Custom conditional Keras metric

Question

Custom conditional Keras metric

Richard.R

2022年5月29日 03:07

I am trying to create the following metric for my neural network using keras

$$ s = \left\{ \begin{array}{ll} \sum_{i=1}^{n} e^{\frac{-d_i}{10}}-1 \quad d 0 \\ \sum_{i=1}^{n} e^{\frac{d_i}{13}}-1 \quad d \geq 0 \end{array} \right. $$ where $d_i=y_{pred}-y_{true}$

and both $y_{pred}$ and $y_{true}$ are vectors

With the following code:

import keras.backend as K

    def score(y_true, y_pred):
            d=(y_pred - y_true)
            if d0:
                return K.exp(-d/10)-1
            else:
                return K.exp(d/13)-1

For the use of compiling my model:

model.compile(loss='mse', optimizer='adam', metrics=[score])

I received the following error code and I have not been able to correct the issue. Any help would be appreciated.

raise TypeError("Using a tf.Tensor as a Python bool is not allowed. " "Use if t is not None: instead of if t: to test if a " "tensor is defined, and use TensorFlow ops such as "

TypeError: Using a tf.Tensor as a Python bool is not allowed. Use if t is not None: instead of if t: to test if a tensor is defined, and use TensorFlow ops such as tf.cond to execute subgraphs conditioned on the value of a tensor.

Topic keras tensorflow neural-network python machine-learning

Category Data Science

user8639163 · Accepted Answer · 2019年4月27日 03:55

def _loss_tensor_score(y_true, y_pred):
    y_error = y_pred - y_true
    bool_idx = K.greater(y_error, 0)
    loss1 = K.exp(-1*y_error/13) - 1 # greater 0
    loss2 = K.exp(y_error/10) - 1    # less 0
    loss = K.switch(bool_idx, loss2, loss1)
    return K.sum(loss)

Maybe you can try this code.

What are you doing? Remaining useful life prediction?

Matthew · Accepted Answer · 2018年8月20日 09:28

y_true and y_pred are both tensors in your code. Either change the code such that they're numpy arrays (I think this works) or look into tf.cond, which should allow you to do the operations you're looking for on tensors.

hssay · Accepted Answer · 2018年8月17日 04:54

I'm assuming y_true and y_pred both are vectors. You are trying to apply a conditional on the value of a tensor. The library is telling you that it is not possible (tf.Tensor as Python bool).

You may want to check tensorflow control flow operations like tensorflow.equal

Custom conditional Keras metric

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