Still no o200k_base support

[Xan-Kun]

System Information (please complete the following information):

• OS & Version: all
• OS & Version: all
• ML.NET Version: all
• .NET Version: all

Describe the bug
No way to tokenize gpt-4o strings!

To Reproduce
Tokenize a string for gpt-4o

Expected behavior
The most recent models are supported.

[stephentoub]

a) Please be respectful.
b) Even the official openai/tiktoken repo only merged support for gpt-4o 3 days ago: openai/tiktoken@9d01e56. Integrated support will be coming here as well.
c) Tokenizer does support the new model, it's just not as integrated as for the other models because the vocab file and associated regex aren't baked in. I expect @tarekgh would be able to share a sample.

[tarekgh]

Here is the sample how to create the gpt-4o.

const string ENDOFTEXT = "<|endoftext|>";
const string ENDOFPROMPT = "<|endofprompt|>";
Dictionary<string, int> specialTokens = new() 
{ 
    { ENDOFTEXT,   199999 },
    { ENDOFPROMPT, 200018 }
};
string regexPattern = @"[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]*[\p{Ll}\p{Lm}\p{Lo}\p{M}]+(?i:'s|'t|'re|'ve|'m|'ll|'d)?|[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]+[\p{Ll}\p{Lm}\p{Lo}\p{M}]*(?i:'s|'t|'re|'ve|'m|'ll|'d)?|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n/]*|\s*[\r\n]+|\s+(?!\S)|\s+";
Regex regex = new Regex(regexPattern, RegexOptions.Compiled);
HttpClient httpClient = new HttpClient();
Tiktoken tiktoken= await Tiktoken.CreateAsync(await httpClient.GetStreamAsync(@"https://openaipublic.blob.core.windows.net/encodings/o200k_base.tiktoken"), specialTokens);
Tokenizer gpt4o = new Tokenizer(tiktoken, new TiktokenPreTokenizer(regex, specialTokens));

gpt4o.EncodeToIds("Hello, World!<|endoftext|>").ToList().ForEach(Console.WriteLine);

Note, this is using the library version:

    <PackageReference Include="Microsoft.ML.Tokenizers" Version="0.22.0-preview.24179.1" />

I didn't do deep testing as https://platform.openai.com/tokenizer didn't enable this new model.

[tarekgh]

CC @ericstj @luisquintanilla

[tarekgh]

This change is now published to the NuGet https://www.nuget.org/packages/Microsoft.ML.Tokenizers/0.22.0-preview.24271.1