 386 |
!** principal variables: ** |
| 387 |
!** ** |
| 388 |
!** real rx(n),ry(n),rz(n) atom positions ** |
| 389 |
!** real rx0(n),ry0(n),rz0(n) coordinates at last update ** |
| 390 |
!** real rlist radius of verlet list ** |
| 391 |
!** real rcut cutoff distance for forces ** |
| 392 |
!** real dispmx largest displacement ** |
| 393 |
!** integer n number of atoms ** |
| 394 |
!** logical update if true the list is updated ** |
| 395 |
!** ** |
| 396 |
!** usage: ** |
| 397 |
!** ** |
| 398 |
!** check is called to set update before every call to force. ** |
| 399 |
!******************************************************************* |
| 400 |
|
| 401 |
|
| 402 |
! Passed variables |
| 403 |
|
| 404 |
integer :: natoms |
| 405 |
|
| 406 |
logical(kind=2) :: update |
| 407 |
|
| 408 |
double precision rcut, rlist |
| 409 |
|
| 410 |
! Passed arrays |
| 411 |
double precision, dimension(natoms) :: rx, ry, rz |
| 412 |
double precision, dimension(natoms) :: rx0, ry0, rz0 |
| 413 |
|
| 414 |
! local variables |
| 415 |
|
| 416 |
double precision dispmx |
| 417 |
|
| 418 |
integer :: i |
| 419 |
|
| 420 |
!******************************************************************* |
| 421 |
|
| 422 |
!** calculate maximum displacement since last update ** |
| 423 |
|
| 424 |
dispmx = 0.0d0 |
| 425 |
|
| 426 |
do i = 1, natoms |
| 427 |
|
| 428 |
!write(*,*) 'calling displacement', i |
| 429 |
|
| 430 |
dispmx = max ( dabs ( rx(i) - rx0(i) ), dispmx ) |
| 431 |
dispmx = max ( dabs ( ry(i) - ry0(i) ), dispmx ) |
| 432 |
dispmx = max ( dabs ( rz(i) - rz0(i) ), dispmx ) |
| 433 |
|
| 434 |
!write(*,*) 'called displacement', i |
| 435 |
|
| 436 |
end do |
| 437 |
|
| 438 |
!** a conservative test of the list skin crossing ** |
| 439 |
|
| 440 |
dispmx = 2.0d0 * dsqrt ( 3.0d0 * dispmx ** 2 ) |
| 441 |
|
| 442 |
update = ( dispmx .gt. ( rlist - rcut ) ) |
| 443 |
|
| 444 |
|
| 445 |
return |
| 446 |
end subroutine long_range_check |
| 447 |
|
| 448 |
|
| 449 |
|
| 450 |
subroutine long_range_save(natoms,rx,ry,rz,rx0,ry0,rz0) |
| 451 |
|
| 452 |
|
| 453 |
!******************************************************************* |
| 454 |
!** saves current configuration for future checking. ** |
| 455 |
!** ** |
| 456 |
!** principal variables: ** |
| 457 |
!** ** |
| 458 |
!** real rx(n),ry(n),rz(n) atom positions ** |
| 459 |
!** real rx0(n),ry0(n),rz0(n) storage locations for save ** |
| 460 |
!** integer n number of atoms ** |
| 461 |
!** ** |
| 462 |
!** usage: ** |
| 463 |
!** ** |
| 464 |
!** save is called whenever the new verlet list is constructed. ** |
| 465 |
!******************************************************************* |
| 466 |
|
| 467 |
integer :: i |
| 468 |
|
| 469 |
integer :: natoms |
| 470 |
|
| 471 |
double precision, dimension(natoms) :: rx, ry, rz |
| 472 |
double precision, dimension(natoms) :: rx0, ry0, rz0 |
| 473 |
|
| 474 |
!******************************************************************* |
| 475 |
|
| 476 |
do i = 1, natoms |
| 477 |
|
| 478 |
rx0(i) = rx(i) |
| 479 |
ry0(i) = ry(i) |
| 480 |
rz0(i) = rz(i) |
| 481 |
|
| 482 |
end do |
| 483 |
|
| 484 |
return |
| 485 |
end subroutine long_range_save |
| 486 |
|
| 487 |
end module long_range_forces |
