8000 [MRG] Fix aesthetic example roc crossval by glemaitre · Pull Request #8232 · scikit-learn/scikit-learn · GitHub
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[MRG] Fix aesthetic example roc crossval #8232

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35 changes: 21 additions & 14 deletions examples/model_selection/plot_roc_crossval.py
Original file line number Diff line number Diff line change
Expand Up @@ -62,32 +62,39 @@
classifier = svm.SVC(kernel='linear', probability=True,
random_state=random_state)

mean_tpr = 0.0
tprs = []
aucs = []
mean_fpr = np.linspace(0, 1, 100)

colors = cycle(['cyan', 'indigo', 'seagreen', 'yellow', 'blue', 'darkorange'])
lw = 2

i = 0
for (train, test), color in zip(cv.split(X, y), colors):
for train, test in cv.split(X, y):
probas_ = classifier.fit(X[train], y[train]).predict_proba(X[test])
# Compute ROC curve and area the curve
fpr, tpr, thresholds = roc_curve(y[test], probas_[:, 1])
mean_tpr += interp(mean_fpr, fpr, tpr)
mean_tpr[0] = 0.0
tprs.append(interp(mean_fpr, fpr, tpr))
tprs[-1][0] = 0.0
roc_auc = auc(fpr, tpr)
plt.plot(fpr, tpr, lw=lw, color=color,
label='ROC fold %d (area = %0.2f)' % (i, roc_auc))
aucs.append(roc_auc)
plt.plot(fpr, tpr, lw=1, alpha=0.3,
label='ROC fold %d (AUC = %0.2f)' % (i, roc_auc))

i += 1
plt.plot([0, 1], [0, 1], linestyle='--', lw=lw, color='k',
label='Luck')
plt.plot([0, 1], [0, 1], linestyle='--', lw=2, color='r',
label='Luck', alpha=.8)

mean_tpr /= cv.get_n_splits(X, y)
mean_tpr = np.mean(tprs, axis=0)
mean_tpr[-1] = 1.0
mean_auc = auc(mean_fpr, mean_tpr)
plt.plot(mean_fpr, mean_tpr, color='g', linestyle='--',
label='Mean ROC (area = %0.2f)' % mean_auc, lw=lw)
std_auc = np.std(aucs)
plt.plot(mean_fpr, mean_tpr, color='b',
label=r'Mean ROC (AUC = %0.2f $\pm$ %0.2f)' % (mean_auc, std_auc),
lw=2, alpha=.8)

std_tpr = np.std(tprs, axis=0)
tprs_upper = np.minimum(mean_tpr + std_tpr, 1)
tprs_lower = np.maximum(mean_tpr - std_tpr, 0)
plt.fill_between(mean_fpr, tprs_lower, tprs_upper, color='grey', alpha=.2,
label=r'$\pm$ 1 std. dev.')

plt.xlim([-0.05, 1.05])
plt.ylim([-0.05, 1.05])
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