mirror of
https://github.com/ggerganov/llama.cpp.git
synced 2024-11-15 07:19:53 +00:00
b0f27361f3
* sampling : avoid expensive softmax during greedy sampling ggml-ci * speculative : fix default RNG seed + set sparams.n_probs * Update tests/test-sampling.cpp Co-authored-by: slaren <slarengh@gmail.com> * sampling : add clarifying comment [no ci] --------- Co-authored-by: slaren <slarengh@gmail.com>
459 lines
15 KiB
C++
459 lines
15 KiB
C++
#include "sampling.h"
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#include "common.h"
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#include <cmath>
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#include <unordered_map>
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// the ring buffer works similarly to std::deque, but with a fixed capacity
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// TODO: deduplicate with llama-impl.h
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template<typename T>
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struct ring_buffer {
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ring_buffer(size_t cap) : capacity(cap), data(cap) {}
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T & front() {
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if (sz == 0) {
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throw std::runtime_error("ring buffer is empty");
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}
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return data[first];
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}
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const T & front() const {
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if (sz == 0) {
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throw std::runtime_error("ring buffer is empty");
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}
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return data[first];
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}
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T & back() {
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if (sz == 0) {
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throw std::runtime_error("ring buffer is empty");
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}
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return data[pos];
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}
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const T & back() const {
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if (sz == 0) {
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throw std::runtime_error("ring buffer is empty");
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}
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return data[pos];
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}
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void push_back(const T & value) {
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if (sz == capacity) {
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// advance the start when buffer is full
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first = (first + 1) % capacity;
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} else {
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sz++;
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}
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data[pos] = value;
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pos = (pos + 1) % capacity;
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}
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T pop_front() {
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if (sz == 0) {
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throw std::runtime_error("ring buffer is empty");
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}
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T value = data[first];
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first = (first + 1) % capacity;
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sz--;
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return value;
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}
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const T & rat(size_t i) const {
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if (i >= sz) {
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throw std::runtime_error("ring buffer: index out of bounds");
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}
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return data[(first + sz - i - 1) % capacity];
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}
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std::vector<T> to_vector() const {
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std::vector<T> result;
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result.reserve(sz);
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for (size_t i = 0; i < sz; i++) {
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result.push_back(data[(first + i) % capacity]);
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}
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return result;
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}
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void clear() {
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// here only reset the status of the buffer
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sz = 0;
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first = 0;
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pos = 0;
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}
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bool empty() const {
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return sz == 0;
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}
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size_t size() const {
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return sz;
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}
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size_t capacity = 0;
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size_t sz = 0;
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size_t first = 0;
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size_t pos = 0;
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std::vector<T> data;
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};
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struct gpt_sampler {
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gpt_sampler_params params;
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struct llama_sampler * grmr;
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struct llama_sampler * chain;
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ring_buffer<llama_token> prev;
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std::vector<llama_token_data> cur;
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llama_token_data_array cur_p;
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void set_logits(struct llama_context * ctx, int idx) {
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const auto * logits = llama_get_logits_ith(ctx, idx);
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const int n_vocab = llama_n_vocab(llama_get_model(ctx));
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cur.resize(n_vocab);
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for (llama_token token_id = 0; token_id < n_vocab; token_id++) {
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cur[token_id] = llama_token_data{token_id, logits[token_id], 0.0f};
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}
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cur_p = { cur.data(), cur.size(), -1, false };
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}
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};
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std::string gpt_sampler_params::print() const {
