[docs] update latest benchmark results (#2887)

* Update Experiments.rst

* Update docs/Experiments.rst

* Update Experiments.rst

* Update Experiments.rst

* fix  extra -> exact and some grammar
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

docs/Experiments.rst

@@ -6,6 +6,13 @@ Comparison Experiment
 
 For the detailed experiment scripts and output logs, please refer to this `repo`_.
 
+History
+^^^^^^^
+
+08 Mar, 2020: update according to the latest master branch (`1b97eaf <https://github.com/dmlc/xgboost/commit/1b97eaf7a74315bfa2c132d59f937a35408bcfd1>`__ for XGBoost, `bcad692 <https://github.com/microsoft/LightGBM/commit/bcad692e263e0317cab11032dd017c78f9e58e5f>`__ for LightGBM). (``xgboost_exact`` is not updated for it is too slow.)
+
+27 Feb, 2017: first version.
+
 Data
 ^^^^
 
@@ -28,12 +35,12 @@ We used 5 datasets to conduct our comparison experiments. Details of data are li
 Environment
 ^^^^^^^^^^^
 
-We ran all experiments on a single Linux server with the following specifications:
+We ran all experiments on a single Linux server (Azure ND24s) with the following specifications:
 
 +------------------+-----------------+---------------------+
 | OS               | CPU             | Memory              |
 +==================+=================+=====================+
-| Ubuntu 14.04 LTS | 2 \* E5-2670 v3 | DDR4 2133Mhz, 256GB |
+| Ubuntu 16.04 LTS | 2 \* E5-2690 v4 | 448GB               |
 +------------------+-----------------+---------------------+
 
 Baseline
@@ -96,23 +103,24 @@ Result
 Speed
 '''''
 
-We compared speed using only the training task without any test or metric output. We didn't count the time for IO.
+We compared speed using only the training task without any test or metric output. We didn't count the time for IO. 
+For the ranking tasks, since XGBoost and LightGBM implement different ranking objective functions, we used ``regression`` objective for speed benchmark, for the fair comparison.
 
 The following table is the comparison of time cost:
 
-+-----------+-----------+---------------+------------------+
-| Data      | xgboost   | xgboost\_hist | LightGBM         |
-+===========+===========+===============+==================+
-| Higgs     | 3794.34 s | 551.898 s     | **238.505513 s** |
-+-----------+-----------+---------------+------------------+
-| Yahoo LTR | 674.322 s | 265.302 s     | **150.18644 s**  |
-+-----------+-----------+---------------+------------------+
-| MS LTR    | 1251.27 s | 385.201 s     | **215.320316 s** |
-+-----------+-----------+---------------+------------------+
-| Expo      | 1607.35 s | 588.253 s     | **138.504179 s** |
-+-----------+-----------+---------------+------------------+
-| Allstate  | 2867.22 s | 1355.71 s     | **348.084475 s** |
-+-----------+-----------+---------------+------------------+
++-----------+-----------+---------------+---------------+
+| Data      | xgboost   | xgboost\_hist | LightGBM      |
++===========+===========+===============+===============+
+| Higgs     | 3794.34 s | 165.575 s     | **130.094 s** |
++-----------+-----------+---------------+---------------+
+| Yahoo LTR | 674.322 s | 131.462 s     | **76.229 s**  |
++-----------+-----------+---------------+---------------+
+| MS LTR    | 1251.27 s | 98.386 s      | **70.417 s**  |
++-----------+-----------+---------------+---------------+
+| Expo      | 1607.35 s | 137.65 s      | **62.607 s**  |
++-----------+-----------+---------------+---------------+
+| Allstate  | 2867.22 s | 315.256 s     | **148.231 s** |
++-----------+-----------+---------------+---------------+
 
 LightGBM ran faster than xgboost on all experiment data sets.
 
