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introduce cutoff step. make lbfgs stable

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This commit is contained in:
alxvov
2019-07-04 15:31:18 +00:00
parent 95cf85f1b9
commit e85bdd17d3
2 changed files with 92 additions and 27 deletions
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107
src/SPIN/min_spin_oso_lbfgs.cpp
View File

@ -38,7 +38,6 @@
#include "modify.h"
#include "math_special.h"
#include "math_const.h"
#include "universe.h"
using namespace LAMMPS_NS;
@ -96,6 +95,8 @@ void MinSpinOSO_LBFGS::init()
alpha_damp = 1.0;
discrete_factor = 10.0;
num_mem = 3;
local_iter = 0;
maxepsrot = MY_2PI / (200.0);
Min::init();
@ -180,6 +181,7 @@ int MinSpinOSO_LBFGS::iterate(int maxiter)
if (nlocal_max < nlocal) {
nlocal_max = nlocal;
local_iter = 0;
memory->grow(g_old,3*nlocal_max,"min/spin/oso/lbfgs:g_old");
memory->grow(g_cur,3*nlocal_max,"min/spin/oso/lbfgs:g_cur");
memory->grow(p_s,3*nlocal_max,"min/spin/oso/lbfgs:p_s");
@ -198,26 +200,26 @@ int MinSpinOSO_LBFGS::iterate(int maxiter)
// optimize timestep accross processes / replicas
// need a force calculation for timestep optimization
if (iter == 0){
energy_force(0);
dts = evaluate_dt();
}
else dts = 1.0;
if (local_iter == 0) energy_force(0);
// to be checked
// if gneb calc., nreplica > 1
// then calculate gradients of intermediate replicas
calc_gradient(dts);
if (nreplica > 1) {
if(ireplica != 0 && ireplica != nreplica-1)
calc_gradient(1.0);
} else calc_gradient(1.0);
calc_search_direction(iter);
// to be checked
// if gneb calc., nreplica > 0
// if gneb calc., nreplica > 1
// then advance spins only if intermediate replica
// otherwise (simple minimization), advance spins
if (nreplica > 0) {
if (nreplica > 1) {
if(ireplica != 0 && ireplica != nreplica-1)
advance_spins();
} else advance_spins();
eprevious = ecurrent;
ecurrent = energy_force(0);
neval++;
@ -307,7 +309,7 @@ double MinSpinOSO_LBFGS::evaluate_dt()
// define max timestep by dividing by the
// inverse of max frequency by discrete_factor
// std::cout << fmaxsqall << "\n";
dtmax = MY_2PI/(discrete_factor*sqrt(fmaxsqall));
return dtmax;
@ -365,20 +367,31 @@ void MinSpinOSO_LBFGS::calc_search_direction(int iter)
double yr_global = 0.0;
double beta_global = 0.0;
int m_index = iter % num_mem; // memory index
int m_index = local_iter % num_mem; // memory index
int c_ind = 0;
double *q;
double *alpha;
double factor;
double scaling;
if (nreplica > 1) {
if (ireplica == 0 || ireplica == nreplica - 1) {
factor = 0.0;
}
else factor = 1.0;
}else{
factor = 1.0;
}
q = (double *) calloc(3*nlocal, sizeof(double));
alpha = (double *) calloc(num_mem, sizeof(double));
// for some reason on a second iteration g_old = 0
// so we make two iterations as steepest descent
if (iter == 0){ // steepest descent direction
if (local_iter == 0){ // steepest descent direction
scaling = maximum_rotation(g_cur);
for (int i = 0; i < 3 * nlocal; i++) {
p_s[i] = -g_cur[i];
p_s[i] = - g_cur[i] * factor * scaling;
g_old[i] = g_cur[i];
ds[m_index][i] = 0.0;
dy[m_index][i] = 0.0;
@ -392,7 +405,9 @@ void MinSpinOSO_LBFGS::calc_search_direction(int iter)
dyds += ds[m_index][i] * dy[m_index][i];
}
MPI_Allreduce(&dyds, &dyds_global, 1, MPI_DOUBLE, MPI_SUM, world);
if (update->multireplica == 1) {
dyds_global *= factor;
dyds = dyds_global;
MPI_Allreduce(&dyds, &dyds_global, 1,MPI_DOUBLE,MPI_SUM,universe->uworld);
}
@ -400,6 +415,17 @@ void MinSpinOSO_LBFGS::calc_search_direction(int iter)
