[docs] added MAP to list when eval_at is used (#1509)

docs/Parameters.rst

@@ -785,11 +785,11 @@ Metric Parameters
 
    -  set this to ``true`` to output metric result over training dataset
 
--  ``eval_at`` :raw-html:`<a id="eval_at" title="Permalink to this parameter" href="#eval_at">&#x1F517;&#xFE0E;</a>`, default = ``1,2,3,4,5``, type = multi-int, aliases: ``ndcg_eval_at``, ``ndcg_at``
+-  ``eval_at`` :raw-html:`<a id="eval_at" title="Permalink to this parameter" href="#eval_at">&#x1F517;&#xFE0E;</a>`, default = ``1,2,3,4,5``, type = multi-int, aliases: ``ndcg_eval_at``, ``ndcg_at``, ``map_eval_at``, ``map_at``
 
    -  used only with ``ndcg`` and ``map`` metrics
 
-   -  `NDCG <https://en.wikipedia.org/wiki/Discounted_cumulative_gain#Normalized_DCG>`__ evaluation positions, separated by ``,``
+   -  `NDCG <https://en.wikipedia.org/wiki/Discounted_cumulative_gain#Normalized_DCG>`__ and `MAP <https://makarandtapaswi.wordpress.com/2012/07/02/intuition-behind-average-precision-and-map/>`__ evaluation positions, separated by ``,``
 
 Network Parameters
 ------------------

include/LightGBM/config.h

@@ -695,9 +695,9 @@ public:
 
   // type = multi-int
   // default = 1,2,3,4,5
-  // alias = ndcg_eval_at, ndcg_at
+  // alias = ndcg_eval_at, ndcg_at, map_eval_at, map_at
   // desc = used only with ``ndcg`` and ``map`` metrics
-  // desc = `NDCG <https://en.wikipedia.org/wiki/Discounted_cumulative_gain#Normalized_DCG>`__ evaluation positions, separated by ``,``
+  // desc = `NDCG <https://en.wikipedia.org/wiki/Discounted_cumulative_gain#Normalized_DCG>`__ and `MAP <https://makarandtapaswi.wordpress.com/2012/07/02/intuition-behind-average-precision-and-map/>`__ evaluation positions, separated by ``,``
   std::vector<int> eval_at;
 
   #pragma endregion

src/io/config_auto.cpp

@@ -123,6 +123,8 @@ std::unordered_map<std::string, std::string> Config::alias_table({
   {"train_metric", "is_provide_training_metric"},
   {"ndcg_eval_at", "eval_at"},
   {"ndcg_at", "eval_at"},
+  {"map_eval_at", "eval_at"},
+  {"map_at", "eval_at"},
   {"num_machine", "num_machines"},
   {"local_port", "local_listen_port"},
   {"port", "local_listen_port"},