Line data Source code
1 : !!****m* ABINIT/m_relaxpol
2 : !! NAME
3 : !! m_relaxpol
4 : !!
5 : !! FUNCTION
6 : !!
7 : !! COPYRIGHT
8 : !! Copyright (C) 1999-2026 ABINIT group (MVeithen)
9 : !! This file is distributed under the terms of the
10 : !! GNU General Public License, see ~abinit/COPYING
11 : !! or http://www.gnu.org/copyleft/gpl.txt .
12 : !!
13 : !! SOURCE
14 :
15 : #if defined HAVE_CONFIG_H
16 : #include "config.h"
17 : #endif
18 :
19 : #include "abi_common.h"
20 :
21 : module m_relaxpol
22 :
23 : use defs_basis
24 : use m_abicore
25 : use m_errors
26 :
27 : use m_fstrings, only : sjoin, itoa
28 : use m_matrix, only : matr3inv
29 : use m_berrytk, only : polcart
30 : use m_hide_lapack, only : dzgedi, dzgefa
31 : use m_geometry, only : xcart2xred
32 : use m_dynmat, only : symdyma
33 : use m_crystal, only : crystal_t
34 :
35 : implicit none
36 :
37 : private
38 : !!***
39 :
40 : public :: relaxpol
41 : !!***
42 :
43 : contains
44 : !!***
45 :
46 : !!****f* ABINIT/relaxpol
47 : !! NAME
48 : !! relaxpol
49 : !!
50 : !! FUNCTION
51 : !! 1) Compute polarization in cartesian coordinates
52 : !! 2) Structural relaxation at fixed polarization: this routine
53 : !! solves the linear system of equations Eq.(13)
54 : !! of Na Sai et al., PRB 66, 104108 (2002) [[cite:Sai2002]].
55 : !!
56 : !! INPUTS
57 : !! blkflg(msize) = flag for every matrix element (0=> the element
58 : !! is not in the data block), (1=> the element is in the data blok)
59 : !! blkval(2,msize) = matrix that contains the second-order energy derivatives
60 : !! etotal = Kohn-Sham energy at zero electric field
61 : !! gred(3,natom) = -1 times the forces in reduced coordinates
62 : !! iatfix(natom) = indices of the atoms that are held fixed in the relaxation
63 : !! iout = unit number for output
64 : !! istrfix(6) = indices of the elements of the strain tensor that
65 : !! are held fixed in the relaxation
66 : !! 1 = xx
67 : !! 2 = yy
68 : !! 3 = zz
69 : !! 4 = yz & zy
70 : !! 5 = xz & zx
71 : !! 6 = xy & yx
72 : !! mpert = maximum number of ipert
73 : !! msize = dimension of blkflg and blkval
74 : !! natfix = number of atoms that are held fixed in the relaxation
75 : !! natom = number of atoms in the unit cell
76 : !! nstrfix = number of elements of the strain tensor that are held fixed in the relaxation
77 : !! pel(3) = electronic polarization not taking into account the factor 1/ucvol
78 : !! red_ptot(3) = total polarization reduced units !!REC
79 : !! relaxat = 1: relax atomic positions
80 : !! = 0: do not relax atomic positions
81 : !! relaxstr = 1: relax cell parameters
82 : !! = 0: do not relax cell parameters
83 : !! strten(6) = stress tensor in cartesian coordinates
84 : !! targetpol(3) = target value of the polarization
85 : !!
86 : !! OUTPUT
87 : !!
88 : !! NOTES
89 : !! - The elements of the dynamical matrix stored in blkval
90 : !! are symmetrized before computing the new atomic positions and cell parameters.
91 : !! - In case relaxat = 0 and relaxstr = 0, the routine only
92 : !! computes the polarization in cartesian coordinates.
93 : !!
