Files
llama.cpp/common/sampling.cpp
Daniel Bevenius 51fee29822 sampling : always populate logits for sampled probs
This commit updates common/sampler.cpp set_logits and
src/llama-sampling.cpp llama_sampler_sample to always populate the
logits field when backend sampled probabilities are available.

The motivation for this is that this ensure that CPU sampler always have
access to the logits values even when probabilites have been produced by
backend samplers.
2025-11-19 07:14:11 +01:00

673 lines
25 KiB
C++

#include "sampling.h"
#include "common.h"
#include "log.h"
#include <cmath>
#include <unordered_map>
#include <algorithm>
// the ring buffer works similarly to std::deque, but with a fixed capacity
// TODO: deduplicate with llama-impl.h
template<typename T>
struct ring_buffer {
ring_buffer(size_t cap) : capacity(cap), data(cap) {}
T & front() {
if (sz == 0) {
throw std::runtime_error("ring buffer is empty");
}
return data[first];
}
const T & front() const {
if (sz == 0) {
throw std::runtime_error("ring buffer is empty");
}
return data[first];
}
T & back() {
if (sz == 0) {
throw std::runtime_error("ring buffer is empty");
}
return data[pos];
}
const T & back() const {
if (sz == 0) {
throw std::runtime_error("ring buffer is empty");
}
return data[pos];
}
void push_back(const T & value) {
if (sz == capacity) {
// advance the start when buffer is full
first = (first + 1) % capacity;
} else {
sz++;
}
data[pos] = value;
pos = (pos + 1) % capacity;
}
T pop_front() {
if (sz == 0) {
throw std::runtime_error("ring buffer is empty");
}
T value = data[first];
first = (first + 1) % capacity;
sz--;
return value;
}
const T & rat(size_t i) const {
if (i >= sz) {
throw std::runtime_error("ring buffer: index out of bounds");
}
return data[(first + sz - i - 1) % capacity];
}
std::vector<T> to_vector() const {
std::vector<T> result;
result.reserve(sz);
for (size_t i = 0; i < sz; i++) {
result.push_back(data[(first + i) % capacity]);
}
return result;
}
void clear() {
// here only reset the status of the buffer
sz = 0;
first = 0;
pos = 0;
}
bool empty() const {
return sz == 0;
}
size_t size() const {
return sz;
}
size_t capacity = 0;
size_t sz = 0;
size_t first = 0;
size_t pos = 0;
std::vector<T> data;
};
struct common_sampler {
common_params_sampling params;
struct llama_sampler * grmr;
struct llama_sampler * chain;
ring_buffer<llama_token> prev;
std::vector<llama_token_data> cur;
llama_token_data_array cur_p;
void set_logits(struct llama_context * ctx, int idx) {
const float * sampled_probs = llama_get_backend_sampled_probs_ith (ctx, idx);
const float * sampled_logits = llama_get_backend_sampled_logits_ith (ctx, idx);
const llama_token * sampled_ids = llama_get_backend_sampled_token_ids_ith(ctx, idx);
const llama_model * model = llama_get_model(ctx);
const llama_vocab * vocab = llama_model_get_vocab(model);
const int n_vocab = llama_vocab_n_tokens(vocab);
// Use the member variable instead of allocating locally
cur.clear();
if (sampled_probs) {
const uint32_t sampled_probs_count = llama_get_backend_sampled_probs_count_ith(ctx, idx);
cur.reserve(sampled_probs_count);
for (uint32_t i = 0; i < sampled_probs_count; ++i) {
cur.emplace_back(llama_token_data{sampled_ids[i], sampled_logits[i], sampled_probs[i]});
}
} else if (sampled_logits) {
const uint32_t sampled_logits_count = llama_get_backend_sampled_logits_count_ith(ctx, idx);
cur.reserve(sampled_logits_count);
for (uint32_t i = 0; i < sampled_logits_count; i++) {
