Files
lammps/src/MLIAP/mliap_model_nn.cpp
Axel Kohlmeyer b9028a07bf bugfix
2021-03-11 22:09:50 -05:00

416 lines
12 KiB
C++

/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
https://lammps.sandia.gov/, Sandia National Laboratories
Steve Plimpton, sjplimp@sandia.gov
Copyright (2003) Sandia Corporation. Under the terms of Contract
DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
certain rights in this software. This software is distributed under
the GNU General Public License.
See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */
/* ----------------------------------------------------------------------
Contributing author: Pedro Antonio Santos Flórez (UNLV)
------------------------------------------------------------------------- */
#include "mliap_model_nn.h"
#include "pair_mliap.h"
#include "mliap_data.h"
#include "error.h"
#include "comm.h"
#include "memory.h"
#include "tokenizer.h"
#include <cmath>
using namespace LAMMPS_NS;
#define MAXLINE 1024
/* ---------------------------------------------------------------------- */
MLIAPModelNN::MLIAPModelNN(LAMMPS* lmp, char* coefffilename) :
MLIAPModel(lmp, coefffilename)
{
coeffelem = nullptr;
nnodes = nullptr;
activation = nullptr;
scale = nullptr;
if (coefffilename) read_coeffs(coefffilename);
}
/* ---------------------------------------------------------------------- */
MLIAPModelNN::~MLIAPModelNN()
{
memory->destroy(coeffelem);
memory->destroy(nnodes);
memory->destroy(activation);
memory->destroy(scale);
}
/* ----------------------------------------------------------------------
get number of parameters
---------------------------------------------------------------------- */
int MLIAPModelNN::get_nparams()
{
if (nparams == 0)
if (ndescriptors == 0) error->all(FLERR,"ndescriptors not defined");
return nparams;
}
void MLIAPModelNN::read_coeffs(char *coefffilename)
{
// open coefficient file on proc 0
FILE *fpcoeff;
if (comm->me == 0) {
fpcoeff = utils::open_potential(coefffilename,lmp,nullptr);
if (fpcoeff == nullptr)
error->one(FLERR,fmt::format("Cannot open MLIAPModel coeff file {}: {}",
coefffilename,utils::getsyserror()));
}
char line[MAXLINE], *ptr, *tstr;
int eof = 0;
int n;
int nwords = 0;
while (nwords == 0) {
if (comm->me == 0) {
ptr = fgets(line,MAXLINE,fpcoeff);
if (ptr == nullptr) {
eof = 1;
fclose(fpcoeff);
} else n = strlen(line) + 1;
}
MPI_Bcast(&eof,1,MPI_INT,0,world);
if (eof) break;
MPI_Bcast(&n,1,MPI_INT,0,world);
MPI_Bcast(line,n,MPI_CHAR,0,world);
// strip comment, skip line if blank
if ((ptr = strchr(line,'#'))) *ptr = '\0';
nwords = utils::count_words(line);
}
if (nwords != 2)
error->all(FLERR,"Incorrect format in MLIAPModel coefficient file");
// words = ptrs to all words in line
// strip single and double quotes from words
try {
ValueTokenizer coeffs(line);
nelements = coeffs.next_int();
nparams = coeffs.next_int();
} catch (TokenizerException &e) {
error->all(FLERR,fmt::format("Incorrect format in MLIAPModel coefficient "
"file: {}",e.what()));
}
// set up coeff lists
memory->create(coeffelem,nelements,nparams,"mliap_snap_model:coeffelem");
int stats = 0;
int ielem = 0;
int l = 0;
while (1) {
if (comm->me == 0) {
ptr = fgets(line,MAXLINE,fpcoeff);
if (ptr == nullptr) {
eof = 1;
fclose(fpcoeff);
} else n = strlen(line) + 1;
}
MPI_Bcast(&eof,1,MPI_INT,0,world);
if (eof) break;
MPI_Bcast(&n,1,MPI_INT,0,world);
MPI_Bcast(line,n,MPI_CHAR,0,world);
// strip comment, skip line if blank
if ((ptr = strchr(line,'#'))) *ptr = '\0';
nwords = utils::trim_and_count_words(line);
if (nwords == 0) continue;
if (stats == 0) { // Header NET
tstr = strtok(line,"' \t\n\r\f");
if (strncmp(tstr, "NET", 3) != 0) error->all(FLERR,"Incorrect format in MLIAPModel coefficient file");
ndescriptors = atoi(strtok(nullptr,"' \t\n\r\f"));
