---
metadata:
  - name: generator
    content: Diplodoc Platform v5.54.5
alternate:
  - https://catboost.ai/docs/en/concepts/algorithm-main-stages_pre-count.md
  - href: en/concepts/algorithm-main-stages_pre-count.md
    type: text/markdown
    title: Markdown version
  - href: ../llms.txt
    type: text/markdown
    title: llms.txt
---
> **Documentation Index:** Fetch the complete configuration index at https://catboost.ai/docs/en/llms.txt

# Preliminary calculation of splits

[Quantization](https://catboost.ai/docs/en/concepts/quantization.md) is performed for each numerical feature to determine the possible ways to _split_ data into _buckets_. The resulting information is used for [choosing the tree structure](https://catboost.ai/docs/en/concepts/algorithm-main-stages_choose-tree-structure.md).

The quantization method and number of buckets are set in the starting parameters.