94 : !! SOURCE
95 :
96 3 : subroutine relaxpol(Crystal,blkflg,blkval,etotal,gred,iatfix,iout,istrfix,&
97 : & mpert,msize,natfix,natom,nstrfix,pel,red_ptot,relaxat,relaxstr,&
98 : & strten,targetpol)
99 :
100 : !Arguments -------------------------------
101 : !scalars
102 : integer,intent(in) :: iout,mpert,msize,natfix,natom,nstrfix
103 : integer,intent(in) :: relaxat,relaxstr
104 : real(dp),intent(in) :: etotal
105 : type(crystal_t),intent(in) :: Crystal
106 : !arrays
107 : integer,intent(in) :: blkflg(msize),iatfix(natom)
108 : integer,intent(in) :: istrfix(6)
109 : real(dp),intent(in) :: gred(3,natom),pel(3),strten(6)
110 : real(dp),intent(in) :: red_ptot(3)
111 : real(dp),intent(inout) :: blkval(2,msize),targetpol(3)
112 :
113 : !Local variables -------------------------
114 : !scalars
115 : integer :: flag,iatom,idir,ii,index,index1,index_tild,info,ipert,istrain
116 : integer :: itypat,jdir,job,jpert,polunit,posi,posj,sizef
117 : integer :: usepaw
118 : logical :: iwrite
119 : real(dp) :: e1,fmax,poltmp,sigmax,tol,value,ucvol
120 : character(len=500) :: message
121 : !arrays
122 : integer :: irelaxstrain(6)
123 3 : integer,allocatable :: ipvt(:),irelaxat(:),rfpert(:,:)
124 6 : real(dp) :: acell_new(3),delta_eta(6),delta_xcart(3,natom),det(2,2),diffpol(3),rprimd(3,3)
125 : real(dp) :: diffsig(6),favg(3),gprimd(3,3),lambda(3),pel_cart(3),pelev(3)
126 : real(dp) :: pion(3),pion_cart(3),ptot_cart(3),qphon(3),rprim(3,3)
127 : real(dp) :: rprimd_new(3,3),sigelfd(6),strainmat(3,3)
128 6 : real(dp) :: xcart_new(3,natom),xred_new(3,natom)
129 3 : real(dp),allocatable :: cfac(:,:),delta(:),dymati(:),fcart(:,:),fcmat(:,:,:)
130 3 : real(dp),allocatable :: fdiff(:,:),felfd(:,:),ifcmat(:,:,:),vec(:),zgwork(:,:)
131 :
132 : ! *********************************************************************
133 :
134 3 : usepaw = 0
135 39 : rprimd = Crystal%rprimd
136 3 : ucvol = Crystal%ucvol
137 3 : iwrite = iout > 0
138 :
139 : !Check if some degrees of freedom remain fixed during the optimization
140 :
141 9 : ABI_MALLOC(irelaxat,(natom))
142 30 : irelaxat(:) = 1 ; irelaxstrain(:) = 1
143 3 : if (natfix > 0) then
144 0 : do ii = 1, natfix
145 0 : iatom = iatfix(ii)
146 0 : if ((iatom > natom).or.(iatom < 0)) then
147 : write(message, '(a,i0,a,i0,a,a,a,a,a)')&
148 0 : & 'The value of iatfix(',ii,') is ',iatom,', which is not allowed.',ch10,&
149 0 : & 'iatfix must be larger than 0 and smaller than natom.',ch10,&
150 0 : & 'Action: correct iatfix in your input file.'
151 0 : ABI_ERROR(message)
152 : end if
153 0 : irelaxat(iatom) = 0
154 : end do
155 : end if
156 :
157 3 : if (nstrfix > 0) then
158 3 : do ii = 1, nstrfix
159 2 : istrain = istrfix(ii)
160 2 : if ((istrain > 6).or.(istrain < 0)) then
161 : write(message, '(a,i0,a,i0,a,a,a,a,a)')&
162 0 : & 'istrfix(',ii,') is',istrain,', which is not allowed.',ch10,&
163 0 : & 'istrfix must be larger than 0 and smaller than 6.',ch10,&
164 0 : & 'Action : correct istrfix in your input file.'