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char result[1024];
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snprintf(result, sizeof(result),
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"\trepeat_last_n = %d, repeat_penalty = %.3f, frequency_penalty = %.3f, presence_penalty = %.3f\n"
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"\ttop_k = %d, tfs_z = %.3f, top_p = %.3f, min_p = %.3f, typical_p = %.3f, temp = %.3f\n"
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"\tmirostat = %d, mirostat_lr = %.3f, mirostat_ent = %.3f",
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penalty_last_n, penalty_repeat, penalty_freq, penalty_present,
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top_k, tfs_z, top_p, min_p, typ_p, temp,
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mirostat, mirostat_eta, mirostat_tau);
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return std::string(result);
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}
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struct gpt_sampler * gpt_sampler_init(const struct llama_model * model, const struct gpt_sampler_params & params) {
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llama_sampler_chain_params lparams = llama_sampler_chain_default_params();
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lparams.no_perf = params.no_perf;
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auto * result = new gpt_sampler {
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/* .params = */ params,
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/* .grmr = */ llama_sampler_init_grammar(model, params.grammar.c_str(), "root"),
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/* .chain = */ llama_sampler_chain_init(lparams),
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/* .prev = */ ring_buffer<llama_token>(std::max(32, params.n_prev)),
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/* .cur = */ {},
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/* .cur_p = */ {},
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};
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llama_sampler_chain_add(result->chain,
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llama_sampler_init_logit_bias(
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llama_n_vocab(model),
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params.logit_bias.size(),
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params.logit_bias.data()));
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llama_sampler_chain_add(result->chain,
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llama_sampler_init_penalties(
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llama_n_vocab (model),
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llama_token_eos(model),
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llama_token_nl (model),
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params.penalty_last_n,
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params.penalty_repeat,
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params.penalty_freq,
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params.penalty_present,
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params.penalize_nl,
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params.ignore_eos));
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if (params.temp > 0.0f) {
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if (params.mirostat == 0) {
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for (const auto & cnstr : params.samplers) {
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switch (cnstr) {
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case GPT_SAMPLER_TYPE_TOP_K:
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llama_sampler_chain_add(result->chain, llama_sampler_init_top_k (params.top_k));
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break;
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case GPT_SAMPLER_TYPE_TOP_P:
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llama_sampler_chain_add(result->chain, llama_sampler_init_top_p (params.top_p, params.min_keep));
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break;
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case GPT_SAMPLER_TYPE_MIN_P:
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llama_sampler_chain_add(result->chain, llama_sampler_init_min_p (params.min_p, params.min_keep));
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break;
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case GPT_SAMPLER_TYPE_TFS_Z:
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llama_sampler_chain_add(result->chain, llama_sampler_init_tail_free(params.tfs_z, params.min_keep));
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break;
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case GPT_SAMPLER_TYPE_TYPICAL_P:
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llama_sampler_chain_add(result->chain, llama_sampler_init_typical (params.typ_p, params.min_keep));
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break;
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case GPT_SAMPLER_TYPE_TEMPERATURE:
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llama_sampler_chain_add(result->chain, llama_sampler_init_temp_ext (params.temp, params.dynatemp_range, params.dynatemp_exponent));
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break;
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default:
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GGML_ASSERT(false && "unknown sampler type");
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}
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}
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llama_sampler_chain_add(result->chain, llama_sampler_init_softmax());
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llama_sampler_chain_add(result->chain, llama_sampler_init_dist(params.seed));
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} else if (params.mirostat == 1) {
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llama_sampler_chain_add(result->chain, llama_sampler_init_temp(params.temp));
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llama_sampler_chain_add(result->chain, llama_sampler_init_mirostat(llama_n_vocab(model), params.seed, params.mirostat_tau, params.mirostat_eta, 100));
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} else if (params.mirostat == 2) {
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llama_sampler_chain_add(result->chain, llama_sampler_init_temp(params.temp));
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llama_sampler_chain_add(result->chain, llama_sampler_init_mirostat_v2(params.seed, params.mirostat_tau, params.mirostat_eta));
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} else {
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GGML_ASSERT(false && "unknown mirostat version");
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}
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} else {
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if (params.n_probs > 0) {
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// some use cases require to sample greedily, but still obtain the probabilities of the top tokens
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// ref: https://github.com/ggerganov/llama.cpp/pull/9605
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//
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// the following will not produce exactly the same probs as applyging softmax to the full vocabulary, but
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// it is much faster, since we avoid sorting all tokens and should give a good approximation
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llama_sampler_chain_add(result->chain, llama_sampler_init_top_k(params.n_probs));
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llama_sampler_chain_add(result->chain, llama_sampler_init_softmax());
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}
