public static double CalculateDerivative(Calculator calc, ParametricExpression expr, double t, out PointD result)
{
calc.GraphingArgumentValue = t;
double x1 = calc.Evaluate(expr.XExpression);
double y1 = calc.Evaluate(expr.YExpression);
calc.GraphingArgumentValue = t + DeltaX;
double x2 = calc.Evaluate(expr.XExpression);
double y2 = calc.Evaluate(expr.YExpression);
double fPrime1 = (x2 - x1) / DeltaX;
double fPrime2 = (y2 - y1) / DeltaX;
result = new PointD(x1, y1);
return fPrime2 / fPrime1;
}
private static PointD[] CalculateLine(Calculator calc, CalculatedLine line, double end, ref double pos)
{
if (pos > end)
{
throw new ArgumentException("The current position is greater than the end.");
}
int i = 0;
var filled = new PointD[(int)Math.Round(Math.Abs(end - pos) / line.Increment)];
while (end - pos > 1E-10 || pos < end)
{
calc.GraphingArgumentValue = pos;
filled[i++] = new PointD(pos * line.XScale,
calc.Evaluate(((StandardExpression)line.Expression).Expression) * line.YScale);
pos += line.Increment;
}
return filled;
}
public RoughSignificant(PointD left, PointD right)
{
Left = left;
Right = right;
}
private static void GetSurroundingPoints(IList<IList<PointD>> segments, int signifSegment, int signifPoint, out PointD left, out PointD right)
{
if (signifPoint == 0)
{
// Maximum is the first point in a segment
left = signifSegment == 0
? segments[signifSegment - 1][0]
: segments[signifSegment - 1].Last();
}
else
{
left = segments[signifSegment][signifPoint - 1];
}
if (signifPoint == segments[signifSegment].Count - 1)
{
// Maximum is the last point in a segment
right = signifSegment == segments.Count - 1
? segments[signifSegment].Last()
: segments[signifSegment + 1][0];
}
else
{
right = segments[signifSegment][signifPoint + 1];
}
}
private static RoughSignificant GetRoughSignificant(CalculatedLine line, Calculator calc, double leftBound, double rightBound, Mode mode)
{
IList<IList<PointD>> segments = line.PointData.Count > 1 ? GetCompleteLine(calc, line) : line.PointData;
double scaledLeftBound = leftBound * line.XScale;
double scaledRightBound = rightBound * line.XScale;
Func<double, double, bool> comparer = mode == Mode.Maximum ? _maxValComparer : _minValComparer;
var significant = new PointD(0, mode == Mode.Maximum ? double.MinValue : double.MaxValue);
int signifSegment = -1, signifPoint = -1;
for (int i = 0; i < segments.Count; i++)
{
var segment = segments[i];
for (int j = 0; j < segment.Count; j++)
{
var point = segment[j];
if (comparer(significant.Y, point.Y) && point.X >= scaledLeftBound && point.X <= scaledRightBound)
{
significant = point;
signifSegment = i;
signifPoint = j;
}
}
}
if (signifSegment == -1 || signifPoint == -1)
{
throw new Exception("No significant value could be found.");
}
// Get the points to the left and right of the rough maximum
PointD left;
PointD right;
GetSurroundingPoints(segments, signifSegment, signifPoint, out left, out right);
return new RoughSignificant(left, right);
}
public void AddPoint(PointD point)
{
_workingPointList.Add(point);
}