public static void DoFilterMonotony(this TableFunction tableFunction)
{
int length = tableFunction.X.Length;
double lastXStart = tableFunction.X[0];
Monotony lastMonotony = CheckMonotony(tableFunction.Y[0], tableFunction.Y[1]);
Monotony monotony = lastMonotony;
for (int i = 2; i < length; i++)
{
monotony = CheckMonotony(tableFunction.Y[i - 1], tableFunction.Y[i]);
if (lastMonotony == monotony)
{
continue;
}
else
{
tableFunction.cutsMonotonies.Add(new CutMomotony(lastXStart, tableFunction.X[i - 1],
lastMonotony));
lastMonotony = monotony;
lastXStart = tableFunction.X[i];
}
}
tableFunction.cutsMonotonies.Add(new CutMomotony(lastXStart, tableFunction.X[length - 1],
lastMonotony));
}
/// <summary>
/// Clasifies an extreme point acording to monotony
/// </summary>
/// <param name="previous">Monotony of the previous interval</param>
/// <param name="current">Monotony of the current interval</param>
/// <returns>Extreme point type</returns>
private static ExtremeType GetExtremeType(Monotony previous, Monotony current)
{
if (previous == Monotony.Grow && current == Monotony.Stable || previous == Monotony.Grow && current == Monotony.Abate || previous == Monotony.Stable && current == Monotony.Abate)
{
return(ExtremeType.Max);
}
if (previous == Monotony.Abate && current == Monotony.Stable || previous == Monotony.Abate && current == Monotony.Grow || previous == Monotony.Stable && current == Monotony.Grow)
{
return(ExtremeType.Min);
}
return(ExtremeType.None);
}
/// <summary>
/// Finds peaks and valleys in certain histogram
/// </summary>
/// <param name="histogram">Histogram involved</param>
/// <returns>Histogram's peaks and valleys</returns>
/// <remarks>Does not perform histogram normalization</remarks>
public static KeyValuePair <List <KeyValuePair <int, int> >, List <KeyValuePair <int, int> > > HistFind(double[] histogram)
{
// using var because static types are so darn long
var peaks = new List <KeyValuePair <int, int> >();
var valleys = new List <KeyValuePair <int, int> >();
var result = new KeyValuePair <List <KeyValuePair <int, int> >, List <KeyValuePair <int, int> > >(peaks, valleys);
// setting interval size
int dx = Dx;
// this is because there's always point shared betwwen intervals
int offset = dx - 1;
// there can not exist peaks or valleys (there's at most one interval)
if (dx < 2 || histogram.Length < 2 * offset + 1)
{
return(result);
}
// setting the smoothness of the curve
int smoothness = Smoothness;
// Ip: previous interval (Ip = [a, b])
// Ic: current interval (Ic = [b, c])
int a = 0;
int b = offset;
int c = b + offset;
// analyzing Ip monotony
Monotony ip_monotony = FindMonotony(histogram[a], histogram[b], dx);
// setting previous extreme point
ExtremeType previous_extreme = ExtremeType.None;
int previous_extreme_index = 1;
if (ip_monotony == Monotony.Abate)
{
previous_extreme = ExtremeType.Max;
}
else if (ip_monotony == Monotony.Grow)
{
previous_extreme = ExtremeType.Min;
}
// setting current extreme point
ExtremeType current_extreme = ExtremeType.None;
int current_extreme_index = 0;
// setting the first extreme point of the last registered shift
ExtremeType previous_shift_extreme = ExtremeType.None;
int previous_shift_extreme_index = 0;
// while the current interval is in range
while (c < histogram.Length)
{
// analyzing the monotony in Ic
Monotony ic_monotony = FindMonotony(histogram[b], histogram[c], dx);
// if there was a change in the monotony => there's a extreme
if (ip_monotony != ic_monotony)
{
// classifying the new extreme founded
current_extreme = GetExtremeType(ip_monotony, ic_monotony);
current_extreme_index = b;
// if there was a shift indeed
if (current_extreme != previous_extreme /*&& previous_extreme != ExtremeType.None*/)
{
// if this is not the first shift and phenomenon is smooth enough
if (previous_shift_extreme != ExtremeType.None && (current_extreme_index - previous_shift_extreme_index) / dx >= smoothness)
{
// we are in the presence of a VALLEY
if (previous_shift_extreme == ExtremeType.Max && current_extreme == ExtremeType.Max)
{
valleys.Add(new KeyValuePair <int, int>(previous_shift_extreme_index, current_extreme_index));
}
// we are in the presence of a PEAK
else if (previous_shift_extreme == ExtremeType.Min && current_extreme == ExtremeType.Min)
{
peaks.Add(new KeyValuePair <int, int>(previous_shift_extreme_index, current_extreme_index));
}
}
// update previous shift extreme
previous_shift_extreme = previous_extreme;
previous_shift_extreme_index = previous_extreme_index;
}
// updating previous extreme point
previous_extreme = current_extreme;
previous_extreme_index = current_extreme_index;
}
// updating intervals
a = b;
b = c;
c += offset;
// updating last interval monotony
ip_monotony = ic_monotony;
}
return(result);
}
public CutMomotony(double xStart, double xEnd, Monotony monotony)
{
this.xStart = xStart;
this.xEnd = xEnd;
this.monotony = monotony;
}