165 0 : ABI_ERROR(message)
166 : end if
167 3 : irelaxstrain(istrain) = 0
168 : end do
169 : end if
170 :
171 :
172 9 : ABI_MALLOC(rfpert,(mpert,3))
173 12 : ABI_MALLOC(cfac,(mpert,mpert))
174 3 : call matr3inv(rprimd,gprimd)
175 :
176 : !Compute the size of the matrix that contains the second-order derivatives
177 :
178 3 : sizef = 3
179 165 : rfpert(:,:) = 0
180 12 : rfpert(natom+2,1:3) = 1
181 3 : if (relaxat == 1) then
182 9 : do iatom = 1, natom
183 9 : if (irelaxat(iatom) == 1) then
184 7 : sizef = sizef + 3
185 28 : rfpert(iatom,1:3) = 1
186 : end if
187 : end do
188 : end if
189 3 : ii = natom + 2
190 3 : if (relaxstr == 1) then
191 2 : istrain = 0
192 6 : do ipert = (natom+3), (natom+4)
193 18 : do idir = 1, 3
194 12 : istrain = istrain + 1
195 16 : if (irelaxstrain(istrain) == 1) then
196 10 : sizef = sizef + 1
197 10 : rfpert(ipert,idir) = 1
198 : end if
199 : end do
200 : end do
201 : end if
202 :
203 12 : ABI_MALLOC(fcmat,(2,sizef,sizef))
204 9 : ABI_MALLOC(ifcmat,(2,sizef,sizef))
205 9 : ABI_MALLOC(vec,(sizef))
206 6 : ABI_MALLOC(delta,(sizef))
207 9 : ABI_MALLOC(ipvt,(sizef))
208 9 : ABI_MALLOC(zgwork,(2,sizef))
209 9 : ABI_MALLOC(fcart,(3,natom))
210 6 : ABI_MALLOC(felfd,(3,natom))
211 6 : ABI_MALLOC(fdiff,(3,natom))
212 :
213 : !Build the vector that stores the forces, sigma and the polarization
214 :
215 43 : vec(:) = zero
216 3 : posi = 0
217 :
218 3 : if (relaxat == 1) then
219 :
220 : ! Note conversion to cartesian coordinates (bohr) AND
221 : ! negation to make a force out of a gradient
222 : ! Also subtract off average force from each force
223 : ! component to avoid spurious drifting of atoms across cell.
224 2 : favg(:) = zero
225 9 : do iatom = 1, natom
226 30 : do idir = 1, 3
227 : fcart(idir,iatom) = -(gprimd(idir,1)*gred(1,iatom) + &
228 : & gprimd(idir,2)*gred(2,iatom) + &
229 21 : & gprimd(idir,3)*gred(3,iatom))
230 28 : favg(idir) = favg(idir) + fcart(idir,iatom)
231 : end do
232 : end do
233 8 : favg(:) = favg(:)/dble(natom)
234 9 : do iatom = 1, natom
235 30 : fcart(:,iatom) = fcart(:,iatom) - favg(:)
236 : end do
237 :
238 9 : do iatom = 1, natom
239 9 : if (irelaxat(iatom) == 1) then
240 28 : do idir = 1, 3
241 21 : posi = posi + 1
242 28 : vec(posi) = fcart(idir,iatom)
243 : end do
244 : end if
245 : end do
246 :
247 : end if ! relaxat == 1
248 :
249 : !DEBUG
250 : !write(std_out,*)'Forces in cartesian coords'
251 : !do iatom = 1, natom
252 : !write(std_out,'(3(2x,e16.9))')(fcart(idir,iatom),idir = 1, 3)
253 : !end do
254 : !stop
255 : !ENDDEBUG
256 :
257 : !Transform target polarization to atomic units
258 12 : targetpol(:) = targetpol(:)*((Bohr_Ang*1.0d-10)**2)/e_Cb
259 :
260 : !Compute ionic polarization
261 3 : pion(:) = zero
262 12 : do iatom = 1, natom
263 9 : itypat = Crystal%typat(iatom)
264 39 : do idir = 1, 3
265 27 : poltmp = Crystal%zion(itypat) * Crystal%xred(idir,iatom)
266 27 : poltmp = poltmp - two*nint(poltmp/two) ! fold into [-1,1]
267 36 : pion(idir) = pion(idir) + poltmp
268 : end do
269 : end do
270 12 : do idir = 1, 3
271 12 : pion(idir) = pion(idir) - two*nint(pion(idir)/two) ! fold into [-1,1]
272 : end do
273 :
274 : !Transform the polarization to cartesian coordinates
275 3 : polunit = 3
276 3 : pelev=zero ! This is a PAW-related quantity, which we ignore here.