@@ -124,27 +132,27 @@ We computed all accuracy metrics only on the test data set.
 +-----------+-----------------+----------+-------------------+--------------+
 | Data      | Metric          | xgboost  | xgboost\_hist     | LightGBM     |
 +===========+=================+==========+===================+==============+
-| Higgs     | AUC             | 0.839593 | **0.845605**      | 0.845154     |
+| Higgs     | AUC             | 0.839593 | 0.845314          | **0.845724** |
 +-----------+-----------------+----------+-------------------+--------------+
-| Yahoo LTR | NDCG\ :sub:`1`  | 0.719748 | 0.720223          | **0.732466** |
+| Yahoo LTR | NDCG\ :sub:`1`  | 0.719748 | 0.720049          | **0.732981** |
 |           +-----------------+----------+-------------------+--------------+
-|           | NDCG\ :sub:`3`  | 0.717813 | 0.721519          | **0.738048** |
+|           | NDCG\ :sub:`3`  | 0.717813 | 0.722573          | **0.735689** |
 |           +-----------------+----------+-------------------+--------------+
-|           | NDCG\ :sub:`5`  | 0.737849 | 0.739904          | **0.756548** |
+|           | NDCG\ :sub:`5`  | 0.737849 | 0.740899          | **0.75352**  |
 |           +-----------------+----------+-------------------+--------------+
-|           | NDCG\ :sub:`10` | 0.78089  | 0.783013          | **0.796818** |
+|           | NDCG\ :sub:`10` | 0.78089  | 0.782957          | **0.793498** |
 +-----------+-----------------+----------+-------------------+--------------+
-| MS LTR    | NDCG\ :sub:`1`  | 0.483956 | 0.488649          | **0.524255** |
+| MS LTR    | NDCG\ :sub:`1`  | 0.483956 | 0.485115          | **0.517767** |
 |           +-----------------+----------+-------------------+--------------+
-|           | NDCG\ :sub:`3`  | 0.467951 | 0.473184          | **0.505327** |
+|           | NDCG\ :sub:`3`  | 0.467951 | 0.47313           | **0.501063** |
 |           +-----------------+----------+-------------------+--------------+
-|           | NDCG\ :sub:`5`  | 0.472476 | 0.477438          | **0.510007** |
+|           | NDCG\ :sub:`5`  | 0.472476 | 0.476375          | **0.504648** |
 |           +-----------------+----------+-------------------+--------------+
-|           | NDCG\ :sub:`10` | 0.492429 | 0.496967          | **0.527371** |
+|           | NDCG\ :sub:`10` | 0.492429 | 0.496553          | **0.524252** |
 +-----------+-----------------+----------+-------------------+--------------+
-| Expo      | AUC             | 0.756713 | **0.777777**      | 0.777543     |
+| Expo      | AUC             | 0.756713 | 0.776224          | **0.776935** |
 +-----------+-----------------+----------+-------------------+--------------+
-| Allstate  | AUC             | 0.607201 | 0.609042          | **0.609167** |
+| Allstate  | AUC             | 0.607201 | **0.609465**      |  0.609072    |
 +-----------+-----------------+----------+-------------------+--------------+
 
 Memory Consumption
@@ -153,23 +161,28 @@ Memory Consumption
 We monitored RES while running training task. And we set ``two_round=true`` (this will increase data-loading time and
 reduce peak memory usage but not affect training speed or accuracy) in LightGBM to reduce peak memory usage.
 
-+-----------+---------+---------------+-------------+
-| Data      | xgboost | xgboost\_hist | LightGBM    |
-+===========+=========+===============+=============+
-| Higgs     | 4.853GB | 3.784GB       | **0.868GB** |
-+-----------+---------+---------------+-------------+
-| Yahoo LTR | 1.907GB | 1.468GB       | **0.831GB** |
-+-----------+---------+---------------+-------------+
-| MS LTR    | 5.469GB | 3.654GB       | **0.886GB** |
-+-----------+---------+---------------+-------------+
-| Expo      | 1.553GB | 1.393GB       | **0.543GB** |
-+-----------+---------+---------------+-------------+
-| Allstate  | 6.237GB | 4.990GB       | **1.027GB** |
-+-----------+---------+---------------+-------------+
++-----------+---------+---------------+--------------------+--------------------+
+| Data      | xgboost | xgboost\_hist | LightGBM (col-wise)|LightGBM (row-wise) |
++===========+=========+===============+====================+====================+
+| Higgs     | 4.853GB | 7.335GB       | **0.897GB**        |     1.401GB        |
++-----------+---------+---------------+--------------------+--------------------+
+| Yahoo LTR | 1.907GB | 4.023GB       | **1.741GB**        |     2.161GB        |
++-----------+---------+---------------+--------------------+--------------------+
+| MS LTR    | 5.469GB | 7.491GB       | **0.940GB**        |     1.296GB        |
++-----------+---------+---------------+--------------------+--------------------+
+| Expo      | 1.553GB | 2.606GB       | **0.555GB**        |     0.711GB        |
++-----------+---------+---------------+--------------------+--------------------+
+| Allstate  | 6.237GB | 12.090GB      | **1.116GB**        |     1.755GB        |
++-----------+---------+---------------+--------------------+--------------------+
 
 Parallel Experiment
 -------------------
 
+History
+^^^^^^^
+
+27 Feb, 2017: first version.
+
 Data
 ^^^^