cur.emplace_back(llama_token_data{sampled_ids[i], sampled_logits[i], 0.0f});
}
} else {
const auto * logits = llama_get_logits_ith(ctx, idx);
GGML_ASSERT(logits != nullptr);
cur.reserve(n_vocab);
for (llama_token token_id = 0; token_id < n_vocab; token_id++) {
cur.emplace_back(llama_token_data{token_id, logits[token_id], 0.0f});
}
}
cur_p = { cur.data(), cur.size(), -1, false };
}
};
static bool sampler_enabled(const struct common_params_sampling & params, enum common_sampler_type type) {
return std::find(params.samplers.begin(), params.samplers.end(), type) != params.samplers.end();
}
std::string common_params_sampling::print() const {
char result[1024];
snprintf(result, sizeof(result),
"\trepeat_last_n = %d, repeat_penalty = %.3f, frequency_penalty = %.3f, presence_penalty = %.3f\n"
"\tdry_multiplier = %.3f, dry_base = %.3f, dry_allowed_length = %d, dry_penalty_last_n = %d\n"
"\ttop_k = %d, top_p = %.3f, min_p = %.3f, xtc_probability = %.3f, xtc_threshold = %.3f, typical_p = %.3f, top_n_sigma = %.3f, temp = %.3f\n"
"\tmirostat = %d, mirostat_lr = %.3f, mirostat_ent = %.3f",
penalty_last_n, penalty_repeat, penalty_freq, penalty_present,
dry_multiplier, dry_base, dry_allowed_length, dry_penalty_last_n,
top_k, top_p, min_p, xtc_probability, xtc_threshold, typ_p, top_n_sigma, temp,
mirostat, mirostat_eta, mirostat_tau);
return std::string(result);
}
struct common_sampler * common_sampler_init(const struct llama_model * model, const struct common_params_sampling & params) {
const llama_vocab * vocab = llama_model_get_vocab(model);
llama_sampler_chain_params lparams = llama_sampler_chain_default_params();
lparams.no_perf = params.no_perf;
struct llama_sampler * grmr;
if (params.grammar.compare(0, 11, "%llguidance") == 0) {
#ifdef LLAMA_USE_LLGUIDANCE
grmr = llama_sampler_init_llg(vocab, "lark", params.grammar.c_str());
#else
GGML_ABORT("llguidance (cmake -DLLAMA_LLGUIDANCE=ON) is not enabled");
#endif // LLAMA_USE_LLGUIDANCE
} else {
std::vector<std::string> trigger_patterns;
std::vector<std::string> patterns_anywhere;
std::vector<llama_token> trigger_tokens;
for (const auto & trigger : params.grammar_triggers) {
switch (trigger.type) {
case COMMON_GRAMMAR_TRIGGER_TYPE_WORD:
{
const auto & word = trigger.value;
patterns_anywhere.push_back(regex_escape(word));
break;
}
case COMMON_GRAMMAR_TRIGGER_TYPE_PATTERN:
{
patterns_anywhere.push_back(trigger.value);
break;
}
case COMMON_GRAMMAR_TRIGGER_TYPE_PATTERN_FULL:
{
trigger_patterns.push_back(trigger.value);
break;
}
case COMMON_GRAMMAR_TRIGGER_TYPE_TOKEN:
{
const auto token = trigger.token;
trigger_tokens.push_back(token);
break;
}
default:
GGML_ASSERT(false && "unknown trigger type");
}
}
if (!patterns_anywhere.empty()) {
trigger_patterns.push_back("^[\\s\\S]*?(" + string_join(patterns_anywhere, "|") + ")[\\s\\S]*");
}
std::vector<const char *> trigger_patterns_c;
trigger_patterns_c.reserve(trigger_patterns.size());
for (const auto & regex : trigger_patterns) {
trigger_patterns_c.push_back(regex.c_str());
}
grmr = params.grammar_lazy
? llama_sampler_init_grammar_lazy_patterns(vocab, params.grammar.c_str(), "root",
trigger_patterns_c.data(), trigger_patterns_c.size(),
trigger_tokens.data(), trigger_tokens.size())
: llama_sampler_init_grammar(vocab, params.grammar.c_str(), "root");
if (!grmr) {
return nullptr;
}
}
auto * result = new common_sampler {
/* .params = */ params,
/* .grmr = */ grmr,
/* .chain = */ llama_sampler_chain_init(lparams),
