+ apply suggested improvements to the new freegcs solvers

+ detect diverging solutions and NaN


git-svn-id: https://free-cad.svn.sourceforge.net/svnroot/free-cad/trunk@5114 e8eeb9e2-ec13-0410-a4a9-efa5cf37419d
This commit is contained in:
logari81 2011-11-10 23:39:08 +00:00
parent 48d52b6a8b
commit 5686310a0f

View File

@ -613,13 +613,10 @@ int System::solve_LM(SubSystem* subsys)
if (xsize == 0)
return Success;
int itmax = MaxIterations*xsize;
Eigen::VectorXd e(csize), e_new(csize); // vector of all function errors (every constraint is one function)
Eigen::MatrixXd J(csize, xsize); // Jacobi of the subsystem
Eigen::VectorXd x(xsize), h(xsize), x_new(xsize), g(xsize);
Eigen::MatrixXd A;
Eigen::VectorXd diag_A(xsize);
Eigen::MatrixXd A(xsize, xsize);
Eigen::VectorXd x(xsize), h(xsize), x_new(xsize), g(xsize), diag_A(xsize);
subsys->redirectParams();
@ -627,17 +624,23 @@ int System::solve_LM(SubSystem* subsys)
subsys->calcResidual(e);
e*=-1;
int maxIterNumber = MaxIterations * xsize;
double diverging_lim = 1e6*e.squaredNorm() + 1e12;
double eps=1e-10, eps1=1e-80;
double tau=1e-3;
double nu=2, mu=0;
int k=0, stop=0;
for (k=0; k < itmax && !stop; ++k) {
int iter=0, stop=0;
for (iter=0; iter < maxIterNumber && !stop; ++iter) {
// check error
// (logari81) why not using:
// if (e.squaredNorm() <= eps) { // error is small
if (e.dot(e) <= eps) { // error is small
stop=1;
double err=e.squaredNorm();
if (err <= eps) { // error is small, Success
stop = 1;
break;
}
else if (err > diverging_lim || err != err) { // check for diverging and NaN
stop = 6;
break;
}
@ -648,64 +651,42 @@ int System::solve_LM(SubSystem* subsys)
g = J.transpose()*e;
// Compute ||J^T e||_inf
double g_inf = -DBL_EPSILON; // (logari81) is this initialization correct?
for (int i=0; i < xsize; i++) {
if (g_inf < g(i))
g_inf = g(i);
diag_A(i) = A(i,i); // save diagonal entries so that augmentation can be later canceled
}
// (logari81) to be replaced with (if max(abs(g)) == max(g)):
// g_inf = g.lpNorm<Eigen::Infinity>();
// diag_A = A.diagonal();
double g_inf = g.lpNorm<Eigen::Infinity>();
diag_A = A.diagonal(); // save diagonal entries so that augmentation can be later canceled
// check for convergence
if (g_inf <= eps1) {
stop=2;
stop = 2;
break;
}
// compute initial damping factor
if (k==0) {
double temp=-DBL_EPSILON;
for (int i=0; i < xsize; i++) {
double z=A(i,i);
if (z > temp) temp=z; // find max diagonal element
}
mu=tau*temp;
}
// (logari81) to be replaced with (diagonal of A is positive):
// if (k==0)
// mu = tau * A.diagonal().lpNorm<Eigen::Infinity>();
if (iter == 0)
mu = tau * A.diagonal().lpNorm<Eigen::Infinity>();
// determine increment using adaptive damping
while (1) {
// augment normal equations A = A+uI
for (int i=0; i < xsize; ++i)
A(i,i) += mu;
// (logari81) to be replaced with:
// mu = tau * A.diagonal().lpNorm<Eigen::Infinity>();
//solve augmented functions A*h=-g
h = A.fullPivLu().solve(g);
double rel_error = (A*h - g).norm() / g.norm();
// check if solving workes
// check if solving works
if (rel_error < 1e-5) {
// compute par's new estimate and ||d_par||^2
x_new = x + h;
double h_norm = h.dot(h);
// (logari81) why not using:
// h_norm = h.squaredNorm();
double h_norm = h.squaredNorm();
if (h_norm <= eps1*(x.norm()*eps1)) { // relative change in p is small, stop
// (logari81) why not write:
// if (h_norm <= eps1*eps1*x.norm()) { // relative change in p is small, stop
stop=3;
if (h_norm <= eps1*eps1*x.norm()) { // relative change in p is small, stop
stop = 3;
break;
}
else if (h_norm >= (x.norm()+eps1)/(DBL_EPSILON*DBL_EPSILON)) { // almost singular
stop=4;
stop = 4;
break;
}
@ -713,22 +694,12 @@ int System::solve_LM(SubSystem* subsys)
subsys->calcResidual(e_new);
e_new *= -1;
double error_new = e_new.dot(e_new);
double dF = e.dot(e) - error_new;
// (logari81) why not using:
// double error_new = e_new.squaredNorm();
// double dF = e.squaredNorm() - error_new;
double dF = e.squaredNorm() - e_new.squaredNorm();
double dL = h.dot(mu*h+g);
if (dF>0. && dL>0.) { // reduction in error, increment is accepted
double tmp=(2.0*dF/dL)-1.0;
