public override EndCriteria.Type minimize(Problem P, EndCriteria endCriteria)
{
EndCriteria.Type ecType = EndCriteria.Type.None;
upperBound_ = P.constraint().upperBound(P.currentValue());
lowerBound_ = P.constraint().lowerBound(P.currentValue());
currGenSizeWeights_ = new Vector(configuration().populationMembers,
configuration().stepsizeWeight);
currGenCrossover_ = new Vector(configuration().populationMembers,
configuration().crossoverProbability);
List <Candidate> population = new InitializedList <Candidate>(configuration().populationMembers);
population.ForEach((ii, vv) => population[ii] = new Candidate(P.currentValue().size()));
fillInitialPopulation(population, P);
//original quantlib use partial_sort as only first elements is needed
double fxOld = population.Min(x => x.cost);
bestMemberEver_ = (Candidate)population.First(x => x.cost.IsEqual(fxOld)).Clone();
int iteration = 0, stationaryPointIteration = 0;
// main loop - calculate consecutive emerging populations
while (!endCriteria.checkMaxIterations(iteration++, ref ecType))
{
calculateNextGeneration(population, P.costFunction());
double fxNew = population.Min(x => x.cost);
Candidate tmp = (Candidate)population.First(x => x.cost.IsEqual(fxNew)).Clone();
if (fxNew < bestMemberEver_.cost)
{
bestMemberEver_ = tmp;
}
if (endCriteria.checkStationaryFunctionValue(fxOld, fxNew, ref stationaryPointIteration,
ref ecType))
{
break;
}
fxOld = fxNew;
}
P.setCurrentValue(bestMemberEver_.values);
P.setFunctionValue(bestMemberEver_.cost);
return(ecType);
}
//! solve the optimization problem P
public override EndCriteria.Type minimize(Problem P, EndCriteria endCriteria)
{
// Initializations
double ftol = endCriteria.functionEpsilon();
int maxStationaryStateIterations_ = endCriteria.maxStationaryStateIterations();
EndCriteria.Type ecType = EndCriteria.Type.None; // reset end criteria
P.reset(); // reset problem
Vector x_ = P.currentValue(); // store the starting point
int iterationNumber_ =0; // stationaryStateIterationNumber_=0
lineSearch_.searchDirection = new Vector(x_.Count); // dimension line search
bool done = false;
// function and squared norm of gradient values;
double fnew;
double fold;
double gold2;
double c;
double fdiff;
double normdiff;
// classical initial value for line-search step
double t = 1.0;
// Set gradient g at the size of the optimization problem search direction
int sz = lineSearch_.searchDirection.Count;
Vector g = new Vector(sz);
Vector d = new Vector(sz);
Vector sddiff = new Vector(sz);
// Initialize cost function, gradient g and search direction
P.setFunctionValue(P.valueAndGradient(g, x_));
P.setGradientNormValue(Vector.DotProduct(g, g));
lineSearch_.searchDirection = g * -1.0;
// Loop over iterations
do
{
// Linesearch
t = lineSearch_.value(P, ref ecType, endCriteria, t);
// don't throw: it can fail just because maxIterations exceeded
//QL_REQUIRE(lineSearch_->succeed(), "line-search failed!");
if (lineSearch_.succeed())
{
// Updates
d = lineSearch_.searchDirection;
// New point
x_ = lineSearch_.lastX();
// New function value
fold = P.functionValue();
P.setFunctionValue(lineSearch_.lastFunctionValue());
// New gradient and search direction vectors
g = lineSearch_.lastGradient();
// orthogonalization coef
gold2 = P.gradientNormValue();
P.setGradientNormValue(lineSearch_.lastGradientNorm2());
c = P.gradientNormValue() / gold2;
// conjugate gradient search direction
sddiff = ((g*-1.0) + c * d) - lineSearch_.searchDirection;
normdiff = Math.Sqrt(Vector.DotProduct(sddiff, sddiff));
lineSearch_.searchDirection = (g*-1.0) + c * d;
// Now compute accuracy and check end criteria
// Numerical Recipes exit strategy on fx (see NR in C++, p.423)
fnew = P.functionValue();
fdiff = 2.0 *Math.Abs(fnew-fold) / (Math.Abs(fnew) + Math.Abs(fold) + Double.Epsilon);
if (fdiff < ftol || endCriteria.checkMaxIterations(iterationNumber_, ref ecType))
{
endCriteria.checkStationaryFunctionValue(0.0, 0.0, ref maxStationaryStateIterations_, ref ecType);
endCriteria.checkMaxIterations(iterationNumber_, ref ecType);
return ecType;
}
//done = endCriteria(iterationNumber_,
// stationaryStateIterationNumber_,
// true, //FIXME: it should be in the problem
// fold,
// std::sqrt(gold2),
// P.functionValue(),
// std::sqrt(P.gradientNormValue()),
// ecType);
P.setCurrentValue(x_); // update problem current value
++iterationNumber_; // Increase iteration number
}
else
{
done =true;
}
} while (!done);
P.setCurrentValue(x_);
return ecType;
}
//! solve the optimization problem P
public override EndCriteria.Type minimize(Problem P, EndCriteria endCriteria)
{
// Initializations
double ftol = endCriteria.functionEpsilon();
int maxStationaryStateIterations_ = endCriteria.maxStationaryStateIterations();
EndCriteria.Type ecType = EndCriteria.Type.None; // reset end criteria
P.reset(); // reset problem
Vector x_ = P.currentValue(); // store the starting point
int iterationNumber_ = 0; // stationaryStateIterationNumber_=0
lineSearch_.searchDirection = new Vector(x_.Count); // dimension line search