277 : call polcart(red_ptot,pel,pel_cart,pelev,pion,pion_cart,polunit,&
278 3 : & ptot_cart,rprimd,ucvol,iout,usepaw)
279 :
280 12 : do idir = 1, 3
281 9 : posi = posi + 1
282 12 : vec(posi) = ptot_cart(idir) - targetpol(idir)
283 : end do
284 :
285 :
286 3 : if (relaxstr == 1) then
287 14 : do istrain = 1, 6
288 14 : if (irelaxstrain(istrain) == 1) then
289 10 : posi = posi + 1
290 10 : vec(posi) = -1._dp*strten(istrain)*ucvol
291 : end if
292 : end do
293 : end if
294 :
295 :
296 : !Symmetrize the dynamical matrix
297 :
298 9 : ABI_MALLOC(dymati,(2*3*natom*3*natom))
299 : !by the symdyma routine
300 12 : do ipert = 1, natom
301 39 : do idir = 1, 3
302 135 : do jpert = 1, natom
303 423 : do jdir = 1, 3
304 297 : index = jdir +3*((jpert - 1) + mpert*((idir - 1) + 3*(ipert - 1)))
305 297 : index1 = jdir +3*((jpert - 1) + natom*((idir - 1) + 3*(ipert - 1)))
306 297 : dymati(2*index1 - 1) = blkval(1,index)
307 396 : dymati(2*index1 ) = blkval(2,index)
308 : end do
309 : end do
310 : end do
311 : end do
312 :
313 3 : qphon(:) = zero
314 3 : call symdyma(dymati,Crystal%indsym,natom,Crystal%nsym,qphon,rprimd,Crystal%symrel,Crystal%symafm)
315 :
316 12 : do ipert = 1, natom
317 39 : do idir = 1, 3
318 135 : do jpert = 1, natom
319 423 : do jdir = 1, 3
320 297 : index = jdir +3*((jpert - 1) + mpert*((idir - 1) + 3*(ipert - 1)))
321 297 : index1 = jdir +3*((jpert - 1) + natom*((idir - 1) + 3*(ipert - 1)))
322 297 : blkval(1,index) = dymati(2*index1 - 1)
323 396 : blkval(2,index) = dymati(2*index1 )
324 : end do
325 : end do
326 : end do
327 : end do
328 :
329 3 : ABI_FREE(dymati)
330 :
331 : !Define conversion factors for blkval
332 945 : cfac(:,:) = 1._dp
333 12 : cfac(1:natom,natom+2) = -1._dp/ucvol
334 12 : cfac(natom+2,1:natom) = -1._dp/ucvol
335 9 : cfac(natom+3:natom+4,natom+2) = -1._dp
336 9 : cfac(natom+2,natom+3:natom+4) = -1._dp
337 :
338 :
339 : !Build the matrix that contains the second-order derivatives
340 : !ipert = natom + 1 corresponds to the ddk perturbation, that
341 : !is not needed; so skip it
342 :
343 2197 : fcmat(:,:,:) = zero
344 :
345 3 : posi = 0
346 3 : flag = 0
347 : ! When fcmat has been build, flag = 0 if all elements were available.
