llama : add adaptive-p sampler (#17927)

* initial commit for branch

* simplify constants

* add params to `struct common_params_sampling`, add reference to PR

* explicitly clamp `min_target` and `max_target` to `[0.0, 1.0]`

* add args, rename `queue_size` -> `window_size`

* improved comments

* minor

* remove old unused code from algorithm

* minor

* add power law case to `common_sampler_init`, add sampler name mappings

* clarify behaviour when `window_size = 0`

* add missing enums

* remove `target_range` param, make `target == 1` no-op, cleanup code

* oops, straggler

* add missing parameters in `server-task.cpp`

* copy from author

ref:
https://gist.github.com/MrJackSpade/9be99c7efbba7b95a41377e123b7b069

* remove old debug log, style nit

* fix compiler warning, add commented-out logging per token

* re-write + change parameters + simplify

* oops forgot args.cpp

* fix leftover `window_size`

* add missing values to `common_params_sampling::print()`

* with logging

* does this fix it?

* no, but does this?

* update default decay

* optimize

* fix bad merge

my git skills are lacking

* silence `missing initializer for member`

* update default decay to 0.9

* fix logging

* format (double)

* add power law to the new `samplers` vector

* log sampler init values

* improve logging messages in llama_sampler_power_law

* remove extraneous logging

* simplify target computation

last commit with debug logging!

* remove debug logging, explicitly clamp params at init

* add `use_power_law` flag + logic, minor cleanup

* update `power-law` -> `adaptive-p`

* fix cold start EMA

- `ctx->weighted_sum` is now initialized and reset to `target / (1.0f -
clamped_decay)`
- `ctx->total_weight` is now initialized and reset to `1.0f / (1.0f -
clamped_decay)`

this fixes a "cold start" problem with the moving average

* update `SHARPNESS` constant to `10.0f`

* minor style fixes

no functional changes

* minor style fixes cont.

* update `llama_sampler_adaptive_p_i` for backend sampling (ref: #17004)

* separate into `apply` + `accept` functions

* `pending_token_idx`: switch from `llama_token` to `int32`

functionally identical (`llama.h` has `typedef int32_t llama_token;`),
but its more correct now

* don't transform logits <= -1e9f

* fix masking in backend top-p, min-p

* address review comments

* typo in comments `RND` -> `RNG`

* add docs

* add recommended values in completion docs

* address PR feedback

* remove trailing whitespace (for CI `editorconfig`)

* add to adaptive-p to `common_sampler_types_from_chars`
This commit is contained in:
ddh0
2026-01-15 11:16:29 -06:00
committed by GitHub
parent a04c2b06a3
commit 13f1e4a9ca
9 changed files with 297 additions and 52 deletions
+28 -25
View File
@@ -119,6 +119,7 @@ enum common_sampler_type {
COMMON_SAMPLER_TYPE_INFILL = 9,
COMMON_SAMPLER_TYPE_PENALTIES = 10,
COMMON_SAMPLER_TYPE_TOP_N_SIGMA = 11,
COMMON_SAMPLER_TYPE_ADAPTIVE_P = 12,
};
// dimensionality reduction methods, used by cvector-generator
@@ -166,32 +167,34 @@ enum common_params_sampling_config : uint64_t {
struct common_params_sampling {
uint32_t seed = LLAMA_DEFAULT_SEED; // the seed used to initialize llama_sampler
int32_t n_prev = 64; // number of previous tokens to remember
int32_t n_probs = 0; // if greater than 0, output the probabilities of top n_probs tokens.
int32_t min_keep = 0; // 0 = disabled, otherwise samplers should return at least min_keep tokens
int32_t top_k = 40; // <= 0 to use vocab size
float top_p = 0.95f; // 1.0 = disabled
float min_p = 0.05f; // 0.0 = disabled
float xtc_probability = 0.00f; // 0.0 = disabled
float xtc_threshold = 0.10f; // > 0.5 disables XTC
float typ_p = 1.00f; // typical_p, 1.0 = disabled
float temp = 0.80f; // <= 0.0 to sample greedily, 0.0 to not output probabilities
float dynatemp_range = 0.00f; // 0.0 = disabled
float dynatemp_exponent = 1.00f; // controls how entropy maps to temperature in dynamic temperature sampler
int32_t penalty_last_n = 64; // last n tokens to penalize (0 = disable penalty, -1 = context size)
float penalty_repeat = 1.00f; // 1.0 = disabled
float penalty_freq = 0.00f; // 0.0 = disabled
float penalty_present = 0.00f; // 0.0 = disabled
float dry_multiplier = 0.0f; // 0.0 = disabled; DRY repetition penalty for tokens extending repetition:
float dry_base = 1.75f; // 0.0 = disabled; multiplier * base ^ (length of sequence before token - allowed length)
int32_t dry_allowed_length = 2; // tokens extending repetitions beyond this receive penalty
int32_t dry_penalty_last_n = -1; // how many tokens to scan for repetitions (0 = disable penalty, -1 = context size)
int32_t mirostat = 0; // 0 = disabled, 1 = mirostat, 2 = mirostat 2.0
float top_n_sigma = -1.00f;// -1.0 = disabled
float mirostat_tau = 5.00f; // target entropy
float mirostat_eta = 0.10f; // learning rate
int32_t n_prev = 64; // number of previous tokens to remember
int32_t n_probs = 0; // if greater than 0, output the probabilities of top n_probs tokens.
int32_t min_keep = 0; // 0 = disabled, otherwise samplers should return at least min_keep tokens
int32_t top_k = 40; // <= 0 to use vocab size
float top_p = 0.95f; // 1.0 = disabled
float min_p = 0.05f; // 0.0 = disabled
float xtc_probability = 0.00f; // 0.0 = disabled
float xtc_threshold = 0.10f; // > 0.5 disables XTC
float typ_p = 1.00f; // typical_p, 1.0 = disabled
float temp = 0.80f; // <= 0.0 to sample greedily, 0.0 to not output probabilities
float dynatemp_range = 0.00f; // 0.0 = disabled
float dynatemp_exponent = 1.00f; // controls how entropy maps to temperature in dynamic temperature sampler
int32_t penalty_last_n = 64; // last n tokens to penalize (0 = disable penalty, -1 = context size)
float penalty_repeat = 1.00f; // 1.0 = disabled
float penalty_freq = 0.00f; // 0.0 = disabled
float penalty_present = 0.00f; // 0.0 = disabled
float dry_multiplier = 0.0f; // 0.0 = disabled; DRY repetition penalty for tokens extending repetition:
float dry_base = 1.75f; // 0.0 = disabled; multiplier * base ^ (length of sequence before token - allowed length)
int32_t dry_allowed_length = 2; // tokens extending repetitions beyond this receive penalty
int32_t dry_penalty_last_n = -1; // how many tokens to scan for repetitions (0 = disable penalty, -1 = context size)
float adaptive_target = -1.0f; // select tokens near this probability (valid range 0.0 to 1.0; negative = disabled)
float adaptive_decay = 0.90f; // EMA decay for adaptation; history ≈ 1/(1-decay) tokens (0.0 - 0.99)
int32_t mirostat = 0; // 0 = disabled, 1 = mirostat, 2 = mirostat 2.0
float top_n_sigma = -1.00f; // -1.0 = disabled
float mirostat_tau = 5.00f; // target entropy
float mirostat_eta = 0.10f; // learning rate
bool ignore_eos = false;
bool no_perf = false; // disable performance metrics
bool no_perf = false; // disable performance metrics
bool timing_per_token = false;
uint64_t user_sampling_config = 0; // bitfield to track user-specified samplers