Merge pull request #219 from TeamHG-Memex/lightgbm-fix

Fixed LightGBM explain_prediction

.travis.yml

@@ -11,23 +11,17 @@ matrix:
     - python: 2.7
       env: TOXENV=py27
     - python: 2.7
-      env:
-        - TOXENV=py27-extra
-        - LIGHTGBM=1
+      env: TOXENV=py27-extra
     - python: 3.5
       env: TOXENV=py35
     - python: 3.5
-      env:
-        - TOXENV=py35-extra
-        - LIGHTGBM=1
+      env: TOXENV=py35-extra
     - python: 3.5
       env: TOXENV=py35-nodeps
     - python: 3.6
       env: TOXENV=py36
     - python: 3.6
-      env:
-        - TOXENV=py36-extra
-        - LIGHTGBM=1
+      env: TOXENV=py36-extra
     - python: 3.5
       env: TOXENV=mypy
     - python: 3.5
@@ -41,11 +35,11 @@ addons:
             - libatlas-base-dev
             - liblapack-dev
             - gfortran
+            - cmake
 
 before_install:
     - sudo apt-get -qq update
     - if [[ "$TOXENV" != "py35-nodeps" ]]; then sudo apt-get install graphviz; fi
-    - if [[ "$LIGHTGBM" = 1 ]]; then bash _ci/install_lightgbm_linux.sh; export LIGHTGBM_CHECKOUT=LightGBM; fi
 
 install:
     - pip install -U pip tox codecov

_ci/runtests_extra.sh

@@ -1,9 +1,4 @@
 #!/usr/bin/env bash
-EXTRA_IGNORE=""
-if [ -z "${LIGHTGBM_CHECKOUT}" ]; then
-    EXTRA_IGNORE="--ignore eli5/lightgbm.py"
-fi
-
 py.test --doctest-modules \
         --ignore tests/test_lime.py \
         --ignore tests/test_formatters.py \
@@ -12,5 +7,5 @@ py.test --doctest-modules \
         --ignore tests/test_sklearn_explain_weights.py \
         --ignore tests/test_sklearn_vectorizers.py \
         --ignore tests/test_utils.py \
-        --ignore eli5/lightning.py ${EXTRA_IGNORE} \
+        --ignore eli5/lightning.py \
         --cov=eli5 --cov-report=html --cov-report=term "$@"

eli5/lightgbm.py

@@ -178,8 +178,12 @@ def walk(tree):
         left_value, left_count = walk(tree['left_child'])
         right_value, right_count = walk(tree['right_child'])
         count = left_count + right_count
-        tree['node_value'] = (left_value * left_count +
-                              right_value * right_count) / count
+        if tree['split_gain'] <= 0:
+            assert left_value == right_value
+            tree['node_value'] = left_value
+        else:
+            tree['node_value'] = (left_value * left_count +
+                                  right_value * right_count) / count
         return tree['node_value'], count
 
     for tree in tree_info:

tox.ini

@@ -1,12 +1,9 @@
 ; this is a tox config for running ELI5 tests
 ; under all supported Python interpreters.
 
-; To run LightGBM tests set LIGHTGBM_CHECKOUT
-; env variable to a path to LightGBM checkout folder, e.g.
-; LIGHTGBM_CHECKOUT=~/source/LightGBM tox -e py35-extra.
-;
-; LightGBM library itself should be already built, as described at
-; https://github.com/Microsoft/LightGBM/wiki/Installation-Guide
+; Building LighGBM may require additional system-level dependencies
+; (e.g. cmake); please consult with
+; https://github.com/Microsoft/LightGBM/tree/master/python-package#lightgbm-python-package.
 
 [tox]
 envlist = py27,py34,py35,py35-nodeps,mypy,py35-extra,py27-extra,py36,py36-extra
@@ -22,7 +19,6 @@ deps=
 
 
 [testenv]
-passenv = LIGHTGBM_CHECKOUT
 whitelist_externals = /bin/bash
 deps=
     {[base]deps}
@@ -52,13 +48,10 @@ basepython=python3.5
 deps=
     {[testenv]deps}
     xgboost
+    lightgbm
 
 commands=
     pip install -e .
-
-    ; install LighGBM Python wrapper
-    bash ./_ci/install_py_lightgbm.sh
-
     ; run tests for extra dependencies
     bash _ci/runtests_extra.sh {posargs: eli5 tests}