private static double BinarySearchInternal(double left, double right, ExaminedDoubleFunction function, bool ascendingFunction, params object[] hiddenParams)
{
for (; ; )
{
double middlePoint = (left + right) / 2.0f;
if ((middlePoint <= left) || (middlePoint >= right))
return middlePoint;
double middleValue = function(middlePoint, hiddenParams);
if (ascendingFunction)
{
if (Math.Sign(middleValue) < 0)
left = middlePoint;
else
right = middlePoint;
}
else
{
if (Math.Sign(middleValue) > 0)
left = middlePoint;
else
right = middlePoint;
}
}
}
/// <summary>
/// Binary search algorithm to search for solution of f(x) = 0.
/// </summary>
/// <param name="left">Left start point.</param>
/// <param name="right">Right start point.</param>
/// <param name="function">Delegate of the function f.</param>
/// <param name="hiddenParams">Parameters to be passed to the examinated function f.</param>
/// <returns>The point between left and right start point, where f(x) = 0.</returns>
public static double BinarySearch(double left, double right, ExaminedDoubleFunction function, params object[] hiddenParams)
{
// check arguments
if (left >= right)
throw new ArgumentException("The left point must be less than the right point.");
// verify the left and right points
double leftValue = function(left, hiddenParams);
double rightValue = function(right, hiddenParams);
bool ascendingFunction = (rightValue > leftValue);
if (Math.Sign(leftValue) == Math.Sign(rightValue))
throw new ArgumentException("The function must have different signs at the left and right points.");
// it is ok to start now...
return BinarySearchInternal(left, right, function, ascendingFunction, hiddenParams);
}