348 : ! Otherwise, it will be 1. In case one element is missing, check if
349 : ! it can be obtained by changing the order of the perturbations
350 :
351 54 : do ipert = 1, mpert
352 207 : do idir = 1, 3
353 204 : if (rfpert(ipert,idir) == 1) then
354 40 : posi = posi + 1
355 40 : posj = 0
356 :
357 772 : do jpert = 1, mpert
358 2968 : do jdir = 1, 3
359 2928 : if (rfpert(jpert,jdir) == 1) then
360 718 : index = jdir +3*((jpert - 1) + mpert*((idir - 1) + 3*(ipert - 1)))
361 718 : index_tild = idir +3*((ipert - 1) + mpert*((jdir - 1) + 3*(jpert - 1)))
362 718 : posj = posj + 1
363 718 : if ((ipert /= natom + 2).or.(jpert /= natom + 2)) then
364 691 : if (blkflg(index) == 1) then
365 2073 : fcmat(:,posi,posj) = blkval(:,index)*cfac(ipert,jpert)
366 0 : else if (blkflg(index_tild) == 1) then
367 0 : fcmat(:,posi,posj) = blkval(:,index_tild)*cfac(ipert,jpert)
368 0 : blkval(:,index) = blkval(:,index_tild)
369 : else
370 0 : flag = 1
371 0 : write(std_out,'(a,4(2x,i3))')'relaxpol: could not find element:',idir,ipert,jdir,jpert
372 : end if
373 : end if
374 : ! DEBUG
375 : ! write(100,'(4(2x,i3),5x,f16.9)')idir,ipert,jdir,jpert,fcmat(1,posi,posj)
376 : ! ENDDEBUG
377 : end if
378 : end do
379 : end do
380 :
381 : end if
382 : end do
383 : end do
384 :
385 3 : if (flag == 1) then
386 : write(message, '(a,a,a,i0,a,i0,a,a,a,a)' )&
387 0 : & 'Some of the second order derivatives required to deal with the case',ch10,&
388 0 : & 'relaxat = ',relaxat,', relaxstr = ', relaxstr, ch10,&
389 0 : & 'are missing in the DDB.',ch10,&
390 0 : & 'Action: correct your DDB or change your input file.'
391 0 : ABI_ERROR(message)
392 : end if
393 :
394 :
395 : !Compute the inverse of the force constant matrix
396 :
397 3 : if ((relaxat /= 0).or.(relaxstr /= 0)) then
398 :
399 2 : job = 1 ! compute inverse only
400 2166 : ifcmat(:,:,:) = fcmat(:,:,:)
401 :
402 2 : call dzgefa(ifcmat,sizef,sizef,ipvt,info)
403 2 : ABI_CHECK(info == 0, sjoin("dzgefa returned:", itoa(info)))
404 2 : call dzgedi(ifcmat,sizef,sizef,ipvt,det,zgwork,job)
405 :
406 : ! DEBUG
407 : ! write(100,*)'relaxat = ',relaxat
408 : ! write(100,*)'relaxstr = ',relaxstr
409 : ! write(100,*)'irelaxat = '
410 : ! write(100,*)irelaxat(:)
411 : ! write(100,*)'irelaxstrain = '
412 : ! write(100,*)irelaxstrain(:)
413 : ! write(100,*)'sizef = ',sizef
414 : ! write(100,*)'targetpol ='
415 : ! write(100,*)targetpol(:)
416 : ! do ipert = 1, sizef
417 : ! do jpert = 1, sizef
418 : ! write(100,'(2(2x,i3),2x,e16.9)')ipert,jpert,fcmat(1,ipert,jpert)
419 : ! end do
420 : ! end do
421 : ! stop
422 : ! ENDDEBUG
423 :
424 : ! Compute \delta R, \delta \eta and \lambda
425 39 : delta(:) = zero
426 39 : do ipert = 1, sizef
