/// <summary>
/// Computes a ROC curve with 1/increment points
/// </summary>
/// <param name="increment">The increment over the previous point for each point in the curve.</param>
/// <param name="forceOrigin">True to force the inclusion of the (0,0) point, false otherwise. Default is false.</param>
public void Compute(double increment, bool forceOrigin)
{
var points = new List <ReceiverOperatingCharacteristicPoint>();
double cutoff;
// Create the curve, computing a point for each cutoff value
for (cutoff = dfalse; cutoff <= dtrue; cutoff += increment)
{
points.Add(ComputePoint(cutoff));
}
// Sort the curve by descending specificity
points.Sort(new Comparison <ReceiverOperatingCharacteristicPoint>(
delegate(ReceiverOperatingCharacteristicPoint a, ReceiverOperatingCharacteristicPoint b)
{
// First order by descending specifity
int c = a.Specificity.CompareTo(b.Specificity);
if (c == 0) // then order by ascending sensitivity
{
return(a.Sensitivity.CompareTo(b.Sensitivity));
}
else
{
return(c);
}
}
));
if (forceOrigin)
{
var last = points[points.Count - 1];
if (last.FalsePositiveRate != 0.0 || last.Sensitivity != 0.0)
{
points.Add(ComputePoint(Double.PositiveInfinity));
}
}
// Create the point collection
this.collection = new ReceiverOperatingCharacteristicPointCollection(points.ToArray());
// Calculate area and error associated with this curve
this.area = calculateAreaUnderCurve();
this.error = calculateStandardError();
}
/// <summary>
/// Computes a ROC curve with the given increment points
/// </summary>
public void Compute(params double[] cutpoints)
{
List <ReceiverOperatingCharacteristicPoint> points = new List <ReceiverOperatingCharacteristicPoint>();
// Create the curve, computing a point for each cutpoint
for (int i = 0; i < cutpoints.Length; i++)
{
points.Add(ComputePoint(cutpoints[i]));
}
// Sort the curve by descending specificity
points.Sort(new Comparison <ReceiverOperatingCharacteristicPoint>(
delegate(ReceiverOperatingCharacteristicPoint a, ReceiverOperatingCharacteristicPoint b)
{
// First order by descending specifity
int c = a.Specificity.CompareTo(b.Specificity);
if (c == 0) // then order by ascending sensitivity
{
return(a.Sensitivity.CompareTo(b.Sensitivity));
}
else
{
return(c);
}
}
));
// Create the point collection
this.collection = new ReceiverOperatingCharacteristicPointCollection(points.ToArray());
// Calculate area and error associated with this curve
this.area = calculateAreaUnderCurve();
this.error = calculateStandardError();
}
