public void TestSingleDatapointAsTwoInLinearDoubleInterpolable()
{
LinearDoubleInterpolator ldi = new LinearDoubleInterpolator();
ldi.SetData(new double[] { 1.0, 1.1 }, new double[] { 5.0, 5.0 });
double five_point_zero = ldi.GetYValue(123.0);
Assert.IsTrue(five_point_zero == 5.0);
}
/// <summary>
/// Gets the percentile for item. Note: with [0,1,2,3,3,3], 3 will be in the 50th percentile.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="srcItems">The _SRC items.</param>
/// <param name="targetItem">The target item.</param>
/// <param name="valueGetter">The value getter.</param>
/// <param name="pd">The object that will hold state for repeated calls to this method on the same list.</param>
/// <returns></returns>
public static double GetPercentileForItem <T>(this List <T> srcItems, T targetItem, Func <T, double> valueGetter, ref object pd)
{
if (pd == null)
{
List <T> lclSrcItems = new List <T>(srcItems);
lclSrcItems.Sort((t1, t2) => Comparer <double> .Default.Compare(valueGetter(t1), valueGetter(t2)));
int nItems = lclSrcItems.Count;
// Added the following to collapse repeated xvalues (with which it is impossible
// to calculate a slope, dy/dx because dx==0).
List <double> data = new List <double>();
List <double> percentiles = new List <double>();
for (int i = 0; i < nItems; i++)
{
double xval = valueGetter(lclSrcItems[i]);
if (data.Count == 0 || xval != data.Last())
{
data.Add(xval);
percentiles.Add(((double)i + 1) / nItems);
}
}
// The preceding was added.
//double[] data = new double[nItems];
//double[] percentiles = new double[nItems];
//for (int i = 0; i < nItems; i++) {
// data[i] = valueGetter(srcItems[i]);
// percentiles[i] = ((double)i+1) / ((double)nItems);
//}
LinearDoubleInterpolator ldi = new LinearDoubleInterpolator();
//ldi.SetData(data, percentiles);
//_pd = new PercentileData() { min = data[0], ldi = ldi };
ldi.SetData(data.ToArray(), percentiles.ToArray());
pd = new PercentileData()
{
Min = data[0], Ldi = ldi
};
}
PercentileData lclPd = (PercentileData)pd;
return(Math.Max(0, Math.Min(1, lclPd.Ldi.GetYValue(valueGetter(targetItem)))));
}