void QuasiNewton::optimize_vertex_positions( PatchData& pd, MsqError& err )
{
TerminationCriterion& term = *get_inner_termination_criterion();
OFEvaluator& func = get_objective_function_evaluator();
const double sigma = 1e-4;
const double beta0 = 0.25;
const double beta1 = 0.80;
const double tol1 = 1e-8;
const double epsilon = 1e-10;
double norm_r; //, norm_g;
double alpha, beta;
double obj, objn;
size_t i;
// Initialize stuff
const size_t nn = pd.num_free_vertices();
double a[QNVEC], b[QNVEC], r[QNVEC];
for (i = 0; i < QNVEC; ++i)
r[i] = 0;
for (i = 0; i <= QNVEC; ++i) {
v[i].clear();
v[i].resize( nn, Vector3D(0.0) );
w[i].clear();
w[i].resize( nn, Vector3D(0.0) );
}
d.resize( nn );
mHess.resize( nn ); //hMesh(mesh);
bool valid = func.update( pd, obj, v[QNVEC], mHess, err ); MSQ_ERRRTN(err);
if (!valid) {
MSQ_SETERR(err)("Initial objective function is not valid", MsqError::INVALID_MESH);
return;
}
while (!term.terminate()) {
pd.recreate_vertices_memento( mMemento, err ); MSQ_ERRRTN(err);
pd.get_free_vertex_coordinates( w[QNVEC] );
x = v[QNVEC];
for (i = QNVEC; i--; ) {
a[i] = r[i] * inner( &(w[i][0]), arrptr(x), nn );
plus_eq_scaled( arrptr(x), -a[i], &v[i][0], nn );
}
solve( arrptr(d), arrptr(x) );
for (i = QNVEC; i--; ) {
b[i] = r[i] * inner( &(v[i][0]), arrptr(d), nn );
plus_eq_scaled( arrptr(d), a[i]-b[i], &(w[i][0]), nn );
}
alpha = -inner( &(v[QNVEC][0]), arrptr(d), nn ); /* direction is negated */
if (alpha > 0.0) {
MSQ_SETERR(err)("No descent.", MsqError::INVALID_MESH);
return;
}
alpha *= sigma;
beta = 1.0;
pd.move_free_vertices_constrained( arrptr(d), nn, -beta, err ); MSQ_ERRRTN(err);
valid = func.evaluate( pd, objn, v[QNVEC], err );
if (err.error_code() == err.BARRIER_VIOLATED)
err.clear(); // barrier violated does not represent an actual error here
MSQ_ERRRTN(err);
if (!valid ||
(obj - objn < -alpha*beta - epsilon &&
length( &(v[QNVEC][0]), nn ) >= tol1)) {
if (!valid) // function not defined at trial point
beta *= beta0;
else // unacceptable iterate
beta *= beta1;
for (;;) {
if (beta < tol1) {
pd.set_to_vertices_memento( mMemento, err ); MSQ_ERRRTN(err);
MSQ_SETERR(err)("Newton step not good", MsqError::INTERNAL_ERROR);
return;
}
pd.set_free_vertices_constrained( mMemento, arrptr(d), nn, -beta, err ); MSQ_ERRRTN(err);
valid = func.evaluate( pd, objn, err );
if (err.error_code() == err.BARRIER_VIOLATED)
err.clear(); // barrier violated does not represent an actual error here
MSQ_ERRRTN(err);
if (!valid) // function undefined at trial point
beta *= beta0;
else if (obj - objn < -alpha*beta - epsilon) // unacceptlable iterate
beta *= beta1;
else
break;
}
}
for (i = 0; i < QNVEC-1; ++i) {
r[i] = r[i+1];
w[i].swap( w[i+1] );
v[i].swap( v[i+1] );
}
w[QNVEC-1].swap( w[0] );
v[QNVEC-1].swap( v[0] );
func.update( pd, obj, v[QNVEC], mHess, err ); MSQ_ERRRTN(err);
norm_r = length_squared( &(v[QNVEC][0]), nn );
//norm_g = sqrt(norm_r);
// checks stopping criterion
term.accumulate_patch( pd, err ); MSQ_ERRRTN(err);
term.accumulate_inner( pd, objn, &v[QNVEC][0], err ); MSQ_ERRRTN(err);
}
}
void TrustRegion::optimize_vertex_positions( PatchData& pd, MsqError& err )
{
TerminationCriterion& term = *get_inner_termination_criterion();
OFEvaluator& func = get_objective_function_evaluator();
const double cg_tol = 1e-2;
const double eta_1 = 0.01;
const double eta_2 = 0.90;
const double tr_incr = 10;
const double tr_decr_def = 0.25;
const double tr_decr_undef = 0.25;
const double tr_num_tol = 1e-6;
const int max_cg_iter = 10000;
double radius = 1000; /* delta*delta */
const int nn = pd.num_free_vertices();