tmp = 1.0 - pow(tmp, 3);
if (tmp <= 1./3.)
mu *= 1./3.;
else
mu *= tmp;
// (logari81) to be replaced with:
// mu *= std::max(1./3.,tmp);
double tmp=2*dF/dL-1.;
mu *= std::max(1./3., 1.-tmp*tmp*tmp);
nu=2;
// update par's estimate
@ -744,11 +715,11 @@ int System::solve_LM(SubSystem* subsys)
mu*=nu;
nu*=2.0;
for (int i=0; i < xsize; ++i) // restore diagonal J^T J entries
A(i,i)=diag_A(i);
A(i,i) = diag_A(i);
}
}
if (k >= itmax)
if (iter >= maxIterNumber)
stop = 5;
subsys->revertParams();
@ -760,13 +731,10 @@ int System::solve_LM(SubSystem* subsys)
int System::solve_DL(SubSystem* subsys)
{
double tolg=1e-80, tolx=1e-80, tolf=1e-10;
double error, error_new;
int xsize = subsys->pSize();
int csize = subsys->cSize();
int itmax = MaxIterations*xsize;
Eigen::VectorXd x(xsize), x_new(xsize);
Eigen::VectorXd fx(csize), fx_new(csize);
Eigen::MatrixXd Jx(csize, xsize), Jx_new(csize, xsize);
@ -774,46 +742,45 @@ int System::solve_DL(SubSystem* subsys)
subsys->redirectParams();
double err;
subsys->getParams(x);
subsys->calcResidual(fx, error);
subsys->calcResidual(fx, err);
subsys->calcJacobi(Jx);
g = -1*(Jx.transpose()*fx);
// (logari81) why not:
// g = Jx.transpose()*(-fx);
g = Jx.transpose()*(-fx);
// get the infinity norm fx_inf and g_inf
double fx_inf=0, g_inf=0;
for (int i=0; i < xsize; i++)
g_inf = fabs(g(i)) > g_inf ? fabs(g(i)) : g_inf;
for (int i=0; i < csize; i++)
fx_inf = fabs(fx(i)) > fx_inf ? fabs(fx(i)) : fx_inf;
// (logari81) to be replaced with:
// double g_inf = g.lpNorm<Eigen::Infinity>();
// double f_inf = f.lpNorm<Eigen::Infinity>();
double g_inf = g.lpNorm<Eigen::Infinity>();
double fx_inf = fx.lpNorm<Eigen::Infinity>();
int maxIterNumber = MaxIterations * xsize;
double diverging_lim = 1e6*err + 1e12;
double delta=0.1;
double alpha=0.;
double nu=2.;
int k=0, stop=0, reduce=0;
int iter=0, stop=0, reduce=0;
while (!stop) {
// check if finished
if (fx_inf <= tolf)
if (fx_inf <= tolf) // Success
stop = 1;
else if (g_inf <= tolg)
stop = 2;
else if (delta <= tolx*(tolx + x.norm()))
stop = 2;
else if (k >= itmax)
else if (iter >= maxIterNumber)
stop = 4;
else if (err > diverging_lim || err != err) { // check for diverging and NaN
stop = 6;
}
else {
// get the steepest descent direction
alpha = pow(g.norm()/(Jx*g).norm() ,2);
alpha = g.squaredNorm()/(Jx*g).squaredNorm();
h_sd = alpha*g;
// get the gauss-newton step
h_gn = Jx.fullPivLu().solve(-1*fx);
h_gn = Jx.fullPivLu().solve(-fx);
double rel_error = (Jx*h_gn + fx).norm() / fx.norm();
if (rel_error > 1e15)
break;
@ -838,9 +805,9 @@ int System::solve_DL(SubSystem* subsys)
double c = (delta + h_sd.norm())*(delta - h_sd.norm());
if (gb > 0)
beta = c / (gb + sqrt(pow(gb,2) + c * bb));
beta = c / (gb + sqrt(gb * gb + c * bb));
else
beta = (sqrt(pow(gb,2) + c * bb) - gb)/bb;
beta = (sqrt(gb * gb + c * bb) - gb)/bb;
// and update h_dl and dL with beta
h_dl = h_sd + beta*b;
@ -852,33 +819,28 @@ int System::solve_DL(SubSystem* subsys)
break;
// get the new values
double err_new;
x_new = x + h_dl;
subsys->setParams(x_new);
subsys->calcResidual(fx_new, error_new);
subsys->calcResidual(fx_new, err_new);
subsys->calcJacobi(Jx_new);
// calculate the linear model and the update ratio
double dL = error - 0.5*pow((fx + Jx*h_dl).norm(),2);
double dF = error - error_new;
double dL = err - 0.5*(fx + Jx*h_dl).squaredNorm();
double dF = err - err_new;
double rho = dL/dF;
if (dF > 0 && dL > 0) {
x = x_new;
Jx = Jx_new;
fx = fx_new;
error = error_new;
err = err_new;
g = -1*(Jx.transpose()*fx);
g = Jx.transpose()*(-fx);
// get infinity norms
fx_inf = g_inf = 0.;
for (int i=0; i < xsize; i++)
g_inf = fabs(g(i)) > g_inf ? fabs(g(i)) : g_inf;
for (int i=0; i < csize; i++)
fx_inf = fabs(fx(i)) > fx_inf ? fabs(fx(i)) : fx_inf;
// (logari81) to be replaced with:
// g_inf = g.lpNorm<Eigen::Infinity>();
// f_inf = f.lpNorm<Eigen::Infinity>();
g_inf = g.lpNorm<Eigen::Infinity>();
fx_inf = fx.lpNorm<Eigen::Infinity>();
}
else
rho = -1;
@ -898,7 +860,7 @@ int System::solve_DL(SubSystem* subsys)
reduce--;
// count this iteration and start again
k++;
iter++;
}
subsys->revertParams();