427 748 : do jpert = 1, sizef
428 746 : delta(ipert) = delta(ipert) + ifcmat(1,ipert,jpert)*vec(jpert)
429 : end do
430 : end do
431 :
432 :
433 : ! Update atomic positions
434 2 : posi = 0
435 2 : if (relaxat == 1) then
436 :
437 30 : delta_xcart(:,:) = zero
438 30 : xcart_new(:,:) = zero
439 9 : do iatom = 1, natom
440 9 : if (irelaxat(iatom) == 1) then
441 28 : do idir = 1, 3
442 21 : posi = posi + 1
443 28 : delta_xcart(idir,iatom) = delta(posi)
444 : end do
445 : end if
446 : end do
447 :
448 : ! Drop unsignificant digits in order to eleminate numerical noise
449 2 : tol = 10000000._dp
450 9 : do iatom = 1, natom
451 30 : do idir = 1, 3
452 21 : value = delta_xcart(idir,iatom)
453 21 : ii = log10(abs(value))
454 21 : if (ii <= 0) then
455 21 : ii = abs(ii) + 1
456 21 : value = one*int(tol*value*10.0_dp**ii)/(tol*10.0_dp**ii) !vz_d
457 : else
458 0 : value = one*int(tol*value/(10.0_dp**ii))*(10.0_dp**ii)/tol !vz_d
459 : end if
460 28 : delta_xcart(idir,iatom) = value
461 : end do
462 : end do
463 :
464 30 : xcart_new(:,:) = Crystal%xcart(:,:) + delta_xcart(:,:)
465 2 : call xcart2xred(natom,rprimd,xcart_new,xred_new)
466 : end if ! relaxat == 1
467 :
468 : ! Compute lambda and the value of the energy functional F - \lambda \cdot P$
469 :
470 2 : e1 = etotal
471 8 : do idir = 1, 3
472 6 : posi = posi + 1
473 6 : lambda(idir) = delta(posi)
474 8 : e1 = e1 - lambda(idir)*ptot_cart(idir)
475 : end do
476 :
477 : ! Update cell parameters
478 2 : if (relaxstr == 1) then
479 2 : delta_eta(:) = zero
480 14 : do istrain = 1, 6
481 14 : if (irelaxstrain(istrain) == 1) then
482 10 : posi = posi + 1
483 10 : delta_eta(istrain) = delta(posi)
484 : end if
485 : end do
486 :
487 8 : do istrain = 1, 3
488 8 : strainmat(istrain,istrain) = delta_eta(istrain)
489 : end do
490 2 : strainmat(2,3) = delta_eta(4)/2._dp ; strainmat(3,2) = delta_eta(4)/2._dp
491 2 : strainmat(1,3) = delta_eta(5)/2._dp ; strainmat(3,1) = delta_eta(5)/2._dp
492 2 : strainmat(2,1) = delta_eta(6)/2._dp ; strainmat(1,2) = delta_eta(6)/2._dp
493 :
494 2 : rprimd_new(:,:) = 0._dp
495 8 : do idir = 1, 3
496 26 : do jdir = 1, 3
497 78 : do ii = 1, 3
498 : rprimd_new(jdir,idir) = rprimd_new(jdir,idir) + &
499 72 : & rprimd(ii,idir)*strainmat(ii,jdir)
500 : end do
501 : end do
502 : end do
503 26 : rprimd_new(:,:) = rprimd_new(:,:) + rprimd(:,:)
504 :
505 2 : acell_new(:) = zero
506 8 : do idir = 1, 3
507 24 : do jdir = 1, 3
508 : acell_new(idir) = acell_new(idir) + &
509 24 : & rprimd_new(jdir,idir)*rprimd_new(jdir,idir)
510 : end do
511 6 : acell_new(idir) = sqrt(acell_new(idir))
512 26 : rprim(:,idir) = rprimd_new(:,idir)/acell_new(idir)
513 : end do
514 :
515 : end if ! relaxstr == 1
516 :
