1
0
Fork 0
QuaPy/MultiLabel/util/metrics.py

87 lines
2.6 KiB
Python
Executable File

import numpy as np
from scipy.sparse import lil_matrix, issparse
from sklearn.metrics import f1_score, accuracy_score
"""
Scikit learn provides a full set of evaluation metrics, but they treat special cases differently.
I.e., when the number of true positives, false positives, and false negatives ammount to 0, all
affected metrices (precision, recall, and thus f1) output 0 in Scikit learn.
We adhere to the common practice of outputting 1 in this case since the classifier has correctly
classified all examples as negatives.
"""
def evaluation(y_true, y_pred, classification_type):
if classification_type == 'multilabel':
eval_function = multilabel_eval
elif classification_type == 'singlelabel':
eval_function = singlelabel_eval
Mf1, mf1, accuracy = eval_function(y_true, y_pred)
return Mf1, mf1, accuracy
def multilabel_eval(y, y_):
tp = y.multiply(y_)
fn = lil_matrix(y.shape)
true_ones = y==1
fn[true_ones]=1-tp[true_ones]
fp = lil_matrix(y.shape)
pred_ones = y_==1
if pred_ones.nnz>0:
fp[pred_ones]=1-tp[pred_ones]
#macro-f1
tp_macro = np.asarray(tp.sum(axis=0), dtype=int).flatten()
fn_macro = np.asarray(fn.sum(axis=0), dtype=int).flatten()
fp_macro = np.asarray(fp.sum(axis=0), dtype=int).flatten()
pos_pred = tp_macro+fp_macro
pos_true = tp_macro+fn_macro
prec=np.zeros(shape=tp_macro.shape,dtype=float)
rec=np.zeros(shape=tp_macro.shape,dtype=float)
np.divide(tp_macro, pos_pred, out=prec, where=pos_pred>0)
np.divide(tp_macro, pos_true, out=rec, where=pos_true>0)
den=prec+rec
macrof1=np.zeros(shape=tp_macro.shape,dtype=float)
np.divide(np.multiply(prec,rec),den,out=macrof1,where=den>0)
macrof1 *=2
macrof1[(pos_pred==0)*(pos_true==0)]=1
macrof1 = np.mean(macrof1)
#micro-f1
tp_micro = tp_macro.sum()
fn_micro = fn_macro.sum()
fp_micro = fp_macro.sum()
pos_pred = tp_micro + fp_micro
pos_true = tp_micro + fn_micro
prec = (tp_micro / pos_pred) if pos_pred>0 else 0
rec = (tp_micro / pos_true) if pos_true>0 else 0
den = prec+rec
microf1 = 2*prec*rec/den if den>0 else 0
if pos_pred==pos_true==0:
microf1=1
#accuracy
ndecisions = np.multiply(*y.shape)
tn = ndecisions - (tp_micro+fn_micro+fp_micro)
acc = (tp_micro+tn)/ndecisions
return macrof1,microf1,acc
def singlelabel_eval(y, y_):
if issparse(y_): y_ = y_.toarray().flatten()
macrof1 = f1_score(y, y_, average='macro')
microf1 = f1_score(y, y_, average='micro')
acc = accuracy_score(y, y_)
return macrof1,microf1,acc