bool done = false;
// function and squared norm of gradient values;
double fnew;
double fold;
double gold2;
double c;
double fdiff;
double normdiff;
// classical initial value for line-search step
double t = 1.0;
// Set gradient g at the size of the optimization problem search direction
int sz = lineSearch_.searchDirection.Count;
Vector g = new Vector(sz);
Vector d = new Vector(sz);
Vector sddiff = new Vector(sz);
// Initialize cost function, gradient g and search direction
P.setFunctionValue(P.valueAndGradient(g, x_));
P.setGradientNormValue(Vector.DotProduct(g, g));
lineSearch_.searchDirection = g * -1.0;
// Loop over iterations
do
{
// Linesearch
t = lineSearch_.value(P, ref ecType, endCriteria, t);
// don't throw: it can fail just because maxIterations exceeded
//QL_REQUIRE(lineSearch_->succeed(), "line-search failed!");
if (lineSearch_.succeed())
{
// Updates
d = lineSearch_.searchDirection;
// New point
x_ = lineSearch_.lastX();
// New function value
fold = P.functionValue();
P.setFunctionValue(lineSearch_.lastFunctionValue());
// New gradient and search direction vectors
g = lineSearch_.lastGradient();
// orthogonalization coef
gold2 = P.gradientNormValue();
P.setGradientNormValue(lineSearch_.lastGradientNorm2());
c = P.gradientNormValue() / gold2;
// conjugate gradient search direction
sddiff = ((g * -1.0) + c * d) - lineSearch_.searchDirection;
normdiff = Math.Sqrt(Vector.DotProduct(sddiff, sddiff));
lineSearch_.searchDirection = (g * -1.0) + c * d;
// Now compute accuracy and check end criteria
// Numerical Recipes exit strategy on fx (see NR in C++, p.423)
fnew = P.functionValue();
fdiff = 2.0 * Math.Abs(fnew - fold) / (Math.Abs(fnew) + Math.Abs(fold) + Double.Epsilon);
if (fdiff < ftol || endCriteria.checkMaxIterations(iterationNumber_, ref ecType))
{
endCriteria.checkStationaryFunctionValue(0.0, 0.0, ref maxStationaryStateIterations_, ref ecType);
endCriteria.checkMaxIterations(iterationNumber_, ref ecType);
return(ecType);
}
//done = endCriteria(iterationNumber_,
// stationaryStateIterationNumber_,
// true, //FIXME: it should be in the problem
// fold,
// std::sqrt(gold2),
// P.functionValue(),
// std::sqrt(P.gradientNormValue()),
// ecType);
P.setCurrentValue(x_); // update problem current value
++iterationNumber_; // Increase iteration number
}
else
{
done = true;
}
} while (!done);
P.setCurrentValue(x_);
return(ecType);
}
public override EndCriteria.Type minimize(Problem P, EndCriteria endCriteria)
{
// Initializations
double ftol = endCriteria.functionEpsilon();
int maxStationaryStateIterations_ = endCriteria.maxStationaryStateIterations();
EndCriteria.Type ecType = EndCriteria.Type.None; // reset end criteria
P.reset(); // reset problem
Vector x_ = P.currentValue(); // store the starting point
int iterationNumber_ = 0;
// dimension line search
lineSearch_.searchDirection = new Vector(x_.size());
bool done = false;
// function and squared norm of gradient values
double fnew, fold, gold2;
double fdiff;
// classical initial value for line-search step
double t = 1.0;
// Set gradient g at the size of the optimization problem
// search direction
int sz = lineSearch_.searchDirection.size();
Vector prevGradient = new Vector(sz), d = new Vector(sz), sddiff = new Vector(sz), direction = new Vector(sz);
// Initialize cost function, gradient prevGradient and search direction
P.setFunctionValue(P.valueAndGradient(prevGradient, x_));
P.setGradientNormValue(Vector.DotProduct(prevGradient, prevGradient));
lineSearch_.searchDirection = prevGradient * -1;
bool first_time = true;
// Loop over iterations
do
{
// Linesearch
if (!first_time)
{
prevGradient = lineSearch_.lastGradient();
}
t = (lineSearch_.value(P, ref ecType, endCriteria, t));
// don't throw: it can fail just because maxIterations exceeded
if (lineSearch_.succeed())
{
// Updates
// New point
x_ = lineSearch_.lastX();
// New function value
fold = P.functionValue();
P.setFunctionValue(lineSearch_.lastFunctionValue());
// New gradient and search direction vectors
// orthogonalization coef
gold2 = P.gradientNormValue();
P.setGradientNormValue(lineSearch_.lastGradientNorm2());
// conjugate gradient search direction
direction = getUpdatedDirection(P, gold2, prevGradient);
sddiff = direction - lineSearch_.searchDirection;
lineSearch_.searchDirection = direction;
// Now compute accuracy and check end criteria
// Numerical Recipes exit strategy on fx (see NR in C++, p.423)
fnew = P.functionValue();
fdiff = 2.0 * Math.Abs(fnew - fold) /
(Math.Abs(fnew) + Math.Abs(fold) + Const.QL_EPSILON);
if (fdiff < ftol ||
endCriteria.checkMaxIterations(iterationNumber_, ref ecType))
{
endCriteria.checkStationaryFunctionValue(0.0, 0.0, ref maxStationaryStateIterations_, ref ecType);
endCriteria.checkMaxIterations(iterationNumber_, ref ecType);
return(ecType);
}
P.setCurrentValue(x_); // update problem current value
++iterationNumber_; // Increase iteration number
first_time = false;
}
else
{
done = true;
}
}while (!done);
P.setCurrentValue(x_);
return(ecType);
}