/* .prev = */ ring_buffer<llama_token>(std::max(32, params.n_prev)),
/* .cur = */ {},
/* .cur_p = */ {},
};
llama_sampler_chain_add(result->chain,
llama_sampler_init_logit_bias(
llama_vocab_n_tokens(vocab),
params.logit_bias.size(),
params.logit_bias.data()));
if (params.mirostat == 0) {
for (const auto & cnstr : params.samplers) {
switch (cnstr) {
case COMMON_SAMPLER_TYPE_DRY:
{
std::vector<const char *> c_breakers;
c_breakers.reserve(params.dry_sequence_breakers.size());
for (const auto & str : params.dry_sequence_breakers) {
c_breakers.push_back(str.c_str());
}
llama_sampler_chain_add(result->chain, llama_sampler_init_dry (vocab, llama_model_n_ctx_train(model), params.dry_multiplier, params.dry_base, params.dry_allowed_length, params.dry_penalty_last_n, c_breakers.data(), c_breakers.size()));
}
break;
case COMMON_SAMPLER_TYPE_TOP_K:
llama_sampler_chain_add(result->chain, llama_sampler_init_top_k (params.top_k));
break;
case COMMON_SAMPLER_TYPE_TOP_P:
llama_sampler_chain_add(result->chain, llama_sampler_init_top_p (params.top_p, params.min_keep));
break;
case COMMON_SAMPLER_TYPE_TOP_N_SIGMA:
llama_sampler_chain_add(result->chain, llama_sampler_init_top_n_sigma (params.top_n_sigma));
break;
case COMMON_SAMPLER_TYPE_MIN_P:
llama_sampler_chain_add(result->chain, llama_sampler_init_min_p (params.min_p, params.min_keep));
break;
case COMMON_SAMPLER_TYPE_XTC:
llama_sampler_chain_add(result->chain, llama_sampler_init_xtc (params.xtc_probability, params.xtc_threshold, params.min_keep, params.seed));
break;
case COMMON_SAMPLER_TYPE_TYPICAL_P:
llama_sampler_chain_add(result->chain, llama_sampler_init_typical (params.typ_p, params.min_keep));
break;
case COMMON_SAMPLER_TYPE_TEMPERATURE:
llama_sampler_chain_add(result->chain, llama_sampler_init_temp_ext (params.temp, params.dynatemp_range, params.dynatemp_exponent));
break;
case COMMON_SAMPLER_TYPE_INFILL:
llama_sampler_chain_add(result->chain, llama_sampler_init_infill (vocab));
break;
case COMMON_SAMPLER_TYPE_PENALTIES:
llama_sampler_chain_add(result->chain, llama_sampler_init_penalties (params.penalty_last_n, params.penalty_repeat, params.penalty_freq, params.penalty_present));
break;
default:
GGML_ASSERT(false && "unknown sampler type");
}
}
llama_sampler_chain_add(result->chain, llama_sampler_init_dist(params.seed));
} else if (params.mirostat == 1) {
llama_sampler_chain_add(result->chain, llama_sampler_init_temp(params.temp));
llama_sampler_chain_add(result->chain, llama_sampler_init_mirostat(llama_vocab_n_tokens(vocab), params.seed, params.mirostat_tau, params.mirostat_eta, 100));
} else if (params.mirostat == 2) {
llama_sampler_chain_add(result->chain, llama_sampler_init_temp(params.temp));
llama_sampler_chain_add(result->chain, llama_sampler_init_mirostat_v2(params.seed, params.mirostat_tau, params.mirostat_eta));
} else {
GGML_ASSERT(false && "unknown mirostat version");
}
return result;
}
struct llama_sampler * common_sampler_backend_init(const struct llama_model * model, const struct common_params_sampling & params) {
const llama_vocab * vocab = llama_model_get_vocab(model);
llama_sampler_chain_params chain_params = llama_sampler_chain_default_params();
chain_params.no_perf = params.no_perf;
struct llama_sampler * chain = llama_sampler_chain_init(chain_params);
if (!params.backend_sampling) {
return chain; // return empty chain
}
const bool enable_temp = params.temp > 0.0f && sampler_enabled(params, COMMON_SAMPLER_TYPE_TEMPERATURE);
