public static PointN MethodHookJivs(F function, PointN b1, VectorN h, double eps, double z = 0.1)
{
PointN x;
do
{
do
{
PointN xk = b1;
PointN b2 = HookJivsHelper.ExploringSearch(function, xk, h);
Console.WriteLine("> Exploring search ( xk{0} ) = b2{1}", xk.ToString(), b2.ToString());
do
{
Console.WriteLine("> Doing step xk = b1 + (b2 - b1) * 2, will give xk{0}", xk.ToString());
xk = b1 + (b2 - b1) * 2;
x = HookJivsHelper.ExploringSearch(function, xk, h);
Console.WriteLine("> Exploring search ( xk{0} ) = x{1}", xk.ToString(), x.ToString());
b1 = b2;
b2 = x;
} while (function.Value(x) < function.Value(b1));
} while (function.Value(x) > function.Value(b1));
if (h.Length <= eps)
{
break;
}
h = h * z;
}while(true);
return(b1);
}
public static void TestHookJivs()
{
Console.WriteLine("Method Hook Jivs");
PointN basicPoint = new PointN(100.0, 100.0);
VectorN h = new VectorN(1.0, 1.0);
const double eps = 0.001;
F minimizedFunction = new F((point) => 4 * Math.Pow(point.Coordinates[0] - 5.123, 2) + Math.Pow(point.Coordinates[1] - 6.789, 2));
PointN calculatedMinimum = MethodHookJivs.HookJivs.MethodHookJivs(minimizedFunction, basicPoint, h, eps);
PointN expectedMinimum = new PointN(new List <double> {
1.0, 1.0
});
Console.WriteLine("=================================================================");
Console.WriteLine("Minimum Point: {0} ", calculatedMinimum.ToString());
Console.WriteLine("F({0}) = {1}", calculatedMinimum.ToString(), minimizedFunction.Value(calculatedMinimum));
Console.WriteLine("Press enter to close...");
Console.ReadLine();
}
public static void TestRandomSearch()
{
Console.WriteLine("Method Random Search");
PointN basicPoint = new PointN(8.0, 9.0);
const double alpha = 1.618,
betta = 0.618,
t0 = 1,
R = 0.8;
const int N = 10,
M = 3;
F minimizedFunction = new F((point) => 4 * Math.Pow(point.Coordinates[0] - 5, 2) + Math.Pow(point.Coordinates[1] - 6, 2));
PointN calculatedMinimum = MethodRandomSearch.RandomSearch.MethodRandomSearch(minimizedFunction, basicPoint, alpha, betta, t0, R, N, M);
PointN expectedMinimum = new PointN(new List <double> {
1.0, 1.0
});
Console.WriteLine("=================================================================");
Console.WriteLine("Minimum Point: {0} ", calculatedMinimum.ToString());
Console.WriteLine("F({0}) = {1}", calculatedMinimum.ToString(), minimizedFunction.Value(calculatedMinimum));
Console.WriteLine("Press enter to close...");
Console.ReadLine();
}
/// <summary>
/// Метод случайного поиска для функции n переменных
/// </summary>
/// <param name="basicPoint">Начальная точка x0</param>
/// <param name="a">Коэффициент расширения (1;+inf): 1.618 </param>
/// <param name="b">Коэффициент сжатия (0;1): 0.618 </param>
/// <param name="M">Максимальное число неудачно выполненых испытаний на данной итерации :(3n)</param>
/// <param name="t0">Начальная величина шага</param>
/// <param name="R">Минимальная величина шага</param>
/// <param name="N">Максимальное число итераций</param>
/// <returns>Точка минимума</returns>
public static PointN MethodRandomSearch(F function, PointN basicPoint, double a, double b, double t0, double R, int N, int M)
{
double tk = t0; // Length of k-th step
PointN xk = basicPoint; // Опорная точка
PointN yj; // Точки, лежащие на гиперсфере радиуса tk с центром в точке xk
PointN zj; // Точка, получающаяся после прыжка
int dimensionsCount = basicPoint.Coordinates.Count;
int k = 0, j = 1;
do
{
// Step 2 Make random vector
VectorN randomVector = new VectorN(dimensionsCount);
MakeRandomVector(randomVector); // TODO What will be after this operator?
Console.WriteLine("> Generated random vector {0}", randomVector.ToString());
// Step 3 Find yj
yj = xk + (randomVector / randomVector.Length) * tk;
// Step 4
// Good step
bool isCurrentStepGood = function.Value(yj) < function.Value(xk);
bool isNextStepAlsoGood = false;
if (isCurrentStepGood)
{
Console.WriteLine("> Good step F(yj {0}) < F(xk {1})", yj.ToString(), xk.ToString());
zj = xk + (yj - xk) * a;
isNextStepAlsoGood = function.Value(zj) < function.Value(xk);
if (isNextStepAlsoGood)
{
Console.WriteLine("> Good direction F(zj {0}) < F(xk {1})", zj.ToString(), xk.ToString());
xk = zj;
tk *= a;
k++;
bool tooManyIterations = k == N;
if (tooManyIterations)
{
Console.WriteLine("Limit of iterations N = {0} exceeded", N);
return(xk);
}
else
{
j = 1;
}
}
}
// Bad step
if (!isCurrentStepGood || !isNextStepAlsoGood)
{
bool maxNumberOfFailsReached = j == M;
if (!maxNumberOfFailsReached)
{
j++;
}
else if (maxNumberOfFailsReached)
{
Console.WriteLine("Number of bad steps from this point is exceeded");
if (tk <= R)
{
Console.WriteLine("Step size (tk) is less than Low limit (R)");
return(xk);
}
else if (maxNumberOfFailsReached && tk > R)
{
Console.WriteLine("Increase step size (t0) and repeat search");
tk *= b;
j = 1;
}
}
}
} while (true);
}