517 : ! Write out the results
518 :
519 2 : if (iwrite) then
520 2 : write(iout,*)
521 162 : write(iout,'(a,80a,a)') ch10,('=',ii=1,80),ch10
522 2 : write(iout,*)
523 2 : write(iout,*)'Relaxation of the geometry at fixed polarization:'
524 2 : write(iout,*)
525 2 : write(iout,'(a,3(2x,f16.9))')' Lambda = ',(lambda(idir),idir = 1, 3)
526 2 : write(iout,'(a,e16.9)')' Value of the energy functional E_1 = ',e1
527 2 : write(iout,*)
528 2 : write(iout,*)'Difference between actual value of the Polarization (C/m^2)'
529 2 : write(iout,*)'and the target value:'
530 : end if
531 8 : diffpol(:) = (ptot_cart(:) - targetpol(:))*e_Cb/((Bohr_Ang*1.0d-10)**2)
532 2 : if (iwrite) write(iout,'(3(3x,f16.9))')(diffpol(idir),idir = 1, 3)
533 :
534 2 : if (relaxat == 1) then
535 : ! Compute the forces induced on the atoms by the electric field
536 : ! The strength of the field is determined by lambda
537 30 : felfd(:,:) = zero
538 9 : do iatom = 1, natom
539 30 : do idir = 1, 3
540 91 : do jdir = 1, 3
541 63 : index = idir +3*((iatom - 1) + mpert*((jdir - 1) + 3*(natom + 1)))
542 84 : felfd(idir,iatom) = felfd(idir,iatom) - lambda(jdir)*blkval(1,index)/ucvol
543 : end do
544 : end do
545 : end do
546 :
547 : ! Compute remaining forces and write them out
548 :
549 30 : fdiff(:,:) = fcart(:,:) - felfd(:,:)
550 2 : if (iwrite) then
551 2 : write(iout,*)
552 2 : write(iout,*)'Difference between the Hellmann-Feynman forces'
553 2 : write(iout,*)'and the forces induced by the electric field'
554 2 : write(iout,*)'(cartesian coordinates, hartree/bohr)'
555 : end if
556 2 : fmax = zero
557 9 : do iatom = 1, natom
558 7 : if (iwrite) write(iout,'(3(3x,es16.9))')(fdiff(idir,iatom),idir = 1, 3)
559 30 : do idir = 1, 3
560 28 : if (abs(fdiff(idir,iatom)) > fmax) fmax = abs(fdiff(idir,iatom))
561 : end do
562 : end do
563 :
564 2 : if (iwrite) then
565 2 : write(iout,'(a,3x,es16.9)')' fmax = ',fmax
566 2 : write(iout,*)
567 2 : write(iout,*)'Change of cartesian coordinates (delta_xcart):'
568 9 : do iatom = 1, natom
569 9 : write(iout,'(5x,i3,3(2x,f16.9))')iatom,(delta_xcart(idir,iatom),idir = 1, 3)
570 : end do
571 2 : write(iout,*)
572 2 : write(iout,*)'New cartesian coordinates (xcart_new):'
573 2 : write(iout,*)' xcart'
574 9 : do iatom = 1, natom
575 9 : write(iout,'(3(3x,d22.14))')(xcart_new(idir,iatom),idir = 1, 3)
576 : end do
577 2 : write(iout,*)
578 2 : write(iout,*)'New reduced coordinates (xred_new):'
579 2 : write(iout,*)' xred'
580 9 : do iatom = 1, natom
581 9 : write(iout,'(3(3x,d22.14))')(xred_new(idir,iatom),idir = 1, 3)
582 : end do
583 : end if
584 :
585 : end if ! relaxat == 1
586 :
587 2 : if (relaxstr == 1) then
588 :
589 : ! Compute the stresses induced by the electric field