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llama_sampler_chain_add(result->chain, llama_sampler_init_greedy());
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}
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return result;
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}
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void gpt_sampler_free(struct gpt_sampler * gsmpl) {
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if (gsmpl) {
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llama_sampler_free(gsmpl->grmr);
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llama_sampler_free(gsmpl->chain);
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delete gsmpl;
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}
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}
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void gpt_sampler_accept(struct gpt_sampler * gsmpl, llama_token token, bool accept_grammar) {
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if (accept_grammar) {
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llama_sampler_accept(gsmpl->grmr, token);
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}
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llama_sampler_accept(gsmpl->chain, token);
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gsmpl->prev.push_back(token);
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}
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void gpt_sampler_reset(struct gpt_sampler * gsmpl) {
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llama_sampler_reset(gsmpl->grmr);
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llama_sampler_reset(gsmpl->chain);
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}
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struct gpt_sampler * gpt_sampler_clone(gpt_sampler * gsmpl) {
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return new gpt_sampler {
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/* .params = */ gsmpl->params,
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/* .grmr = */ llama_sampler_clone(gsmpl->grmr),
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/* .chain = */ llama_sampler_clone(gsmpl->chain),
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/* .prev = */ gsmpl->prev,
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/* .cur = */ gsmpl->cur,
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/* .cur_p = */ gsmpl->cur_p,
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};
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}
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void gpt_perf_print(const struct llama_context * ctx, const struct gpt_sampler * gsmpl) {
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// TODO: measure grammar performance
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if (gsmpl) {
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llama_perf_sampler_print(gsmpl->chain);
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}
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if (ctx) {
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llama_perf_context_print(ctx);
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}
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}
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llama_token gpt_sampler_sample(struct gpt_sampler * gsmpl, struct llama_context * ctx, int idx, bool grammar_first) {
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gsmpl->set_logits(ctx, idx);
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auto & grmr = gsmpl->grmr;
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auto & chain = gsmpl->chain;
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auto & cur_p = gsmpl->cur_p; // initialized by set_logits
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if (grammar_first) {
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llama_sampler_apply(grmr, &cur_p);
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}
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llama_sampler_apply(chain, &cur_p);
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GGML_ASSERT(cur_p.selected != -1 && "no selected token during sampling - check your sampling configuration");
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const llama_token id = cur_p.data[cur_p.selected].id;
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if (grammar_first) {
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return id;
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}
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// check if it the sampled token fits the grammar
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{
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llama_token_data single_token_data = { id, 1.0f, 0.0f };
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llama_token_data_array single_token_data_array = { &single_token_data, 1, -1, false };
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llama_sampler_apply(grmr, &single_token_data_array);
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const bool is_valid = single_token_data_array.data[0].logit != -INFINITY;
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if (is_valid) {
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return id;
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}
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}
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// resampling:
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// if the token is not valid, sample again, but first apply the grammar sampler and then the sampling chain
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gsmpl->set_logits(ctx, idx);
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llama_sampler_apply(grmr, &cur_p);
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llama_sampler_apply(chain, &cur_p);
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GGML_ASSERT(cur_p.selected != -1 && "no selected token during re-sampling - check your sampling configuration");
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return cur_p.data[cur_p.selected].id;
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}
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uint32_t gpt_sampler_get_seed(const struct gpt_sampler * gsmpl) {
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return llama_sampler_get_seed(gsmpl->chain);
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}
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// helpers
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llama_token_data_array * gpt_sampler_get_candidates(struct gpt_sampler * gsmpl) {
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return &gsmpl->cur_p;
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}
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llama_token gpt_sampler_last(const struct gpt_sampler * gsmpl) {
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return gsmpl->prev.rat(0);
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}
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std::string gpt_sampler_print(const struct gpt_sampler * gsmpl) {
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std::string result = "logits ";
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for (int i = 0; i < llama_sampler_chain_n(gsmpl->chain); i++) {
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const auto * smpl = llama_sampler_chain_get(gsmpl->chain, i);
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result += std::string("-> ") + llama_sampler_name(smpl) + " ";
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}
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return result;
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}
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std::string gpt_sampler_prev_str(gpt_sampler * gsmpl, llama_context * ctx_main, int n) {
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n = std::min(n, (int) gsmpl->prev.size());