nlayers = atoi(strtok(nullptr,"' \t\n\r\f"));
memory->create(activation,nlayers,"mliap_model:activation");
memory->create(nnodes,nlayers,"mliap_model:nnodes");
memory->create(scale,nelements,2,ndescriptors,"mliap_model:scale");
for (int ilayer = 0; ilayer < nlayers; ilayer++) {
tstr = strtok(NULL,"' \t\n\r\f");
nnodes[ilayer] = atoi(strtok(NULL,"' \t\n\r\f"));
if (strncmp(tstr, "linear", 6) == 0) activation[ilayer] = 0;
else if (strncmp(tstr, "sigmoid", 7) == 0) activation[ilayer] = 1;
else if (strncmp(tstr, "tanh", 4) == 0) activation[ilayer] = 2;
else if (strncmp(tstr, "relu", 4) == 0) activation[ilayer] = 3;
else activation[ilayer] = 4;
}
stats = 1;
} else if (stats == 1) {
scale[ielem][0][l] = atof(strtok(line,"' \t\n\r\f"));
for (int icoeff = 1; icoeff < nwords; icoeff++) {
scale[ielem][0][l+icoeff] = atof(strtok(nullptr,"' \t\n\r\f"));
}
l += nwords;
if (l == ndescriptors) {
stats = 2;
l = 0;
}
} else if (stats == 2) {
scale[ielem][1][l] = atof(strtok(line,"' \t\n\r\f"));
for (int icoeff = 1; icoeff < nwords; icoeff++) {
scale[ielem][1][l+icoeff] = atof(strtok(nullptr,"' \t\n\r\f"));
}
l += nwords;
if (l == ndescriptors) {
stats = 3;
l = 0;
}
// set up coeff lists
} else if (stats == 3) {
if (nwords > 30) error->all(FLERR,"Incorrect format in MLIAPModel coefficient file");
coeffelem[ielem][l] = atof(strtok(line,"' \t\n\r\f"));
for (int icoeff = 1; icoeff < nwords; icoeff++) {
coeffelem[ielem][l+icoeff] = atof(strtok(nullptr,"' \t\n\r\f"));
}
l += nwords;
if (l == nparams) {
stats = 1;
l = 0;
ielem++;
}
}
}
}
/* ----------------------------------------------------------------------
Calculate model gradients w.r.t descriptors
for each atom beta_i = dE(B_i)/dB_i
---------------------------------------------------------------------- */
void MLIAPModelNN::compute_gradients(MLIAPData* data)
{
data->energy = 0.0;
for (int ii = 0; ii < data->nlistatoms; ii++) {
const int ielem = data->ielems[ii];
const int nl = nlayers;
double* coeffi = coeffelem[ielem];
double** scalei = scale[ielem];
double **nodes, **dnodes, **bnodes;
nodes = new double*[nl];
dnodes = new double*[nl];
bnodes = new double*[nl];
for (int l=0; l<nl; ++l) {
nodes[l] = new double[nnodes[l]];
dnodes[l] = new double[nnodes[l]];
bnodes[l] = new double[nnodes[l]];
}
// forwardprop
// input - hidden1
for (int n=0; n < nnodes[0]; n++) {
nodes[0][n] = 0;
for (int icoeff = 0; icoeff < data->ndescriptors; icoeff++) {
nodes[0][n] += coeffi[n*((data->ndescriptors)+1)+icoeff+1] *
(data->descriptors[ii][icoeff] - scalei[0][icoeff]) /
scalei[1][icoeff];
}
if (activation[0] == 1) {
nodes[0][n] = sigm(nodes[0][n] +
coeffi[n*((data->ndescriptors)+1)],
dnodes[0][n]);
}
else if (activation[0] == 2) {
nodes[0][n] = tanh(nodes[0][n] +
coeffi[n*((data->ndescriptors)+1)],
dnodes[0][n]);
}
else if (activation[0] == 3) {
nodes[0][n] = relu(nodes[0][n] +
coeffi[n*((data->ndescriptors)+1)],
dnodes[0][n]);
}
else {
nodes[0][n] += coeffi[n*((data->ndescriptors)+1)];
dnodes[0][n] = 1;
}
}
// hidden~output
int k = 0;
if (nl > 1) {
k += ((data->ndescriptors)+1)*nnodes[0];
for (int l=1; l < nl; l++) {
for (int n=0; n < nnodes[l]; n++) {
nodes[l][n] = 0;
for (int j=0; j < nnodes[l-1]; j++) {
nodes[l][n] += coeffi[k+n*(nnodes[l-1]+1)+j+1] *
nodes[l-1][j];
}
if (activation[l] == 1) {
nodes[l][n] = sigm(nodes[l][n] +
coeffi[k+n*(nnodes[l-1]+1)],
dnodes[l][n]);
}
else if (activation[l] == 2) {
nodes[l][n] = tanh(nodes[l][n] +
coeffi[k+n*(nnodes[l-1]+1)],
dnodes[l][n]);
}
else if (activation[l] == 3) {
nodes[l][n] = relu(nodes[l][n] +
coeffi[k+n*(nnodes[l-1]+1)],
dnodes[l][n]);
}
else {
nodes[l][n] += coeffi[k+n*(nnodes[l-1]+1)];
dnodes[l][n] = 1;
}
}
k += (nnodes[l-1]+1)*nnodes[l];
}
}
// backwardprop
// output layer dnode initialized to 1.