const bool enable_top_k = params.top_k > 0 && sampler_enabled(params, COMMON_SAMPLER_TYPE_TOP_K);
const bool enable_dist = params.backend_dist;
if (!params.logit_bias.empty()) {
llama_sampler_chain_add(chain, llama_sampler_backend_init_logit_bias(
llama_vocab_n_tokens(vocab),
params.logit_bias.size(),
params.logit_bias.data()));
}
if (enable_temp) {
llama_sampler_chain_add(chain, llama_sampler_backend_init_temp(params.temp));
}
if (enable_top_k) {
llama_sampler_chain_add(chain, llama_sampler_backend_init_top_k(params.top_k));
}
if (enable_dist) {
llama_sampler_chain_add(chain, llama_sampler_backend_init_dist(params.seed));
}
return chain;
}
void common_sampler_free(struct common_sampler * gsmpl) {
if (gsmpl) {
llama_sampler_free(gsmpl->grmr);
llama_sampler_free(gsmpl->chain);
delete gsmpl;
}
}
void common_sampler_accept(struct common_sampler * gsmpl, llama_token token, bool accept_grammar) {
if (accept_grammar) {
llama_sampler_accept(gsmpl->grmr, token);
}
llama_sampler_accept(gsmpl->chain, token);
gsmpl->prev.push_back(token);
}
void common_sampler_reset(struct common_sampler * gsmpl) {
llama_sampler_reset(gsmpl->grmr);
llama_sampler_reset(gsmpl->chain);
}
struct common_sampler * common_sampler_clone(common_sampler * gsmpl) {
return new common_sampler {
/* .params = */ gsmpl->params,
/* .grmr = */ llama_sampler_clone(gsmpl->grmr),
/* .chain = */ llama_sampler_clone(gsmpl->chain),
/* .prev = */ gsmpl->prev,
/* .cur = */ gsmpl->cur,
/* .cur_p = */ gsmpl->cur_p,
};
}
void common_perf_print(const struct llama_context * ctx, const struct common_sampler * gsmpl) {
// TODO: measure grammar performance
if (gsmpl) {
llama_perf_sampler_print(gsmpl->chain);
}
if (ctx) {
llama_perf_context_print(ctx);
llama_memory_breakdown_print(ctx);
}
}
llama_token common_sampler_sample(struct common_sampler * gsmpl, struct llama_context * ctx, int idx, bool grammar_first) {
// Check if a backend sampler has already sampled a token in which case we
// return that token id directly.
{
const llama_token id = llama_get_backend_sampled_token_ith(ctx, idx);
if (id != LLAMA_TOKEN_NULL) {
LOG_DBG("%s: Backend sampler selected token: '%d'. Will not run any CPU samplers\n", __func__, id);
return id;
}
}
gsmpl->set_logits(ctx, idx);
auto & grmr = gsmpl->grmr;
auto & chain = gsmpl->chain;
auto & cur_p = gsmpl->cur_p; // initialized by set_logits
if (grammar_first) {
llama_sampler_apply(grmr, &cur_p);
}
llama_sampler_apply(chain, &cur_p);
GGML_ASSERT(cur_p.selected != -1 && "no selected token during sampling - check your sampling configuration");
const llama_token id = cur_p.data[cur_p.selected].id;
if (grammar_first) {
return id;
}
// check if it the sampled token fits the grammar
{
llama_token_data single_token_data = { id, 1.0f, 0.0f };
llama_token_data_array single_token_data_array = { &single_token_data, 1, -1, false };
llama_sampler_apply(grmr, &single_token_data_array);
const bool is_valid = single_token_data_array.data[0].logit != -INFINITY;
if (is_valid) {
return id;
}
}
// resampling:
// if the token is not valid, sample again, but first apply the grammar sampler and then the sampling chain
gsmpl->set_logits(ctx, idx);
llama_sampler_apply(grmr, &cur_p);
llama_sampler_apply(chain, &cur_p);
GGML_ASSERT(cur_p.selected != -1 && "no selected token during re-sampling - check your sampling configuration");
return cur_p.data[cur_p.selected].id;
}
