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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@1751 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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sjplimp
2008-04-15 21:43:15 +00:00
parent 23b15a6bed
commit 8a08b7f3da
4 changed files with 26 additions and 23 deletions
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32
src/min_cg.cpp
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@ -294,8 +294,7 @@ int MinCG::iterate(int n)
// line minimization along direction h from current atom->x
eprevious = ecurrent;
fail = (this->*linemin)(ndof,atom->x[0],h,ecurrent,dmin,dmax,
alpha_final,neval);
fail = (this->*linemin)(ndof,atom->x[0],h,ecurrent,dmax,alpha_final,neval);
if (fail) return FAIL;
// function evaluation criterion
@ -479,7 +478,7 @@ void MinCG::force_clear()
x = ptr to atom->x[0] as vector
dir = search direction as vector
eng = current energy at initial x
min/max dist = min/max distance to move any atom coord
maxdist = max distance to move any atom coord
output: return 0 if successful move, non-zero alpha alpha
return 1 if failed, alpha = 0.0
alpha = distance moved along dir to set x to minimun eng config
@ -502,45 +501,48 @@ void MinCG::force_clear()
------------------------------------------------------------------------- */
int MinCG::linemin_backtrack(int n, double *x, double *dir, double eng,
double mindist, double maxdist,
double &alpha, int &nfunc)
double maxdist, double &alpha, int &nfunc)
{
int i,ilist,m;
double fdotdirme,fdotdirall,fme,fmax,eoriginal,alphamax;
int i,m;
// stopping criterion, must be scaled by normflag
double *f = atom->f[0];
fdotdirme = 0.0;
double fdotdirme = 0.0;
for (i = 0; i < n; i++) fdotdirme += f[i]*dir[i];
double fdotdirall;
MPI_Allreduce(&fdotdirme,&fdotdirall,1,MPI_DOUBLE,MPI_SUM,world);
if (output->thermo->normflag) fdotdirall /= atom->natoms;
// alphamax = step that moves some atom coord by maxdist
fme = 0.0;
double fme = 0.0;
for (i = 0; i < n; i++) fme = MAX(fme,fabs(dir[i]));
double fmax;
MPI_Allreduce(&fme,&fmax,1,MPI_DOUBLE,MPI_MAX,world);
if (fmax == 0.0) return 1;
alphamax = maxdist/fmax;
double alphamax = maxdist/fmax;
// reduce alpha by factor of ALPHA_REDUCE until energy decrease is sufficient
// reduce alpha by ALPHA_REDUCE until energy decrease is sufficient
eoriginal = eng;
double eoriginal = eng;
alpha = alphamax;
double alpha_previous = 0.0;
double delta;
while (1) {
for (i = 0; i < n; i++) x[i] += alpha*dir[i];
delta = alpha - alpha_previous;
for (i = 0; i < n; i++) x[i] += delta*dir[i];
eng_force(&n,&x,&dir,&eng);
nfunc++;
if (eng <= eoriginal - BACKTRACK_SLOPE*alpha*fdotdirall) return 0;
for (i = 0; i < n; i++) x[i] -= alpha*dir[i];
alpha_previous = alpha;
alpha *= ALPHA_REDUCE;
if (alpha == 0.0) {
for (i = 0; i < n; i++) x[i] -= alpha_previous*dir[i];
eng_force(&n,&x,&dir,&eng);
return 1;
}