wVect.resize(nn); Vector3D* w = arrptr(wVect);
zVect.resize(nn); Vector3D* z = arrptr(zVect);
dVect.resize(nn); Vector3D* d = arrptr(dVect);
pVect.resize(nn); Vector3D* p = arrptr(pVect);
rVect.resize(nn); Vector3D* r = arrptr(rVect);
double norm_r, norm_g;
double alpha, beta, kappa;
double rz, rzm1;
double dMp, norm_d, norm_dp1, norm_p;
double obj, objn;
int cg_iter;
bool valid;
mHess.initialize( pd, err ); //hMesh(mesh);
valid = func.update( pd, obj, mGrad, mHess, err ); MSQ_ERRRTN(err);
if (!valid) {
MSQ_SETERR(err)("Initial objective function is not valid", MsqError::INVALID_MESH);
return;
}
compute_preconditioner( err ); MSQ_ERRRTN(err);
pd.recreate_vertices_memento( mMemento, err ); MSQ_ERRRTN(err);
while (!term.terminate() && (radius > 1e-20)) {
norm_r = length_squared(arrptr(mGrad), nn);
norm_g = sqrt(norm_r);
memset(d, 0, 3*sizeof(double)*nn);
memcpy(r, arrptr(mGrad), nn*sizeof(Vector3D)); //memcpy(r, mesh->g, 3*sizeof(double)*nn);
norm_g *= cg_tol;
apply_preconditioner( z, r, err); MSQ_ERRRTN(err); //prec->apply(z, r, prec, mesh);
negate(p, z, nn);
rz = inner(r, z, nn);
dMp = 0;
norm_p = rz;
norm_d = 0;
cg_iter = 0;
while ((sqrt(norm_r) > norm_g) &&
#ifdef DO_STEEP_DESC
(norm_d > tr_num_tol) &&
#endif
(cg_iter < max_cg_iter))
{
++cg_iter;
memset(w, 0, 3*sizeof(double)*nn);
//matmul(w, mHess, p); //matmul(w, mesh, p);
mHess.product( w, p );
kappa = inner(p, w, nn);
if (kappa <= 0.0) {
alpha = (sqrt(dMp*dMp+norm_p*(radius-norm_d))-dMp)/norm_p;
plus_eq_scaled( d, alpha, p, nn );
break;
}
alpha = rz / kappa;
norm_dp1 = norm_d + 2.0*alpha*dMp + alpha*alpha*norm_p;
if (norm_dp1 >= radius) {
alpha = (sqrt(dMp*dMp+norm_p*(radius-norm_d))-dMp)/norm_p;
plus_eq_scaled( d, alpha, p, nn );
break;
}
plus_eq_scaled( d, alpha, p, nn );
plus_eq_scaled( r, alpha, w, nn );
norm_r = length_squared(r, nn);
apply_preconditioner( z, r, err); MSQ_ERRRTN(err); //prec->apply(z, r, prec, mesh);
rzm1 = rz;
rz = inner(r, z, nn);
beta = rz / rzm1;
times_eq_minus( p, beta, z, nn );
dMp = beta*(dMp + alpha*norm_p);
norm_p = rz + beta*beta*norm_p;
norm_d = norm_dp1;
}
#ifdef DO_STEEP_DESC
if (norm_d <= tr_num_tol) {
norm_g = length(arrptr(mGrad), nn);
double ll = 1.0;
if (norm_g < tr_num_tol)
break;
if (norm_g > radius)
ll = radius / nurm_g;
for (int i = 0; i < nn; ++i)
d[i] = ll * mGrad[i];
}
#endif
alpha = inner( arrptr(mGrad), d, nn ); // inner(mesh->g, d, nn);
memset(p, 0, 3*sizeof(double)*nn);
//matmul(p, mHess, d); //matmul(p, mesh, d);
mHess.product( p, d );
beta = 0.5*inner(p, d, nn);
kappa = alpha + beta;
/* Put the new point into the locations */
pd.move_free_vertices_constrained( d, nn, 1.0, err ); MSQ_ERRRTN(err);
valid = func.evaluate( pd, objn, err ); MSQ_ERRRTN(err);
if (!valid) {
/* Function not defined at trial point */
radius *= tr_decr_undef;
pd.set_to_vertices_memento( mMemento, err ); MSQ_ERRRTN(err);
continue;
}
if ((fabs(kappa) <= tr_num_tol) && (fabs(objn - obj) <= tr_num_tol)) {
kappa = 1;
}
else {
kappa = (objn - obj) / kappa;
}
if (kappa < eta_1) {
/* Iterate is unacceptable */
radius *= tr_decr_def;
pd.set_to_vertices_memento( mMemento, err ); MSQ_ERRRTN(err);
continue;
}
/* Iterate is acceptable */
if (kappa >= eta_2) {
/* Iterate is a very good step, increase radius */
radius *= tr_incr;
if (radius > 1e20) {
radius = 1e20;
}
}
func.update( pd, obj, mGrad, mHess, err );
compute_preconditioner( err ); MSQ_ERRRTN(err);
pd.recreate_vertices_memento( mMemento, err ); MSQ_ERRRTN(err);
// checks stopping criterion
term.accumulate_patch( pd, err ); MSQ_ERRRTN(err);
term.accumulate_inner( pd, objn, arrptr(mGrad), err ); MSQ_ERRRTN(err);
}
}