# Softmax Regression (C2W3L08) | Summary and Q&A

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August 25, 2017
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DeepLearningAI
Softmax Regression (C2W3L08)

## TL;DR

Softmax regression is a generalization of logistic regression that allows for the recognition of multiple classes through the use of a softmax layer in the output.

## Key Insights

• 🏛️ Softmax regression is a technique used for multi-class classification problems.
• 🏛️ The softmax layer in the output of the neural network assigns probabilities to each class.
• 🍹 The softmax activation function ensures that these probabilities sum to one.
• 🏛️ Softmax regression can represent linear decision boundaries between classes.
• 🚱 With deeper neural networks, softmax regression can learn more complex non-linear decision boundaries.
• 🏛️ Softmax regression is used in various fields where multi-class classification is required.
• 🥡 The softmax activation function takes in a vector of inputs and outputs a vector of probabilities.

## Transcript

so far the classification examples we've talked about have used binary classification where you had two possible labels zero or one is in a cat as an alley cat what if you have multiple possible classes there's a generalization of logistic regression called softmax regression that lets you make predictions where you're trying to recognize one of c ... Read More

### Q: What is softmax regression used for?

Softmax regression is used for multi-class classification tasks, where there are more than two possible classes to categorize inputs into.

### Q: How is the output layer of the neural network structured in softmax regression?

The output layer has multiple units, each representing the probability of one of the classes. The number of units in the output layer is equal to the number of classes.

### Q: What is the softmax activation function?

The softmax activation function is applied to the linear part of the output layer. It takes in a vector of inputs and outputs a vector with normalized probabilities, ensuring that they sum to one.

### Q: Can softmax regression handle non-linear decision boundaries between classes?

Yes, softmax regression can handle non-linear decision boundaries if the neural network has hidden layers. With more complex architectures, it can learn more intricate decision boundaries.

## Summary & Key Takeaways

• Softmax regression is used when there are multiple possible classes to categorize inputs into.

• The output layer of the neural network has multiple units, each representing the probability of one of the classes.

• The softmax activation function is applied to the linear part of the output layer to generate these probabilities.