bool NOX::Direction::ModifiedNewton::
compute(NOX::Abstract::Vector& dir,
NOX::Abstract::Group& soln,
const NOX::Solver::Generic& solver)
{
NOX::Abstract::Group::ReturnType status;
// Compute F at current solution
status = soln.computeF();
if (status != NOX::Abstract::Group::Ok)
throwError("compute", "Unable to compute F");
maxAgeOfJacobian = paramsPtr->sublist("Modified-Newton").get("Max Age of Jacobian", 10);
if (Teuchos::is_null(oldJacobianGrpPtr)) {
oldJacobianGrpPtr = soln.clone(DeepCopy);
}
NOX::Abstract::Group& oldJacobianGrp = *oldJacobianGrpPtr;
status = NOX::Abstract::Group::Failed;
while (status != NOX::Abstract::Group::Ok) {
// Conditionally compute Jacobian at current solution.
if ( (ageOfJacobian == -1) || (ageOfJacobian == maxAgeOfJacobian) ) {
if (ageOfJacobian > 0)
oldJacobianGrp = soln;
status = oldJacobianGrp.computeJacobian();
if (status != NOX::Abstract::Group::Ok)
throwError("compute", "Unable to compute Jacobian");
ageOfJacobian = 1;
}
else
ageOfJacobian++;
// Compute the Modified Newton direction
status = oldJacobianGrp.applyJacobianInverse(paramsPtr->sublist("Modified-Newton").sublist("Linear Solver"), soln.getF(), dir);
dir.scale(-1.0);
// It didn't converge, but maybe we can recover.
if ((status != NOX::Abstract::Group::Ok) &&
(doRescue == false)) {
throwError("compute", "Unable to solve Newton system");
}
else if ((status != NOX::Abstract::Group::Ok) &&
(doRescue == true)) {
if (utils->isPrintType(NOX::Utils::Warning))
utils->out() << "WARNING: NOX::Direction::ModifiedNewton::compute() - "
<< "Linear solve failed to achieve convergence - "
<< "using the step anyway since \"Rescue Bad Newton Solve\" "
<< "is true. Also, flagging recompute of Jacobian." << std::endl;
ageOfJacobian = maxAgeOfJacobian;
status = NOX::Abstract::Group::Ok;
}
}
return true;
}
double NOX::MeritFunction::SumOfSquares::
computeSlopeWithoutJacobian(const NOX::Abstract::Vector& dir,
const NOX::Abstract::Group& grp) const
{
if (Teuchos::is_null(tmpVecPtr))
tmpVecPtr = grp.getF().clone(NOX::ShapeCopy);
if (Teuchos::is_null(tmpGrpPtr))
tmpGrpPtr = grp.clone(NOX::ShapeCopy);
// Compute the perturbation parameter
double lambda = 1.0e-6;
double denominator = dir.norm();
// Don't divide by zero
if (denominator == 0.0)
denominator = 1.0;
double eta = lambda * (lambda + grp.getX().norm() / denominator);
// Don't divide by zero
if (eta == 0.0)
eta = 1.0e-6;
// Perturb the solution vector
tmpVecPtr->update(eta, dir, 1.0, grp.getX(), 0.0);
// Compute the new F --> F(x + eta * dir)
tmpGrpPtr->setX(*(tmpVecPtr.get()));
tmpGrpPtr->computeF();
// Compute Js = (F(x + eta * dir) - F(x))/eta
tmpVecPtr->update(-1.0/eta, grp.getF(), 1.0/eta, tmpGrpPtr->getF(), 0.0);
return(tmpVecPtr->innerProduct(grp.getF()));
}
void MatrixFree::setGroupForComputeF(const NOX::Abstract::Group& group)
{
useGroupForComputeF = true;
groupPtr = group.clone();
return;
}
bool NOX::Direction::Broyden::compute(NOX::Abstract::Vector& dir,
NOX::Abstract::Group& soln,
const NOX::Solver::LineSearchBased& solver)
{
// Return value for group operations (temp variable)
NOX::Abstract::Group::ReturnType status;
// Compute F at current solution
status = soln.computeF();
if (status != NOX::Abstract::Group::Ok)
throwError("compute", "Unable to compute F");
// Check for restart
if (doRestart(soln, solver))
{
// Reset memory
memory.reset();
// Update group
if (Teuchos::is_null(oldJacobianGrpPtr))
oldJacobianGrpPtr = soln.clone(NOX::DeepCopy);
else
// RPP - update the entire group (this grabs state vectors in xyce).
// Otherwise, xyce is forced to recalculate F at each iteration.
//oldJacobianGrpPtr->setX(soln.getX());
*oldJacobianGrpPtr = soln;
// Calcuate new Jacobian
if (utils->isPrintType(NOX::Utils::Details))
utils->out() << " Recomputing Jacobian" << endl;
status = oldJacobianGrpPtr->computeJacobian();
if (status != NOX::Abstract::Group::Ok)
throwError("compute", "Unable to compute Jacobian");
// Reset counter
cnt = 0;
}
// If necesary, scale the s-vector from the last iteration
if (!memory.empty())
{
double step = solver.getStepSize();
memory[memory.size() - 1].setStep(step);
}
// --- Calculate the Broyden direction ---
// Compute inexact forcing term if requested.
inexactNewtonUtils.computeForcingTerm(soln,
solver.getPreviousSolutionGroup(),
solver.getNumIterations(),
solver);
// dir = - J_old^{-1} * F
cnt ++;
status = oldJacobianGrpPtr->applyJacobianInverse(*lsParamsPtr,
soln.getF(),
dir);
if (status != NOX::Abstract::Group::Ok)
throwError("compute", "Unable to apply Jacobian inverse");
dir.scale(-1.0);
// Apply the Broyden modifications to the old Jacobian (implicitly)
if (!memory.empty())
{
// Number of elements in the memory
int m = memory.size();
// Information corresponding to index i
double step;
Teuchos::RCP<const NOX::Abstract::Vector> sPtr;
// Information corresponding to index i + 1
// (initialized for i = -1)
double stepNext = memory[0].step();
Teuchos::RCP<const NOX::Abstract::Vector> sPtrNext =
memory[0].sPtr();
// Intermediate storage
double a, b, c, denom;
for (int i = 0; i < m-1; i ++)
{
step = stepNext;
sPtr = sPtrNext;
stepNext = memory[i+1].step();
sPtrNext = memory[i+1].sPtr();
a = step / stepNext;
b = step - 1;
c = sPtr->innerProduct(dir) / memory[i].sNormSqr();
dir.update(a * c, *sPtrNext, b * c, *sPtr, 1.0);
}
step = stepNext;
sPtr = sPtrNext;
a = sPtr->innerProduct(dir); // <s,z>
b = memory[m-1].sNormSqr(); // ||s||^2
c = (step - 1) * a; // (\lambda-1) <s,z>
denom = b - step * a; // ||s||^2 - \lambda <s,z>
dir.update(c / denom, *sPtr, b / denom);
}
//! Add this direction to the memory
memory.push(dir);
return true;
}
