[python][R-package] removed duplicated code from language wrappers (#2606)

* removed duplicated code from language wrappers

* removed check for resetting metric

R-package/R/aliases.R

@@ -18,15 +18,6 @@
             , "early_stopping"
             , "n_iter_no_change"
         )
-        , "metric" = c(
-            "metric"
-            , "metrics"
-            , "metric_types"
-        )
-        , "num_class" = c(
-            "num_class"
-            , "num_classes"
-        )
         , "num_iterations" = c(
             "num_iterations"
             , "num_iteration"

R-package/R/callback.R

@@ -34,21 +34,6 @@ cb.reset.parameters <- function(new_params) {
       stop("Env should have a ", sQuote("model"))
     }
 
-    # Some parameters are not allowed to be changed,
-    # since changing them would simply wreck some chaos
-    not_allowed <- c(
-      .PARAMETER_ALIASES()[["num_class"]]
-      , .PARAMETER_ALIASES()[["metric"]]
-      , .PARAMETER_ALIASES()[["boosting"]]
-    )
-    if (any(pnames %in% not_allowed)) {
-      stop(
-        "Parameters "
-        , paste0(pnames[pnames %in% not_allowed], collapse = ", ")
-        , " cannot be changed during boosting"
-      )
-    }
-
     # Store boosting rounds
     nrounds <<- env$end_iteration - env$begin_iteration + 1L
 

R-package/tests/testthat/test_parameters.R

@@ -50,8 +50,6 @@ test_that(".PARAMETER_ALIASES() returns a named list", {
   expect_true(is.character(names(param_aliases)))
   expect_true(is.character(param_aliases[["boosting"]]))
   expect_true(is.character(param_aliases[["early_stopping_round"]]))
-  expect_true(is.character(param_aliases[["metric"]]))
-  expect_true(is.character(param_aliases[["num_class"]]))
   expect_true(is.character(param_aliases[["num_iterations"]]))
 })
 

python-package/lightgbm/basic.py

@@ -2037,8 +2037,6 @@ class Booster(object):
         self : Booster
             Booster with new parameters.
         """
-        if any(metric_alias in params for metric_alias in _ConfigAliases.get("metric")):
-            self.__need_reload_eval_info = True
         params_str = param_dict_to_str(params)
         if params_str:
             _safe_call(_LIB.LGBM_BoosterResetParameter(

python-package/lightgbm/callback.py

@@ -130,8 +130,6 @@ def reset_parameter(**kwargs):
     def _callback(env):
         new_parameters = {}
         for key, value in kwargs.items():
-            if key in _ConfigAliases.get("num_class", "boosting", "metric"):
-                raise RuntimeError("Cannot reset {} during training".format(repr(key)))
             if isinstance(value, list):
                 if len(value) != env.end_iteration - env.begin_iteration:
                     raise ValueError("Length of list {} has to equal to 'num_boost_round'."