def getROCArea(cls, tcurve: Instances):
n = tcurve.numInstances()
if cls.RELATION_NAME != tcurve.relationName() or n == 0:
return float('nan')
tpInd = tcurve.attribute(cls.TRUE_POS_NAME).index()
fpInd = tcurve.attribute(cls.FALSE_POS_NAME).index()
tpVals = tcurve.attributeToDoubleArray(tpInd)
fpVals = tcurve.attributeToDoubleArray(fpInd)
area = cumNeg = 0
totalPos = tpVals[0]
totalNeg = fpVals[0]
for i in range(n):
if i < n - 1:
cip = tpVals[i] - tpVals[i + 1]
cin = fpVals[i] - fpVals[i + 1]
else:
cip = tpVals[n - 1]
cin = fpVals[n - 1]
area += cip * (cumNeg + (0.5 * cin))
cumNeg += cin
if totalNeg * totalPos == 0:
if area == 0:
return float("nan")
elif area > 0:
return float("inf")
else:
return float("-inf")
area /= (totalNeg * totalPos)
return area
def getPRCArea(cls, tcurve: Instances):
n = tcurve.numInstances()
if cls.RELATION_NAME != tcurve.relationName() or n == 0:
return float('nan')
pInd = tcurve.attribute(cls.PRECISION_NAME).index()
rInd = tcurve.attribute(cls.RECALL_NAME).index()
pVals = tcurve.attributeToDoubleArray(pInd)
rVals = tcurve.attributeToDoubleArray(rInd)
area = 0
xlast = rVals[n - 1]
for i in range(n - 2, -1, -1):
recallDelta = rVals[i] - xlast
area += pVals[i] * recallDelta
xlast = rVals[i]
if area == 0:
return Utils.missingValue()
return area