if (fabs(dyds_global) > 1.0e-60) rho[m_index] = 1.0 / dyds_global;
else rho[m_index] = 1.0e60;
if (rho[m_index] < 0.0){
local_iter = 0;
for (int k = 0; k < num_mem; k++){
for (int i = 0; i < nlocal; i ++){
ds[k][i] = 0.0;
dy[k][i] = 0.0;
}
}
return calc_search_direction(0);
}
// set the q vector
for (int i = 0; i < 3 * nlocal; i++) {
@ -420,6 +446,7 @@ void MinSpinOSO_LBFGS::calc_search_direction(int iter)
}
MPI_Allreduce(&sq, &sq_global, 1, MPI_DOUBLE, MPI_SUM, world);
if (update->multireplica == 1) {
sq_global *= factor;
sq = sq_global;
MPI_Allreduce(&sq,&sq_global,1,MPI_DOUBLE,MPI_SUM,universe->uworld);
}
@ -442,19 +469,22 @@ void MinSpinOSO_LBFGS::calc_search_direction(int iter)
}
MPI_Allreduce(&yy, &yy_global, 1, MPI_DOUBLE, MPI_SUM, world);
if (update->multireplica == 1) {
yy_global *= factor;
yy = yy_global;
MPI_Allreduce(&yy,&yy_global,1,MPI_DOUBLE,MPI_SUM,universe->uworld);
}
// calculate now search direction
if (fabs(yy_global) > 1.0e-60) {
double devis = rho[m_index] * yy_global;
if (fabs(devis) > 1.0e-60) {
for (int i = 0; i < 3 * nlocal; i++) {
p_s[i] = q[i] / (rho[m_index] * yy_global);
p_s[i] = factor * q[i] / devis;
}
}else{
for (int i = 0; i < 3 * nlocal; i++) {
p_s[i] = q[i] * 1.0e60;
p_s[i] = factor * q[i] * 1.0e60;
}
}
@ -472,6 +502,7 @@ void MinSpinOSO_LBFGS::calc_search_direction(int iter)
MPI_Allreduce(&yr, &yr_global, 1, MPI_DOUBLE, MPI_SUM, world);
if (update->multireplica == 1) {
yr_global *= factor;
yr = yr_global;
MPI_Allreduce(&yr,&yr_global,1,MPI_DOUBLE,MPI_SUM,universe->uworld);
}
@ -481,12 +512,14 @@ void MinSpinOSO_LBFGS::calc_search_direction(int iter)
p_s[i] += ds[c_ind][i] * (alpha[c_ind] - beta);
}
}
scaling = maximum_rotation(p_s);
for (int i = 0; i < 3 * nlocal; i++) {
p_s[i] = -1.0 * p_s[i];
p_s[i] = - factor * p_s[i] * scaling;
g_old[i] = g_cur[i];
}
}
local_iter++;
free(q);
free(alpha);
@ -631,3 +664,33 @@ void MinSpinOSO_LBFGS::vm3(const double *m, const double *v, double *out)
}
}
}
double MinSpinOSO_LBFGS::maximum_rotation(double *p)
{
double norm, norm_global, scaling, alpha;
int nlocal = atom->nlocal;
int ntotal = 0;
norm = 0.0;
for (int i = 0; i < 3 * nlocal; i++) norm += p[i] * p[i];
MPI_Allreduce(&norm,&norm_global,1,MPI_DOUBLE,MPI_SUM,world);
if (update->multireplica == 1) {
norm = norm_global;
MPI_Allreduce(&norm,&norm_global,1,MPI_DOUBLE,MPI_SUM,universe->uworld);
}
MPI_Allreduce(&nlocal,&ntotal,1,MPI_INT,MPI_SUM,world);
if (update->multireplica == 1) {
nlocal = ntotal;
MPI_Allreduce(&nlocal,&ntotal,1,MPI_INT,MPI_SUM,universe->uworld);
}
scaling = (maxepsrot * sqrt((double) ntotal / norm_global));
if (scaling < 1.0) alpha = scaling;
else alpha = 1.0;
return alpha;
}

12
src/SPIN/min_spin_oso_lbfgs.h
View File

@ -38,8 +38,8 @@ public:
void advance_spins();
double fmnorm_sqr();
void calc_gradient(double);
void calc_search_direction(int);
void calc_search_direction(int);
double maximum_rotation(double *);
private:
@ -64,11 +64,13 @@ private:
double **ds; // change in rotation matrix between two iterations, da
double **dy; // change in gradients between two iterations, dg
double *rho; // estimation of curvature
int num_mem; // number of stored steps
int num_mem; // number of stored steps
int local_iter; // number of times we call search_direction
double maxepsrot;
void vm3(const double *m, const double *v, double *out);
void rodrigues_rotation(const double *upp_tr, double *out);
void vm3(const double *, const double *, double *);
void rodrigues_rotation(const double *, double *);
bigint last_negative;
};