FieldType<rank, dim> line_search(
const Functional& F,
const FieldType<rank, dim>& phi,
const FieldType<rank, dim, dual>& df,
const FieldType<rank, dim, primal>& p,
const double eps
)
{
// Compute the angle between the search direction and the gradient of the
// objective functional; we need this
const double theta = inner_product(df, p);
// Make a lambda function giving the value of the objective along the
// search direction.
const auto f = [&](const double alpha) { return F(phi + alpha * p); };
// Find an endpoint to bound the line search.
// TODO: make the parameters 1.0e-4, 0.5 adjustable, but default to the
// values given in Nocedal & Wright.
const double end_point = armijo(f, theta, 1.0e-4, 0.5);
// Locate the minimum of the objective functional along the search,
// within the bounds obtained using the Armijo rule.
const double alpha = golden_section_search(f, 0.0, end_point, eps);
return phi + alpha * p;
}
int rechne() {
//double temp = 0.0;
double *richtung;
double schritt = 0.0;
double x = start_x;
double y = start_y;
double z = start_z;
double x_neu = 0.0;
double y_neu = 0.0;
double z_neu = 0.0;
int i = 0;
//test(); //test-Daten
//double funkt = 0.0;
//funkt = f(x,y,z,n);
//printf("funktion: %lf\n",funkt);
while(i<2000)
{
//printf("iter:%d\n",i);
richtung = grad_f(x,y,z,n);
//printf("richtung: %lf ", richtung[0]);
//richtung[0] = -richtung[0];
//printf("richtung-neg: %lf ", richtung[0]);
//richtung[1] = -richtung[1];
//richtung[2] = -richtung[2];
schritt = armijo(x,y,z,n);
x_neu = x - schritt*richtung[0];
y_neu = y - schritt*richtung[1];
z_neu = z - schritt*richtung[2];
i++;
//auf Staionaritaet pruefen
if (((x-x_neu)*(x-x_neu)+(y-y_neu)*(y-y_neu)+(z-z_neu)*(z-z_neu))<0.0001)
break;
x = x_neu;
y = y_neu;
z = z_neu;
//funkt = f(x,y,z,n);
//printf("schritt: %lf ",schritt);
//temp = schritt*richtung[0];
//printf("multi: %lf\n", temp);
}
x = x_neu;
y = y_neu;
z = z_neu;
posx = x;
posy = y;
posz = z;
//printf("Iterationen: %i Position: x = %lf, y = %lf, z = %lf\n",i,x,y,z);
int ret = 0;
return ret;
}
//Start Berechnung der Koordinaten
void ips::rechne()
{
double richtung[3]={0};
double schritt = 0.0;
double x = start_x;
double y = start_y;
double z = start_z;
double x_neu = 0.0;
double y_neu = 0.0;
double z_neu = 0.0;
int i = 0;
while(i<300)
{
//Grad (google it!!)
gradf(x,y,z);
richtung[0] = erg[0];
richtung[1] = erg[1];
richtung[2] = erg[2];
//Schrittweite nach Armijo (google it!!)
schritt = armijo(x,y,z);
//qDebug() << schritt;
x_neu = x - schritt*richtung[0];
//qDebug() << x_neu;
y_neu = y - schritt*richtung[1];
z_neu = z - schritt*richtung[2];
i++;
//auf Staionaritaet pruefen
if (((x-x_neu)*(x-x_neu)+(y-y_neu)*(y-y_neu)+(z-z_neu)*(z-z_neu))<0.0001)
{ break;}
x = x_neu;
y = y_neu;
z = z_neu;
}
qDebug() << "Anzahl der Schleifen:" << i;
if(i==300)
{
posx=0;
posy=0;
posz=0;
qDebug()<< "Keine Annäherung in 300 Schritten möglich";
}
else
{
posx = x_neu;
posy = y_neu;
posz = z_neu;
}
}