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if (n <= 0) {
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return "";
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}
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std::string result;
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result.reserve(8*n); // 8 is the average length of a token [citation needed], TODO: compute this from the vocab
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for (int i = n - 1; i >= 0; i--) {
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const llama_token id = gsmpl->prev.rat(i);
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GGML_ASSERT(id != LLAMA_TOKEN_NULL && "null token in the sampling history - should not happen");
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result += llama_token_to_piece(ctx_main, id);
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}
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return result;
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}
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char gpt_sampler_type_to_chr(enum gpt_sampler_type cnstr) {
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switch (cnstr) {
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case GPT_SAMPLER_TYPE_TOP_K: return 'k';
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case GPT_SAMPLER_TYPE_TFS_Z: return 'f';
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case GPT_SAMPLER_TYPE_TYPICAL_P: return 'y';
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case GPT_SAMPLER_TYPE_TOP_P: return 'p';
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case GPT_SAMPLER_TYPE_MIN_P: return 'm';
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case GPT_SAMPLER_TYPE_TEMPERATURE: return 't';
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default : return '?';
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}
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}
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std::string gpt_sampler_type_to_str(enum gpt_sampler_type cnstr) {
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switch (cnstr) {
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case GPT_SAMPLER_TYPE_TOP_K: return "top_k";
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case GPT_SAMPLER_TYPE_TFS_Z: return "tfs_z";
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case GPT_SAMPLER_TYPE_TYPICAL_P: return "typ_p";
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case GPT_SAMPLER_TYPE_TOP_P: return "top_p";
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case GPT_SAMPLER_TYPE_MIN_P: return "min_p";
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case GPT_SAMPLER_TYPE_TEMPERATURE: return "temperature";
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default : return "";
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}
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}
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std::vector<gpt_sampler_type> gpt_sampler_types_from_names(const std::vector<std::string> & names, bool allow_alt_names) {
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std::unordered_map<std::string, gpt_sampler_type> sampler_canonical_name_map {
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{ "top_k", GPT_SAMPLER_TYPE_TOP_K },
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{ "top_p", GPT_SAMPLER_TYPE_TOP_P },
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{ "typ_p", GPT_SAMPLER_TYPE_TYPICAL_P },
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{ "min_p", GPT_SAMPLER_TYPE_MIN_P },
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{ "tfs_z", GPT_SAMPLER_TYPE_TFS_Z },
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{ "temperature", GPT_SAMPLER_TYPE_TEMPERATURE },
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};
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// since samplers names are written multiple ways
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// make it ready for both system names and input names
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std::unordered_map<std::string, gpt_sampler_type> sampler_alt_name_map {
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{ "top-k", GPT_SAMPLER_TYPE_TOP_K },
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{ "top-p", GPT_SAMPLER_TYPE_TOP_P },
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{ "nucleus", GPT_SAMPLER_TYPE_TOP_P },
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{ "typical-p", GPT_SAMPLER_TYPE_TYPICAL_P },
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{ "typical", GPT_SAMPLER_TYPE_TYPICAL_P },
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{ "typ-p", GPT_SAMPLER_TYPE_TYPICAL_P },
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{ "typ", GPT_SAMPLER_TYPE_TYPICAL_P },
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{ "min-p", GPT_SAMPLER_TYPE_MIN_P },
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{ "tfs-z", GPT_SAMPLER_TYPE_TFS_Z },
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{ "tfs", GPT_SAMPLER_TYPE_TFS_Z },
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{ "temp", GPT_SAMPLER_TYPE_TEMPERATURE },
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};
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std::vector<gpt_sampler_type> samplers;
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samplers.reserve(names.size());
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for (const auto & name : names) {
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auto sampler = sampler_canonical_name_map.find(name);
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if (sampler != sampler_canonical_name_map.end()) {
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samplers.push_back(sampler->second);
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} else {
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if (allow_alt_names) {
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sampler = sampler_alt_name_map.find(name);
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if (sampler != sampler_alt_name_map.end()) {
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samplers.push_back(sampler->second);
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}
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}
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}
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}
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return samplers;
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}
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std::vector<gpt_sampler_type> gpt_sampler_types_from_chars(const std::string & chars) {
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std::unordered_map<char, gpt_sampler_type> sampler_name_map = {
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{ gpt_sampler_type_to_chr(GPT_SAMPLER_TYPE_TOP_K), GPT_SAMPLER_TYPE_TOP_K },
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{ gpt_sampler_type_to_chr(GPT_SAMPLER_TYPE_TFS_Z), GPT_SAMPLER_TYPE_TFS_Z },
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{ gpt_sampler_type_to_chr(GPT_SAMPLER_TYPE_TYPICAL_P), GPT_SAMPLER_TYPE_TYPICAL_P },
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{ gpt_sampler_type_to_chr(GPT_SAMPLER_TYPE_TOP_P), GPT_SAMPLER_TYPE_TOP_P },
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{ gpt_sampler_type_to_chr(GPT_SAMPLER_TYPE_MIN_P), GPT_SAMPLER_TYPE_MIN_P },
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{ gpt_sampler_type_to_chr(GPT_SAMPLER_TYPE_TEMPERATURE), GPT_SAMPLER_TYPE_TEMPERATURE }
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};
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std::vector<gpt_sampler_type> samplers;
|
|
samplers.reserve(chars.size());
|
|
|
|
for (const auto & c : chars) {
|
|
const auto sampler = sampler_name_map.find(c);
|
|
if (sampler != sampler_name_map.end()) {
|
|
samplers.push_back(sampler->second);
|
|
}
|
|
}
|
|
|
|
return samplers;
|
|
}
|