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| data_mining:neural_network:loss_functions [2019/11/09 23:22] – phreazer | data_mining:neural_network:loss_functions [2019/11/09 23:40] (current) – [Binary cross entropy] phreazer | ||
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| For an algo we need to find closes $p$ for $q$ by minimizing cross-entropy. | For an algo we need to find closes $p$ for $q$ by minimizing cross-entropy. | ||
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| + | In training we have $N$ samples. For one particular example the distribution is known to which class it belongs. The loss function should minimize the average cross-entropy. | ||
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| + | Outcome: Scalar [0,1] using sigmoid | ||
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| + | ===== Cross-entropy ===== | ||
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| + | $-\sum_{i}^C(y_i log(\hat{y_i})$ | ||
| + | $C$ is number of classes | ||
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| + | Outcome: Vector [0,1] using softmax | ||
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| + | ===== Binary cross entropy with multi labels ===== | ||
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| + | $-\sum_{i}^C(y_i log(\hat{y_i}) + (1-y_i) log(1-\hat{y_i})$ | ||
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| + | Ouctome: Vector [0,1] using sigmoid | ||
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