Error: Method not found: 'System.Threading.Tasks.Task`1<Ollama.GenerateEmbeddingResponse> Ollama.OllamaApiClient.GenerateEmbeddingAsync(

[mzeesam]

Describe the bug

I get the below error: Method not found: 'System.Threading.Tasks.Task`1 Ollama.OllamaApiClient.GenerateEmbeddingAsync(Ollama.GenerateEmbeddingRequest, System.Threading.CancellationToken)'.

When executing the following lines: var vectorCollection = await vectorDatabase.AddDocumentsFromAsync( embeddingModel, // Used to convert text to embeddings dimensions: 384, // Should be 1536 for TextEmbeddingV3SmallModel //dimensions: 384, //for all-MiniLM- 384 dimensions dataSource: DataSource.FromUrl("https://canonburyprimaryschool.co.uk/wp-content/uploads/2016/01/Joanne-K.-Rowling-Harry-Potter-Book-1-Harry-Potter-and-the-Philosophers-Stone-EnglishOnlineClub.com_.pdf"), collectionName: "harrypotter", // Can be omitted, use if you want to have multiple collections textSplitter: null, behavior: AddDocumentsToDatabaseBehavior.JustReturnCollectionIfCollectionIsAlreadyExists);

OR

var similarDocuments = await vectorCollection.GetSimilarDocuments(embeddingModel, question, amount: 5);

I am using version 0.14.1-dev60 in all the nuget packages. I installed Ollama on my PC and running on the default port: 11434

Below is the entire code:

using LangChain.Databases.Sqlite;
using LangChain.DocumentLoaders;
using LangChain.Providers.Ollama;
using LangChain.Extensions;
using Ollama;
using LangChain.Splitters.Text;

var provider = new OllamaProvider(options: new RequestOptions
{
    Stop = ["\n"],
    Temperature = 0.0f,
});
var embeddingModel = new OllamaEmbeddingModel(provider, id: "all-minilm");
//var embeddingModel = new OllamaEmbeddingModel(provider, id: "nomic-embed-text");
//var embeddingModel = new OllamaEmbeddingModel(provider, id: "mxbai-embed-large")
var llm = new OllamaChatModel(provider, id: "llama3");

Console.WriteLine($"Setting up vector DB...");
var vectorDatabase = new SqLiteVectorDatabase(dataSource: "vectors.db");

Console.WriteLine($"Loading, Chunking and Indexing data ...");

//Error here below:
var vectorCollection = await vectorDatabase.AddDocumentsFromAsync<PdfPigPdfLoader>(
    embeddingModel, // Used to convert text to embeddings
    dimensions: 384, // Should be 1536 for TextEmbeddingV3SmallModel
                      //dimensions: 384, //for all-MiniLM- 384 dimensions
    dataSource: DataSource.FromUrl("https://canonburyprimaryschool.co.uk/wp-content/uploads/2016/01/Joanne-K.-Rowling-Harry-Potter-Book-1-Harry-Potter-and-the-Philosophers-Stone-EnglishOnlineClub.com_.pdf"),
    collectionName: "harrypotter", // Can be omitted, use if you want to have multiple collections
    textSplitter: null,
    behavior: AddDocumentsToDatabaseBehavior.JustReturnCollectionIfCollectionIsAlreadyExists);

Console.WriteLine($"Data loading done.");
const string question = "What is Harry's Address?";
Console.WriteLine($"Question: {question}");

var similarDocuments = await vectorCollection.GetSimilarDocuments(embeddingModel, question, amount: 5); //Error here...
// Use similar documents and LLM to answer the question
var answer = await llm.GenerateAsync(
    $"""
     Use the following pieces of context to answer the question at the end.
     If the answer is not in context then just say that you don't know, don't try to make up an answer.
     Keep the answer as short as possible.

     {similarDocuments.AsString()}

     Question: {question}
     Helpful Answer:
     """).ConfigureAwait(false);

Console.ForegroundColor = ConsoleColor.Green;
Console.WriteLine($"LLM answer: {answer}");

Console.ForegroundColor = ConsoleColor.White;
//optionally write out the vectordb similar documents
Console.WriteLine("Similar Documents:");
foreach (var document in similarDocuments)
{
    Console.WriteLine(document);
}

Steps to reproduce the bug

1. Copy the code as expalined in article: https://medium.com/@johnkane24/a-completely-local-rag-net-langchain-sqlite-and-ollama-with-no-api-keys-required-d36c53652f00
2. Installed all nuget packages
3. Run

Expected behavior

No response

Screenshots

No response

NuGet package version

No response

Additional context

No response

[HavenDV]

Possibly related to recent changes in the Ollama client, I'll let you know when it's fixed

[mzeesam]

Alright, Thank you. Which versions of libraries/Ollama client can I use in the meantime?

[HavenDV]

I updated Ollama SDK dependency to latest, new version of LangChain should be available in 5-10 minutes.

[mzeesam]

Thank you sir. Well noted.

However, i am now getting error 404 as shown below:

Ollama is running well on localhost. Or Should I open a different issue?

Thanks.

[HavenDV]

I think it's because default url was changed. You can set custom url in OllamaProvider ctor("http://localhost:11434/api") or just wait for new NuGet

[mzeesam]

Awesome!!... Thanks a lot. The embeddings are created successfully.