Keras: Confusion matrix at every epoch

Question

I am able to log the loss at every epoch using Keras Callback after referring this. Is there any way I can compute Confusion Matrix and use it as a metric?

Update I have tried to define the following function to return me the confusion matrix, but this is still not working.

def con_mat(y_true,y_pred):
    total_correct_true = K.sum(K.round(K.clip(y_true*y_pred,0,1)))
    total_true = K.sum(y_true)
    predicted_true = K.sum(K.round(y_pred))
    return (total_correct_true)/(total_true+predicted_true)

I think the logic for True positive is correct, but it is not working as expected.

Answer 1

Simply, just pass the following functions to model.compile function:

from keras import backend as K

def recall_m(y_true, y_pred): # TPR
    true_positives = K.sum(K.round(K.clip(y_true * y_pred, 0, 1))) # TP
    possible_positives = K.sum(K.round(K.clip(y_true, 0, 1))) # P
    recall = true_positives / (possible_positives + K.epsilon())
    return recall

def precision_m(y_true, y_pred):
    true_positives = K.sum(K.round(K.clip(y_true * y_pred, 0, 1))) # TP
    predicted_positives = K.sum(K.round(K.clip(y_pred, 0, 1))) # TP + FP
    precision = true_positives / (predicted_positives + K.epsilon())
    return precision

def f1_m(y_true, y_pred):
    precision = precision_m(y_true, y_pred)
    recall = recall_m(y_true, y_pred)
    return 2*((precision*recall)/(precision+recall+K.epsilon()))

def TP(y_true, y_pred):
    tp = K.sum(K.round(K.clip(y_true * y_pred, 0, 1))) # TP
    y_pos = K.round(K.clip(y_true, 0, 1))
    n_pos = K.sum(y_pos)
    y_neg = 1 - y_pos
    n_neg = K.sum(y_neg)
    n = n_pos + n_neg
    return tp/n

def TN(y_true, y_pred):
    y_pos = K.round(K.clip(y_true, 0, 1))
    n_pos = K.sum(y_pos)
    y_neg = 1 - y_pos
    n_neg = K.sum(y_neg)
    n = n_pos + n_neg
    y_pred_pos = K.round(K.clip(y_pred, 0, 1))
    y_pred_neg = 1 - y_pred_pos
    tn = K.sum(K.round(K.clip(y_neg * y_pred_neg, 0, 1))) # TN
    return tn/n

def FP(y_true, y_pred):
    y_pos = K.round(K.clip(y_true, 0, 1))
    n_pos = K.sum(y_pos)
    y_neg = 1 - y_pos
    n_neg = K.sum(y_neg)
    n = n_pos + n_neg
    tn = K.sum(K.round(K.clip(y_neg * y_pred, 0, 1))) # FP
    return tn/n

def FN(y_true, y_pred):
    y_pos = K.round(K.clip(y_true, 0, 1))
    n_pos = K.sum(y_pos)
    y_neg = 1 - y_pos
    n_neg = K.sum(y_neg)
    n = n_pos + n_neg
    y_pred_pos = K.round(K.clip(y_pred, 0, 1))
    y_pred_neg = 1 - y_pred_pos
    tn = K.sum(K.round(K.clip(y_true * y_pred_neg, 0, 1))) # FN
    return tn/n

Then,

model.compile(loss='binary_crossentropy',
          optimizer=optimizers.RMSprop(lr=lr),
          metrics=['accuracy',f1_m,precision_m, recall_m, TP, TN, FP, FN])

Answer 2

B"H

Here is a great example that I found

https://github.com/chasingbob/keras-visuals/blob/master/visual_callbacks.py