---
type: "Topics"
locale: "en"
url: "https://longbridge.com/en/topics/100000000925604.md"
description: "A classifier maps an input to a fixed set of labels.  The different kinds of classifiers include:🟠 Binary Classification: email ∈ {spam, not spam}🟠 Multiclass Classification: text ∈ {positive, neutral, negative} 🟠 Multilabel Classification: movie ⊆ {action, horror, comedy, romance, fantasy, thriller} It works by encoding the input into a vector either through hand-build features like logistic regression or a learned encoder like CNN or BERT.  It then projects that vector to K scores (logits) with a linear layer and applies a softmax/sigmoid function to turn the scores into probabilities and takes the vector with the highest probability. (1/3)🧵"
datetime: "2026-10-05T19:25:14.000Z"
locales:
  - [en](https://longbridge.com/en/topics/100000000925604.md)
  - [zh-CN](https://longbridge.com/zh-CN/topics/100000000925604.md)
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author: "[@SemiAnalysis](https://longbridge.com/en/profiles/2078041753485574144.md)"
generator: "portal-rs"
---

# A classifier maps an input to a fixed set of label…


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> **Disclaimer: This article is for reference only and does not constitute any investment advice.**