std::vector<llama_token> common_sampler_sample_and_accept_n(struct common_sampler * gsmpl, struct llama_context * ctx, const std::vector<int> & idxs, const llama_tokens & draft, bool grammar_first) {
GGML_ASSERT(idxs.size() == draft.size() + 1 && "idxs.size() must be draft.size() + 1");
std::vector<llama_token> result;
result.reserve(idxs.size());
size_t i = 0;
for (; i < draft.size(); i++) {
const llama_token id = common_sampler_sample(gsmpl, ctx, idxs[i], grammar_first);
common_sampler_accept(gsmpl, id, true);
result.push_back(id);
if (draft[i] != id) {
break;
}
}
if (i == draft.size()) {
const llama_token id = common_sampler_sample(gsmpl, ctx, idxs[i], grammar_first);
common_sampler_accept(gsmpl, id, true);
result.push_back(id);
}
return result;
}
std::vector<llama_token> common_sampler_sample_and_accept_n(struct common_sampler * gsmpl, struct llama_context * ctx, const llama_tokens & draft, bool grammar_first) {
std::vector<int> idxs(draft.size() + 1);
for (size_t i = 0; i < idxs.size(); ++i) {
idxs[i] = i;
}
return common_sampler_sample_and_accept_n(gsmpl, ctx, idxs, draft, grammar_first);
}
uint32_t common_sampler_get_seed(const struct common_sampler * gsmpl) {
return llama_sampler_get_seed(gsmpl->chain);
}
// helpers
llama_token_data_array * common_sampler_get_candidates(struct common_sampler * gsmpl, bool do_sort) {
auto * res = &gsmpl->cur_p;
if (do_sort && !res->sorted) {
// remember the selected token before sorting
const llama_token id = res->data[res->selected].id;
std::sort(res->data, res->data + res->size, [](const llama_token_data & a, const llama_token_data & b) {
return a.p > b.p;
});
// restore the selected token after sorting
for (size_t i = 0; i < res->size; ++i) {
if (res->data[i].id == id) {
res->selected = i;
break;
}
}
res->sorted = true;
}
return res;
}
llama_token common_sampler_last(const struct common_sampler * gsmpl) {
return gsmpl->prev.rat(0);
}
std::string common_sampler_print(const struct common_sampler * gsmpl) {
std::string result = "logits ";
for (int i = 0; i < llama_sampler_chain_n(gsmpl->chain); i++) {
const auto * smpl = llama_sampler_chain_get(gsmpl->chain, i);
result += std::string("-> ") + llama_sampler_name(smpl) + " ";
}
return result;
}
std::string common_sampler_prev_str(common_sampler * gsmpl, llama_context * ctx_main, int n) {
n = std::min(n, (int) gsmpl->prev.size());
if (n <= 0) {
return "";
}
std::string result;
result.reserve(8*n); // 8 is the average length of a token [citation needed], TODO: compute this from the vocab
for (int i = n - 1; i >= 0; i--) {
const llama_token id = gsmpl->prev.rat(i);
GGML_ASSERT(id != LLAMA_TOKEN_NULL && "null token in the sampling history - should not happen");
result += common_token_to_piece(ctx_main, id);
}
return result;
}
char common_sampler_type_to_chr(enum common_sampler_type cnstr) {
switch (cnstr) {
case COMMON_SAMPLER_TYPE_DRY: return 'd';
case COMMON_SAMPLER_TYPE_TOP_K: return 'k';
case COMMON_SAMPLER_TYPE_TYPICAL_P: return 'y';
case COMMON_SAMPLER_TYPE_TOP_P: return 'p';
case COMMON_SAMPLER_TYPE_TOP_N_SIGMA: return 's';
case COMMON_SAMPLER_TYPE_MIN_P: return 'm';
case COMMON_SAMPLER_TYPE_TEMPERATURE: return 't';
case COMMON_SAMPLER_TYPE_XTC: return 'x';
case COMMON_SAMPLER_TYPE_INFILL: return 'i';
case COMMON_SAMPLER_TYPE_PENALTIES: return 'e';
default : return '?';
}
}
std::string common_sampler_type_to_str(enum common_sampler_type cnstr) {
switch (cnstr) {
case COMMON_SAMPLER_TYPE_DRY: return "dry";
case COMMON_SAMPLER_TYPE_TOP_K: return "top_k";
