准确率 召回率 调和平均数等

		True	Class
		P	N
Hypothesized	Y	True Positive	False Positive
Class	N	False Nagative	Trure Nagative

P = TP + FN  正样本

N = TN + FP  负样本

TPR = TP / P 

FPR = FP / N

Precision = TP / (TP + FP)

Recall = TP / P

Accuary = (TP + TN)  / (P + N)

F-measure = 2Pre * Rec / (Pre + Rec)