public void Compute(ROCCurve ROC, ErrorPolicy.Evaluate policy)
{
FindMinMax(ROC, policy, out Min, out Max);
float fraction = FindZeroFraction(policy(Min), policy(Max));
Rate.FAR = Calc.Interpolate(Min.FAR, Max.FAR, fraction);
Rate.FRR = Calc.Interpolate(Min.FRR, Max.FRR, fraction);
Rate.Threshold = Calc.Interpolate(Min.Threshold, Max.Threshold, fraction);
}
bool FindZeroPoint(ROCCurve ROC, ErrorPolicy.Evaluate policy, ref ROCPoint left, ref ROCPoint right)
{
for (int i = 0; i < ROC.Curve.Count; ++i)
{
if (policy(ROC.Curve[i]) == 0)
{
left = right = ROC.Curve[i];
return(true);
}
}
return(false);
}
void FindMinMax(ROCCurve ROC, ErrorPolicy.Evaluate policy, out ROCPoint left, out ROCPoint right)
{
left = new ROCPoint();
right = new ROCPoint();
if (CheckForNoZero(ROC, policy, ref left, ref right))
{
return;
}
if (FindZeroPoint(ROC, policy, ref left, ref right))
{
return;
}
if (FindZeroPair(ROC, policy, ref left, ref right))
{
return;
}
throw new AssertException();
}
bool CheckForNoZero(ROCCurve ROC, ErrorPolicy.Evaluate policy, ref ROCPoint left, ref ROCPoint right)
{
float first = policy(ROC.Curve[0]);
float last = policy(ROC.Curve[ROC.Curve.Count - 1]);
if (first > 0 && last > 0 || first < 0 && last < 0)
{
if (Math.Abs(first) < Math.Abs(last))
{
left = right = ROC.Curve[0];
}
else
{
left = right = ROC.Curve[ROC.Curve.Count - 1];
}
return(true);
}
return(false);
}