private static Int32 Compare(fsIntegrationSegment a, fsIntegrationSegment b)
{
int compareResult = Compare(a.GetPriority(), b.GetPriority());
if (compareResult != 0)
{
return(compareResult);
}
compareResult = Compare(a.KronrodIntergralValue, b.KronrodIntergralValue);
if (compareResult != 0)
{
return(compareResult);
}
compareResult = Compare(a.GaussIntergralValue, b.GaussIntergralValue);
if (compareResult != 0)
{
return(compareResult);
}
compareResult = Compare(a.BeginArg, b.BeginArg);
if (compareResult != 0)
{
return(compareResult);
}
compareResult = Compare(a.EndArg, b.EndArg);
if (compareResult != 0)
{
return(compareResult);
}
return(0);
}
public static fsValue Calculate(fsFunction function, fsValue beginArg, fsValue endArg, fsValue tolerance)
{
if (beginArg > endArg)
{
throw new Exception("fsDefiniteIntegral: provided limits are: beginAng > endArg");
}
if (beginArg == endArg)
{
return(fsValue.Zero);
}
fsValue kronrodValue, gaussValue;
EvalIntegrals(function, beginArg, endArg, out kronrodValue, out gaussValue);
fsValue kronrodResult = kronrodValue;
fsValue gaussResult = gaussValue;
var queue = new SortedDictionary <fsIntegrationSegment, int>
{
{ new fsIntegrationSegment(kronrodValue, gaussValue, beginArg, endArg), 0 }
};
int iterationsCount = 0;
while (fsValue.Abs(kronrodResult - gaussResult) > tolerance ||
fsValue.Abs(kronrodResult / gaussResult - 1) > tolerance)
{
if (++iterationsCount >= 1000) // If we made too many iterations
{ // and still don't have proper precision
break; // then just return not precise answer.
}
fsIntegrationSegment currentSegment = queue.Last().Key;
queue.Remove(currentSegment);
beginArg = currentSegment.BeginArg;
endArg = currentSegment.EndArg;
if (IsNeighbouringNumbers(beginArg, endArg))
{
continue;
}
kronrodResult -= currentSegment.KronrodIntergralValue;
gaussResult -= currentSegment.GaussIntergralValue;
EvalIntegrals(function, beginArg, 0.5 * (beginArg + endArg), out kronrodValue, out gaussValue);
kronrodResult += kronrodValue;
gaussResult += gaussValue;
queue.Add(new fsIntegrationSegment(kronrodValue, gaussValue, beginArg, 0.5 * (beginArg + endArg)), 0);
EvalIntegrals(function, 0.5 * (beginArg + endArg), endArg, out kronrodValue, out gaussValue);
kronrodResult += kronrodValue;
gaussResult += gaussValue;
queue.Add(new fsIntegrationSegment(kronrodValue, gaussValue, 0.5 * (beginArg + endArg), endArg), 0);
}
return((kronrodResult + gaussResult) / 2);
}