for (int n=0; n<nnodes[nl-1]; n++) {
if (activation[nl-1] == 0) {
bnodes[nl-1][n] = 1;
}
else {
bnodes[nl-1][n] = dnodes[nl-1][n];
}
}
if (nl > 1) {
for (int l=nl-1; l>0; l--) {
k -= (nnodes[l-1]+1)*nnodes[l];
for (int n=0; n<nnodes[l-1]; n++) {
bnodes[l-1][n] = 0;
for (int j=0; j<nnodes[l]; j++) {
bnodes[l-1][n] += coeffi[k+j*(nnodes[l-1]+1)+n+1] *
bnodes[l][j];
}
if (activation[l-1] >= 1) {
bnodes[l-1][n] *= dnodes[l-1][n];
}
}
}
}
for (int icoeff = 0; icoeff < data->ndescriptors; icoeff++) {
data->betas[ii][icoeff] = 0;
for (int j=0; j<nnodes[0]; j++) {
data->betas[ii][icoeff] +=
coeffi[j*((data->ndescriptors)+1)+icoeff+1] *
bnodes[0][j];
}
data->betas[ii][icoeff] = data->betas[ii][icoeff]/scalei[1][icoeff];
}
if (data->eflag) {
// energy of atom I (E_i)
double etmp = nodes[nl-1][0];
data->energy += etmp;
data->eatoms[ii] = etmp;
}
// Deleting the variables
for (int n=0; n<nl; n++) {
delete nodes[n];
delete dnodes[n];
delete bnodes[n];
}
delete[] nodes;
delete[] dnodes;
delete[] bnodes;
}
}
/* ----------------------------------------------------------------------
Calculate model double gradients w.r.t descriptors and parameters
for each atom energy gamma_lk = d2E(B)/dB_k/dsigma_l,
where sigma_l is a parameter, B_k a descriptor,
and atom subscript i is omitted
gamma is in CSR format:
nnz = number of non-zero values
gamma_row_index[inz] = l indices, 0 <= l < nparams
gamma_col_indexiinz] = k indices, 0 <= k < ndescriptors
gamma[i][inz] = non-zero values, 0 <= inz < nnz
egradient is derivative of energy w.r.t. parameters
---------------------------------------------------------------------- */
void MLIAPModelNN::compute_gradgrads(class MLIAPData * /*data*/)
{
error->all(FLERR,"compute_gradgrads not implemented");
}
/* ----------------------------------------------------------------------
calculate gradients of forces w.r.t. parameters
egradient is derivative of energy w.r.t. parameters
---------------------------------------------------------------------- */
void MLIAPModelNN::compute_force_gradients(class MLIAPData * /*data*/)
{
error->all(FLERR,"compute_force_gradients not implemented");
}
/* ----------------------------------------------------------------------
count the number of non-zero entries in gamma matrix
---------------------------------------------------------------------- */
int MLIAPModelNN::get_gamma_nnz(class MLIAPData * /*data*/)
{
// todo: get_gamma_nnz
return 0;
}
double MLIAPModelNN::memory_usage()
{
double bytes = 0;
bytes += (double)nelements*nparams*sizeof(double); // coeffelem
bytes += (double)nelements*2*ndescriptors*sizeof(double); // scale
bytes += (int)nlayers*sizeof(int); // nnodes
bytes += (int)nlayers*sizeof(int); // activation
return bytes;
}