"""Ollama embeddings models."""
from typing import Any, Dict, List, Optional
from langchain_core.embeddings import Embeddings
from ollama import AsyncClient, Client
from pydantic import (
BaseModel,
ConfigDict,
PrivateAttr,
model_validator,
)
from typing_extensions import Self
[docs]
class OllamaEmbeddings(BaseModel, Embeddings):
"""Ollama embedding model integration.
Set up a local Ollama instance:
Install the Ollama package and set up a local Ollama instance
using the instructions here: https://github.com/ollama/ollama .
You will need to choose a model to serve.
You can view a list of available models via the model library (https://ollama.com/library).
To fetch a model from the Ollama model library use ``ollama pull <name-of-model>``.
For example, to pull the llama3 model:
.. code-block:: bash
ollama pull llama3
This will download the default tagged version of the model.
Typically, the default points to the latest, smallest sized-parameter model.
* On Mac, the models will be downloaded to ~/.ollama/models
* On Linux (or WSL), the models will be stored at /usr/share/ollama/.ollama/models
You can specify the exact version of the model of interest
as such ``ollama pull vicuna:13b-v1.5-16k-q4_0``.
To view pulled models:
.. code-block:: bash
ollama list
To start serving:
.. code-block:: bash
ollama serve
View the Ollama documentation for more commands.
.. code-block:: bash
ollama help
Install the langchain-ollama integration package:
.. code-block:: bash
pip install -U langchain_ollama
Key init args — completion params:
model: str
Name of Ollama model to use.
base_url: Optional[str]
Base url the model is hosted under.
See full list of supported init args and their descriptions in the params section.
Instantiate:
.. code-block:: python
from langchain_ollama import OllamaEmbeddings
embed = OllamaEmbeddings(
model="llama3"
)
Embed single text:
.. code-block:: python
input_text = "The meaning of life is 42"
vector = embed.embed_query(input_text)
print(vector[:3])
.. code-block:: python
[-0.024603435769677162, -0.007543657906353474, 0.0039630369283258915]
Embed multiple texts:
.. code-block:: python
input_texts = ["Document 1...", "Document 2..."]
vectors = embed.embed_documents(input_texts)
print(len(vectors))
# The first 3 coordinates for the first vector
print(vectors[0][:3])
.. code-block:: python
2
[-0.024603435769677162, -0.007543657906353474, 0.0039630369283258915]
Async:
.. code-block:: python
vector = await embed.aembed_query(input_text)
print(vector[:3])
# multiple:
# await embed.aembed_documents(input_texts)
.. code-block:: python
[-0.009100092574954033, 0.005071679595857859, -0.0029193938244134188]
""" # noqa: E501
model: str
"""Model name to use."""
base_url: Optional[str] = None
"""Base url the model is hosted under."""
client_kwargs: Optional[dict] = {}
"""Additional kwargs to pass to the httpx Client.
For a full list of the params, see [this link](https://pydoc.dev/httpx/latest/httpx.Client.html)
"""
_client: Client = PrivateAttr(default=None) # type: ignore
"""
The client to use for making requests.
"""
_async_client: AsyncClient = PrivateAttr(default=None) # type: ignore
"""
The async client to use for making requests.
"""
mirostat: Optional[int] = None
"""Enable Mirostat sampling for controlling perplexity.
(default: 0, 0 = disabled, 1 = Mirostat, 2 = Mirostat 2.0)"""
mirostat_eta: Optional[float] = None
"""Influences how quickly the algorithm responds to feedback
from the generated text. A lower learning rate will result in
slower adjustments, while a higher learning rate will make
the algorithm more responsive. (Default: 0.1)"""
mirostat_tau: Optional[float] = None
"""Controls the balance between coherence and diversity
of the output. A lower value will result in more focused and
coherent text. (Default: 5.0)"""
num_ctx: Optional[int] = None
"""Sets the size of the context window used to generate the
next token. (Default: 2048) """
num_gpu: Optional[int] = None
"""The number of GPUs to use. On macOS it defaults to 1 to
enable metal support, 0 to disable."""
num_thread: Optional[int] = None
"""Sets the number of threads to use during computation.
By default, Ollama will detect this for optimal performance.
It is recommended to set this value to the number of physical
CPU cores your system has (as opposed to the logical number of cores)."""
repeat_last_n: Optional[int] = None
"""Sets how far back for the model to look back to prevent
repetition. (Default: 64, 0 = disabled, -1 = num_ctx)"""
repeat_penalty: Optional[float] = None
"""Sets how strongly to penalize repetitions. A higher value (e.g., 1.5)
will penalize repetitions more strongly, while a lower value (e.g., 0.9)
will be more lenient. (Default: 1.1)"""
temperature: Optional[float] = None
"""The temperature of the model. Increasing the temperature will
make the model answer more creatively. (Default: 0.8)"""
stop: Optional[List[str]] = None
"""Sets the stop tokens to use."""
tfs_z: Optional[float] = None
"""Tail free sampling is used to reduce the impact of less probable
tokens from the output. A higher value (e.g., 2.0) will reduce the
impact more, while a value of 1.0 disables this setting. (default: 1)"""
top_k: Optional[int] = None
"""Reduces the probability of generating nonsense. A higher value (e.g. 100)
will give more diverse answers, while a lower value (e.g. 10)
will be more conservative. (Default: 40)"""
top_p: Optional[float] = None
"""Works together with top-k. A higher value (e.g., 0.95) will lead
to more diverse text, while a lower value (e.g., 0.5) will
generate more focused and conservative text. (Default: 0.9)"""
model_config = ConfigDict(
extra="forbid",
)
@property
def _default_params(self) -> Dict[str, Any]:
"""Get the default parameters for calling Ollama."""
return {
"mirostat": self.mirostat,
"mirostat_eta": self.mirostat_eta,
"mirostat_tau": self.mirostat_tau,
"num_ctx": self.num_ctx,
"num_gpu": self.num_gpu,
"num_thread": self.num_thread,
"repeat_last_n": self.repeat_last_n,
"repeat_penalty": self.repeat_penalty,
"temperature": self.temperature,
"stop": self.stop,
"tfs_z": self.tfs_z,
"top_k": self.top_k,
"top_p": self.top_p,
}
@model_validator(mode="after")
def _set_clients(self) -> Self:
"""Set clients to use for ollama."""
client_kwargs = self.client_kwargs or {}
self._client = Client(host=self.base_url, **client_kwargs)
self._async_client = AsyncClient(host=self.base_url, **client_kwargs)
return self
[docs]
def embed_documents(self, texts: List[str]) -> List[List[float]]:
"""Embed search docs."""
embedded_docs = self._client.embed(
self.model, texts, options=self._default_params
)["embeddings"]
return embedded_docs
[docs]
def embed_query(self, text: str) -> List[float]:
"""Embed query text."""
return self.embed_documents([text])[0]
[docs]
async def aembed_documents(self, texts: List[str]) -> List[List[float]]:
"""Embed search docs."""
embedded_docs = (await self._async_client.embed(self.model, texts))[
"embeddings"
]
return embedded_docs
[docs]
async def aembed_query(self, text: str) -> List[float]:
"""Embed query text."""
return (await self.aembed_documents([text]))[0]
