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嵌入(Embeddings)将文本转换为数值向量,您可以将其存储在向量数据库中、使用余弦相似度进行搜索,或用于 RAG 流水线。向量长度取决于模型(通常为 384–1024 维)。

推荐模型

生成嵌入

CLI

直接从命令行生成嵌入:

shell
ollama run embeddinggemma "Hello world"

您还可以通过管道传递文本来生成嵌入:

shell
echo "Hello world" | ollama run embeddinggemma

输出为 JSON 数组。

cURL

shell
curl -X POST http://localhost:11434/api/embed \
  -H "Content-Type: application/json" \
  -d '{
    "model": "embeddinggemma",
    "input": "The quick brown fox jumps over the lazy dog."
  }'

Python

python
import ollama

single = ollama.embed(
  model='embeddinggemma',
  input='The quick brown fox jumps over the lazy dog.'
)
print(len(single['embeddings'][0]))  # vector length

JavaScript

javascript
import ollama from 'ollama'

const single = await ollama.embed({
  model: 'embeddinggemma',
  input: 'The quick brown fox jumps over the lazy dog.',
})
console.log(single.embeddings[0].length) // vector length

注意

/api/embed 端点返回经过 L2 归一化(单位长度)的向量。

生成批量嵌入

将字符串数组传递给 input

cURL

shell
curl -X POST http://localhost:11434/api/embed \
  -H "Content-Type: application/json" \
  -d '{
    "model": "embeddinggemma",
    "input": [
      "First sentence",
      "Second sentence",
      "Third sentence"
    ]
  }'

Python

python
import ollama

batch = ollama.embed(
  model='embeddinggemma',
  input=[
    'The quick brown fox jumps over the lazy dog.',
    'The five boxing wizards jump quickly.',
    'Jackdaws love my big sphinx of quartz.',
  ]
)
print(len(batch['embeddings']))  # number of vectors

JavaScript

javascript
import ollama from 'ollama'

const batch = await ollama.embed({
  model: 'embeddinggemma',
  input: [
    'The quick brown fox jumps over the lazy dog.',
    'The five boxing wizards jump quickly.',
    'Jackdaws love my big sphinx of quartz.',
  ],
})
console.log(batch.embeddings.length) // number of vectors

提示

  • 在大多数语义搜索场景中使用余弦相似度。
  • 在索引和查询时使用相同的嵌入模型。