LLamaSharp/LLama/LLamaInstructExecutor.cs

using LLama.Abstractions.Params;
using LLama.Native;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace LLama
{
    using llama_token = Int32;
    public class LLamaInstructExecutor : LLamaExecutorBase
    {
        bool _prompt_run = true;
        readonly IEnumerable<llama_token> _inp_pfx;
        readonly IEnumerable<llama_token> _inp_sfx;
        public LLamaInstructExecutor(LLamaModel model, string inputPrefix = "\n\n### Instruction:\n\n",
            string inputSuffix = "\n\n### Response:\n\n") : base(model)
        {
            _inp_pfx = _model.Tokenize(inputPrefix, true);
            _inp_sfx = _model.Tokenize(inputSuffix, false);
        }

        protected override bool GetLoopCondition(InferStateArgs args)
        {
            return args.RemainedTokens != 0 || _prompt_run;
        }
        protected override void PreprocessInputs(string text, InferStateArgs args)
        {
            if (_prompt_run)
            {
                // When running the first input (prompt) in inteactive mode, we should specially process it.
                text = " " + text;
                _embed_inps = _model.Tokenize(text, true).ToList();
            }
            else
            {
                if (!text.EndsWith("\n"))
                {
                    text += "\n";
                }
                _consumedTokensCount = _embed_inps.Count;
                _embed_inps.AddRange(_inp_pfx);

                var line_inp = _model.Tokenize(text, false);
                _embed_inps.AddRange(line_inp);

                _embed_inps.AddRange(_inp_sfx);

                args.RemainedTokens -= line_inp.Count();
            }
        }
        protected override bool PostProcess(SessionParams sessionParams, InferStateArgs args, out IEnumerable<string>? extraOutputs)
        {
            extraOutputs = null;
            if (_embed_inps.Count <= _consumedTokensCount)
            {
                if (args.Antiprompts is not null && args.Antiprompts.Count > 0)
                {
                    string last_output = "";
                    foreach (var id in _last_n_tokens)
                    {
                        last_output += Utils.PtrToString(NativeApi.llama_token_to_str(_model.NativeHandle, id), _model.Encoding);
                    }

                    foreach (var antiprompt in args.Antiprompts)
                    {
                        if (last_output.EndsWith(antiprompt))
                        {
                            args.WaitForInput = true;
                            return true;
                        }
                    }
                }

                if (_pastTokensCount > 0 && args.WaitForInput)
                {
                    extraOutputs = new string[] { "\n> " };
                    return true;
                }
            }

            if (_embeds.Count > 0 && _embeds.Last() == NativeApi.llama_token_eos())
            {
                args.WaitForInput = true;
            }

            if (args.RemainedTokens <= 0 && sessionParams.ResponseTokensCount != -1)
            {
                args.RemainedTokens = sessionParams.ResponseTokensCount;
                args.WaitForInput = true;
            }
            return false;
        }
        protected override void InferInternal(SessionParams sessionParams, InferStateArgs args)
        {
            if (_embeds.Count > 0)
            {
                _prompt_run = false;
                if (_pastTokensCount + _embeds.Count > _model.ContextSize)
                {
                    HandleRunOutOfContext(sessionParams.TokensToKeep);
                }

                TryReuseMathingPrefix();
                _pastTokensCount = _model.Eval(_embeds.ToArray(), _pastTokensCount);

                if (_embeds.Count > 0 && !string.IsNullOrEmpty(_pathSession))
                {
                    _session_tokens.AddRange(_embeds);
                    _n_session_consumed = _session_tokens.Count;
                }
            }

            _embeds.Clear();

            if (_embed_inps.Count <= _consumedTokensCount && !args.WaitForInput)
            {
                var temp = sessionParams.Temperature;
                var top_k = sessionParams.TopK <= 0 ? NativeApi.llama_n_vocab(_model.NativeHandle) : sessionParams.TopK;
                var top_p = sessionParams.TopK;
                var tfs_z = sessionParams.TfsZ;
                var typical_p = sessionParams.TypicalP;
                var repeat_last_n = sessionParams.RepeatLastTokensCount < 0 ? _model.ContextSize : sessionParams.RepeatLastTokensCount;
                var repeat_penalty = sessionParams.RepeatPenalty;
                var alpha_presence = sessionParams.PresencePenalty;
                var alpha_frequency = sessionParams.FrequencyPenalty;
                var mirostat = sessionParams.Mirostat;
                var mirostat_tau = sessionParams.MirostatTau;
                var mirostat_eta = sessionParams.MirostatEta;
                var penalize_nl = sessionParams.PenalizeNL;

                // optionally save the session on first sample (for faster prompt loading next time)
                if (!string.IsNullOrEmpty(_pathSession) && args.NeedToSaveSession)
                {
                    args.NeedToSaveSession = false;
                    SaveSessionFile(_pathSession);
                }

                var tokenDataArray = _model.ApplyPenalty(_last_n_tokens, sessionParams.LogitBias, repeat_last_n,
                    repeat_penalty, alpha_frequency, alpha_presence, penalize_nl);

                var id = _model.Sample(tokenDataArray, temp, mirostat, mirostat_tau, mirostat_eta, top_k, top_p,
                    tfs_z, typical_p);

                _last_n_tokens.Enqueue(id);

                _embeds.Add(id);

                args.RemainedTokens--;
                args.ReturnValue = true;
            }
            else
            {
                while (_embed_inps.Count > _consumedTokensCount)
                {
                    _embeds.Add(_embed_inps[_consumedTokensCount]);
                    _last_n_tokens.Enqueue(_embed_inps[_consumedTokensCount]);
                    _consumedTokensCount++;
                    if (_embeds.Count >= _model.Params.BatchSize)
                    {
                        break;
                    }
                }
            }
        }
    }
}