common : relax sampler name matching (ggml-org#23744)

* common : relax sampler name matching

Currently, in some cases, the alternative names for samplers (like
`top-k` and `min-p` instead of the canonical `top_k` and `min_p`) are
not always recognized by the `common_sampler_types_from_names` function
in `common/sampling.cpp`.

This PR changes the signature of this function to remove the `bool
allow_alt_names` flag, and removes all occurences of the flag from call
sites. Therefore, the function will now always match all known names.

I also changed the logic of the function to unconditionally check the
provided sampler names against both the canonical and alternative names,
and to be case-insensitive.

This fixes an issue I was seeing wherein samplers specified in the
`llama-server` UI were not recognized as valid when the alternative
names were used.

* add more alt names

* cont. fix

* cast to unsigned char for correctness

* common : unify sampler name mapping

* annotate canonical vs. alt sampler name mappings per @CISC

* Update common/sampling.cpp

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

* common : auto-generate sampler name aliases per @ngxson

* use merged map for matching

* use `.merge` instead of iterating

* nit: simplify comment

* nit: use insert everywhere, not index assignment

---------

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

Author: ddh0

common/arg.cpp

@@ -1615,7 +1615,7 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
         string_format("samplers that will be used for generation in the order, separated by \';\'\n(default: %s)", sampler_type_names.c_str()),
         [](common_params & params, const std::string & value) {
             const auto sampler_names = string_split<std::string>(value, ';');
-            params.sampling.samplers = common_sampler_types_from_names(sampler_names, true);
+            params.sampling.samplers = common_sampler_types_from_names(sampler_names);
             params.sampling.user_sampling_config |= common_params_sampling_config::COMMON_PARAMS_SAMPLING_CONFIG_SAMPLERS;
         }
     ).set_sampling());

common/common.cpp

@@ -1148,7 +1148,7 @@ static void common_init_sampler_from_model(
         if (llama_model_meta_val_str(model, llama_model_meta_key_str(LLAMA_MODEL_META_KEY_SAMPLING_SEQUENCE), buf, sizeof(buf)) > 0) {
             const std::vector<std::string> sampler_names = string_split<std::string>(std::string(buf), ';');
             if (!sampler_names.empty()) {
-                sparams.samplers = common_sampler_types_from_names(sampler_names, true);
+                sparams.samplers = common_sampler_types_from_names(sampler_names);
             }
         }
     }

common/sampling.cpp

@@ -769,54 +769,63 @@ std::string common_sampler_type_to_str(enum common_sampler_type cnstr) {
     }
 }
 
-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 },
-        { "adaptive_p",  COMMON_SAMPLER_TYPE_ADAPTIVE_P },
-    };
-
-    // 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 },
-        { "adaptive-p",  COMMON_SAMPLER_TYPE_ADAPTIVE_P },
-    };
+std::vector<common_sampler_type> common_sampler_types_from_names(const std::vector<std::string> & names) {
+    // sampler names can be written multiple ways; generate aliases from canonical names
+    static const auto sampler_name_map = []{
+        // canonical sampler name mapping
+        std::unordered_map<std::string, common_sampler_type> 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   },
+            { "adaptive_p",  COMMON_SAMPLER_TYPE_ADAPTIVE_P  }
+        };
+        std::unordered_map<std::string, common_sampler_type> alias_name_map;
+        for (const auto & entry : canonical_name_map) {
+            const std::string & canonical = entry.first;
+            if (canonical.find('_') == std::string::npos) {
+                continue;
+            }
+            // kebab-case: "top-k", "min-p", etc.
+            {
+                std::string kebab_case = canonical;
+                std::replace(kebab_case.begin(), kebab_case.end(), '_', '-');
+                alias_name_map.insert({kebab_case, entry.second});
+            }
+            // no dash: "topk", "minp", etc.
+            {
+                std::string no_dash = canonical;
+                no_dash.erase(std::remove(no_dash.begin(), no_dash.end(), '_'), no_dash.end());
+                alias_name_map.insert({no_dash, entry.second});
+            }
+        }
+        // misc. aliases
+        alias_name_map.insert({"nucleus", COMMON_SAMPLER_TYPE_TOP_P});
+        alias_name_map.insert({"temp",    COMMON_SAMPLER_TYPE_TEMPERATURE});
+        alias_name_map.insert({"typ",     COMMON_SAMPLER_TYPE_TYPICAL_P});
+        // include aliases + canonical names in the complete mapping
+        alias_name_map.merge(canonical_name_map);
+        return alias_name_map;
+    }();
 
     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()) {
+        std::string name_lower = name;
+        std::transform(name_lower.begin(), name_lower.end(), name_lower.begin(), ::tolower);
+        auto sampler = sampler_name_map.find(name_lower);
+        if (sampler != sampler_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());
+        LOG_WRN("%s: unable to match sampler by name '%s'\n", __func__, name_lower.c_str());
     }
 
     return samplers;

common/sampling.h

@@ -109,7 +109,7 @@ std::string common_sampler_prev_str(common_sampler * gsmpl, llama_context * ctx,
 char        common_sampler_type_to_chr(enum common_sampler_type cnstr);
 std::string common_sampler_type_to_str(enum common_sampler_type cnstr);
 
-std::vector<enum common_sampler_type> common_sampler_types_from_names(const std::vector<std::string> & names, bool allow_alt_names);
+std::vector<enum common_sampler_type> common_sampler_types_from_names(const std::vector<std::string> & names);
 std::vector<enum common_sampler_type> common_sampler_types_from_chars(const std::string & chars);
 
 llama_sampler * llama_sampler_init_llg(const llama_vocab * vocab,

tools/server/server-task.cpp

@@ -605,7 +605,7 @@ task_params server_task::params_from_json_cmpl(
         const auto samplers = data.find("samplers");
         if (samplers != data.end()) {
             if (samplers->is_array()) {
-                params.sampling.samplers = common_sampler_types_from_names(*samplers, false);
+                params.sampling.samplers = common_sampler_types_from_names(*samplers);
             } else if (samplers->is_string()){
                 params.sampling.samplers = common_sampler_types_from_chars(samplers->get<std::string>());
             }