590 2 : sigelfd(:) = zero
591 2 : istrain = 0
592 6 : do ipert = 1, 2
593 4 : jpert = natom + 2 + ipert
594 18 : do idir = 1, 3
595 12 : istrain = istrain + 1
596 48 : do jdir = 1, 3
597 36 : index = idir +3*((jpert - 1) + mpert*((jdir - 1) + 3*(natom + 1)))
598 48 : sigelfd(istrain) = sigelfd(istrain) + lambda(jdir)*blkval(1,index)
599 : end do
600 16 : sigelfd(istrain) = sigelfd(istrain)/ucvol
601 : end do
602 : end do
603 :
604 : ! Compute the remaining stresses and write them out
605 14 : diffsig(:) = strten(:) - sigelfd(:)
606 2 : sigmax = zero
607 14 : do istrain = 1, 6
608 14 : if (abs(diffsig(istrain)) > sigmax) sigmax = abs(diffsig(istrain))
609 : end do
610 2 : if (iwrite) then
611 2 : write(iout,*)
612 2 : write(iout,*)'Difference between the Hellmann-Feynman stresses'
613 2 : write(iout,*)'and the stresses induced by the electric field'
614 2 : write(iout,*)'(cartesian coordinates, hartree/bohr^3)'
615 2 : write(iout,'(2x,a,f16.9,5x,a,f16.9)')'diffsig(1) = ',diffsig(1),'diffsig(4) = ',diffsig(4)
616 2 : write(iout,'(2x,a,f16.9,5x,a,f16.9)')'diffsig(2) = ',diffsig(2),'diffsig(5) = ',diffsig(5)
617 2 : write(iout,'(2x,a,f16.9,5x,a,f16.9)')'diffsig(3) = ',diffsig(3),'diffsig(6) = ',diffsig(6)
618 2 : write(iout,'(a,3x,es16.9)')' sigmax = ',sigmax
619 2 : write(iout,*)
620 2 : write(iout,*)'Induced strain (delta_eta):'
621 2 : write(iout,'(2x,a,f16.9,5x,a,f16.9)')'delta_eta(1) = ',delta_eta(1),'delta_eta(4) = ',delta_eta(4)
622 2 : write(iout,'(2x,a,f16.9,5x,a,f16.9)')'delta_eta(2) = ',delta_eta(2),'delta_eta(5) = ',delta_eta(5)
623 2 : write(iout,'(2x,a,f16.9,5x,a,f16.9)')'delta_eta(3) = ',delta_eta(3),'delta_eta(6) = ',delta_eta(6)
624 2 : write(iout,*)
625 2 : write(iout,*)'New lattice constants (acell_new):'
626 2 : write(iout,*)' acell'
627 2 : write(iout,'(3(2x,d22.14))')(acell_new(idir),idir = 1, 3)
628 2 : write(iout,*)
629 2 : write(iout,*)'New primitive vectors (rprim_new):'
630 2 : write(iout,*)' rprim'
631 2 : write(iout,'(3(2x,d22.14))')(rprim(idir,1),idir = 1, 3)
632 2 : write(iout,'(3(2x,d22.14))')(rprim(idir,2),idir = 1, 3)
633 2 : write(iout,'(3(2x,d22.14))')(rprim(idir,3),idir = 1, 3)
634 : end if
635 : end if ! relaxstr /= 0
636 :
637 : end if ! (relaxat /= 0).or.(relaxstr /= 0)
638 :
639 3 : ABI_FREE(cfac)
640 3 : ABI_FREE(fdiff)
641 3 : ABI_FREE(felfd)
642 3 : ABI_FREE(delta)
643 3 : ABI_FREE(fcart)
644 3 : ABI_FREE(fcmat)
645 3 : ABI_FREE(ifcmat)
646 3 : ABI_FREE(ipvt)
647 3 : ABI_FREE(rfpert)
648 3 : ABI_FREE(vec)
649 3 : ABI_FREE(zgwork)
650 3 : ABI_FREE(irelaxat)
651 :
652 3 : end subroutine relaxpol
653 : !!***
654 :
655 : end module m_relaxpol
656 : !!***
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