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Nice Confusion Matrix with percentage cbar
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from matplotlib.ticker import PercentFormatter | |
import matplotlib.pyplot as plt | |
import seaborn as sns | |
from sklearn.metrics import confusion_matrix | |
def cm_analysis(y_true, y_pred, filename, labels, classes, ymap=None, figsize=(17,17)): | |
""" | |
Generate matrix plot of confusion matrix with pretty annotations. | |
The plot image is saved to disk. | |
args: | |
y_true: true label of the data, with shape (nsamples,) | |
y_pred: prediction of the data, with shape (nsamples,) | |
filename: filename of figure file to save | |
labels: string array, name the order of class labels in the confusion matrix. | |
use `clf.classes_` if using scikit-learn models. | |
with shape (nclass,). | |
classes: aliases for the labels. String array to be shown in the cm plot. | |
ymap: dict: any -> string, length == nclass. | |
if not None, map the labels & ys to more understandable strings. | |
Caution: original y_true, y_pred and labels must align. | |
figsize: the size of the figure plotted. | |
""" | |
sns.set(font_scale=2.8) | |
if ymap is not None: | |
y_pred = [ymap[yi] for yi in y_pred] | |
y_true = [ymap[yi] for yi in y_true] | |
labels = [ymap[yi] for yi in labels] | |
cm = confusion_matrix(y_true, y_pred, labels=labels) | |
cm_sum = np.sum(cm, axis=1, keepdims=True) | |
cm_perc = cm / cm_sum.astype(float) * 100 | |
annot = np.empty_like(cm).astype(str) | |
nrows, ncols = cm.shape | |
for i in range(nrows): | |
for j in range(ncols): | |
c = cm[i, j] | |
p = cm_perc[i, j] | |
if i == j: | |
s = cm_sum[i] | |
annot[i, j] = '%.2f%%\n%d/%d' % (p, c, s) | |
#elif c == 0: | |
# annot[i, j] = '' | |
else: | |
annot[i, j] = '%.2f%%\n%d' % (p, c) | |
cm = confusion_matrix(y_true, y_pred, labels=labels, normalize='true') | |
cm = pd.DataFrame(cm, index=labels, columns=labels) | |
cm = cm * 100 | |
cm.index.name = 'True Label' | |
cm.columns.name = 'Predicted Label' | |
fig, ax = plt.subplots(figsize=figsize) | |
plt.yticks(va='center') | |
sns.heatmap(cm, annot=annot, fmt='', ax=ax, xticklabels=classes, cbar=True, cbar_kws={'format':PercentFormatter()}, yticklabels=classes, cmap="Blues") | |
plt.savefig(filename, bbox_inches='tight') |
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