kopia lustrzana https://github.com/animator/learn-python
Updated maths formulas
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@ -12,7 +12,7 @@ MSE is one of the most commonly used cost functions, particularly in regression
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**Mathematical Formulation:**
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The MSE is defined as:
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$$ MSE = \frac{1}{n} \sum_{i=1}^{n} (y_i - \hat{y}_i)^2 $$
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$$MSE = \frac{1}{n} \sum_{i=1}^{n} (y_i - \hat{y}_i)^2$$
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Where:
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- \( n \) is the number of samples.
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- \( y_i \) is the actual value.
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@ -41,7 +41,7 @@ MAE is another commonly used cost function for regression tasks. It measures the
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**Mathematical Formulation:**
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The MAE is defined as:
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$$ MAE = \frac{1}{n} \sum_{i=1}^{n} |y_i - \hat{y}_i| $$
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$$MAE = \frac{1}{n} \sum_{i=1}^{n} |y_i - \hat{y}_i|$$
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Where:
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- \( n \) is the number of samples.
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- \( y_i \) is the actual value.
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@ -70,8 +70,11 @@ def mean_absolute_error(y_true, y_pred):
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Cross-entropy loss is commonly used in binary classification problems. It measures the dissimilarity between the true and predicted probability distributions.
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**Mathematical Formulation:**
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For binary classification, the cross-entropy loss is defined as:
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$$ \text{Cross-Entropy} = -\frac{1}{n} \sum_{i=1}^{n} [y_i \log(\hat{y}_i) + (1 - y_i) \log(1 - \hat{y}_i)] $$
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$$\text{Cross-Entropy} = -\frac{1}{n} \sum_{i=1}^{n} [y_i \log(\hat{y}_i) + (1 - y_i) \log(1 - \hat{y}_i)]$$
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Where:
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- \( n \) is the number of samples.
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- \( y_i \) is the actual class label (0 or 1).
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@ -100,8 +103,11 @@ def binary_cross_entropy(y_true, y_pred):
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For multiclass classification problems, the cross-entropy loss is adapted to handle multiple classes.
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**Mathematical Formulation:**
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The multiclass cross-entropy loss is defined as:
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$$ \text{Cross-Entropy} = -\frac{1}{n} \sum_{i=1}^{n} \sum_{c=1}^{C} y_{i,c} \log(\hat{y}_{i,c}) $$
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$$\text{Cross-Entropy} = -\frac{1}{n} \sum_{i=1}^{n} \sum_{c=1}^{C} y_{i,c} \log(\hat{y}_{i,c})$$
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Where:
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- \( n \) is the number of samples.
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- \( C \) is the number of classes.
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@ -131,8 +137,11 @@ def categorical_cross_entropy(y_true, y_pred):
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Hinge loss is commonly used in support vector machines (SVMs) for binary classification tasks. It penalizes misclassifications by a linear margin.
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**Mathematical Formulation:**
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For binary classification, the hinge loss is defined as:
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$$ \text{Hinge Loss} = \frac{1}{n} \sum_{i=1}^{n} \max(0, 1 - y_i \cdot \hat{y}_i) $$
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$$\text{Hinge Loss} = \frac{1}{n} \sum_{i=1}^{n} \max(0, 1 - y_i \cdot \hat{y}_i)$$
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Where:
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- \( n \) is the number of samples.
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- \( y_i \) is the actual class label (-1 or 1).
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@ -165,17 +174,16 @@ Huber loss is a combination of MSE and MAE, providing a compromise between the t
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The Huber loss is defined as:
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$$
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\text{Huber Loss} = \frac{1}{n} \sum_{i=1}^{n} \left\{
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$$\text{Huber Loss} = \frac{1}{n} \sum_{i=1}^{n} \left\{
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\begin{array}{ll}
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\frac{1}{2} (y_i - \hat{y}_i)^2 & \text{if } |y_i - \hat{y}_i| \leq \delta \\
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\delta(|y_i - \hat{y}_i| - \frac{1}{2} \delta) & \text{otherwise}
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\end{array}
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\right.
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$$
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\right.$$
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Where:
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- \( n \) is the number of samples.
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- \( \delta \) is a threshold parameter.
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- \(delta\) is a threshold parameter.
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**Advantages:**
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- Provides a smooth loss function.
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@ -200,8 +208,11 @@ def huber_loss(y_true, y_pred, delta):
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Log-Cosh loss is a smooth approximation of the MAE and is less sensitive to outliers than MSE. It provides a smooth transition from quadratic for small errors to linear for large errors.
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**Mathematical Formulation:**
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The Log-Cosh loss is defined as:
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$$ \text{Log-Cosh Loss} = \frac{1}{n} \sum_{i=1}^{n} \log(\cosh(y_i - \hat{y}_i)) $$
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$$\text{Log-Cosh Loss} = \frac{1}{n} \sum_{i=1}^{n} \log(\cosh(y_i - \hat{y}_i))$$
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Where:
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- \( n \) is the number of samples.
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