case COMMON_SAMPLER_TYPE_TYPICAL_P: return "typ_p";
case COMMON_SAMPLER_TYPE_TOP_P: return "top_p";
case COMMON_SAMPLER_TYPE_TOP_N_SIGMA: return "top_n_sigma";
case COMMON_SAMPLER_TYPE_MIN_P: return "min_p";
case COMMON_SAMPLER_TYPE_TEMPERATURE: return "temperature";
case COMMON_SAMPLER_TYPE_XTC: return "xtc";
case COMMON_SAMPLER_TYPE_INFILL: return "infill";
case COMMON_SAMPLER_TYPE_PENALTIES: return "penalties";
default : return "";
}
}
std::vector<common_sampler_type> common_sampler_types_from_names(const std::vector<std::string> & names, bool allow_alt_names) {
std::unordered_map<std::string, common_sampler_type> sampler_canonical_name_map {
{ "dry", COMMON_SAMPLER_TYPE_DRY },
{ "top_k", COMMON_SAMPLER_TYPE_TOP_K },
{ "top_p", COMMON_SAMPLER_TYPE_TOP_P },
{ "top_n_sigma", COMMON_SAMPLER_TYPE_TOP_N_SIGMA },
{ "typ_p", COMMON_SAMPLER_TYPE_TYPICAL_P },
{ "min_p", COMMON_SAMPLER_TYPE_MIN_P },
{ "temperature", COMMON_SAMPLER_TYPE_TEMPERATURE },
{ "xtc", COMMON_SAMPLER_TYPE_XTC },
{ "infill", COMMON_SAMPLER_TYPE_INFILL },
{ "penalties", COMMON_SAMPLER_TYPE_PENALTIES },
};
// since samplers names are written multiple ways
// make it ready for both system names and input names
std::unordered_map<std::string, common_sampler_type> sampler_alt_name_map {
{ "top-k", COMMON_SAMPLER_TYPE_TOP_K },
{ "top-p", COMMON_SAMPLER_TYPE_TOP_P },
{ "top-n-sigma", COMMON_SAMPLER_TYPE_TOP_N_SIGMA },
{ "nucleus", COMMON_SAMPLER_TYPE_TOP_P },
{ "typical-p", COMMON_SAMPLER_TYPE_TYPICAL_P },
{ "typical", COMMON_SAMPLER_TYPE_TYPICAL_P },
{ "typ-p", COMMON_SAMPLER_TYPE_TYPICAL_P },
{ "typ", COMMON_SAMPLER_TYPE_TYPICAL_P },
{ "min-p", COMMON_SAMPLER_TYPE_MIN_P },
{ "temp", COMMON_SAMPLER_TYPE_TEMPERATURE },
};
std::vector<common_sampler_type> samplers;
samplers.reserve(names.size());
for (const auto & name : names) {
auto sampler = sampler_canonical_name_map.find(name);
if (sampler != sampler_canonical_name_map.end()) {
samplers.push_back(sampler->second);
continue;
}
if (allow_alt_names) {
sampler = sampler_alt_name_map.find(name);
if (sampler != sampler_alt_name_map.end()) {
samplers.push_back(sampler->second);
continue;
}
}
LOG_WRN("%s: unable to match sampler by name '%s'\n", __func__, name.c_str());
}
return samplers;
}
std::vector<common_sampler_type> common_sampler_types_from_chars(const std::string & chars) {
std::unordered_map<char, common_sampler_type> sampler_name_map = {
{ common_sampler_type_to_chr(COMMON_SAMPLER_TYPE_DRY), COMMON_SAMPLER_TYPE_DRY },
{ common_sampler_type_to_chr(COMMON_SAMPLER_TYPE_TOP_K), COMMON_SAMPLER_TYPE_TOP_K },
{ common_sampler_type_to_chr(COMMON_SAMPLER_TYPE_TYPICAL_P), COMMON_SAMPLER_TYPE_TYPICAL_P },
{ common_sampler_type_to_chr(COMMON_SAMPLER_TYPE_TOP_P), COMMON_SAMPLER_TYPE_TOP_P },
{ common_sampler_type_to_chr(COMMON_SAMPLER_TYPE_TOP_N_SIGMA), COMMON_SAMPLER_TYPE_TOP_N_SIGMA },
{ common_sampler_type_to_chr(COMMON_SAMPLER_TYPE_MIN_P), COMMON_SAMPLER_TYPE_MIN_P },
{ common_sampler_type_to_chr(COMMON_SAMPLER_TYPE_TEMPERATURE), COMMON_SAMPLER_TYPE_TEMPERATURE },
{ common_sampler_type_to_chr(COMMON_SAMPLER_TYPE_XTC), COMMON_SAMPLER_TYPE_XTC },
{ common_sampler_type_to_chr(COMMON_SAMPLER_TYPE_INFILL), COMMON_SAMPLER_TYPE_INFILL },
{ common_sampler_type_to_chr(COMMON_SAMPLER_TYPE_PENALTIES), COMMON_SAMPLER_TYPE_PENALTIES },
};
std::vector<common_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);
} else {
LOG_WRN("%s: unable to match sampler by char '%c'\n", __func__, c);
}
}
return samplers;
}