[WIP] Make our estimators compatible with scikit-learn

0001-Relax-init-parameter-type-checks.patch

@@ -0,0 +1,46 @@
+From 48a6dd8f0e7ff52d116b0c01e36dac4504547781 Mon Sep 17 00:00:00 2001
+From: Timo Kaufmann <timokau@zoho.com>
+Date: Thu, 16 Jul 2020 16:57:14 +0200
+Subject: [PATCH] Relax init parameter type checks
+
+We now allow any "type" (uninitialized classes) and all numeric numpy
+types. See https://github.com/scikit-learn/scikit-learn/issues/17756 for
+a discussion.
+---
+ sklearn/utils/estimator_checks.py | 20 ++++++++++++++------
+ 1 file changed, 14 insertions(+), 6 deletions(-)
+
+diff --git a/sklearn/utils/estimator_checks.py b/sklearn/utils/estimator_checks.py
+index 30c668237..ed3c40d67 100644
+--- a/sklearn/utils/estimator_checks.py
++++ b/sklearn/utils/estimator_checks.py
+@@ -2529,12 +2529,20 @@ def check_parameters_default_constructible(name, Estimator):
+             assert init_param.default != init_param.empty, (
+                 "parameter %s for %s has no default value"
+                 % (init_param.name, type(estimator).__name__))
+-            if type(init_param.default) is type:
+-                assert init_param.default in [np.float64, np.int64]
+-            else:
+-                assert (type(init_param.default) in
+-                        [str, int, float, bool, tuple, type(None),
+-                         np.float64, types.FunctionType, joblib.Memory])
++            allowed_types = {
++                str,
++                int,
++                float,
++                bool,
++                tuple,
++                type(None),
++                type,
++                types.FunctionType,
++                joblib.Memory,
++            }
++            # Any numpy numeric such as np.int32.
++            allowed_types.update(np.core.numerictypes.allTypes.values())
++            assert type(init_param.default) in allowed_types
+             if init_param.name not in params.keys():
+                 # deprecated parameter, not in get_params
+                 assert init_param.default is None
+-- 
+2.28.0
+

csrank/choicefunction/__init__.py

@@ -8,14 +8,16 @@
 from .pairwise_choice import PairwiseSVMChoiceFunction
 from .ranknet_choice import RankNetChoiceFunction
 
-__all__ = [
-    "AllPositive",
-    "CmpNetChoiceFunction",
-    "FATEChoiceFunction",
-    "FATELinearChoiceFunction",
-    "FETAChoiceFunction",
-    "FETALinearChoiceFunction",
-    "GeneralizedLinearModel",
-    "PairwiseSVMChoiceFunction",
-    "RankNetChoiceFunction",
+algorithms = [
+    AllPositive,
+    CmpNetChoiceFunction,
+    FATEChoiceFunction,
+    FATELinearChoiceFunction,
+    FETAChoiceFunction,
+    FETALinearChoiceFunction,
+    GeneralizedLinearModel,
+    PairwiseSVMChoiceFunction,
+    RankNetChoiceFunction,
 ]
+
+__all__ = [algo.__name__ for algo in algorithms]

csrank/dataset_reader/objectranking/util.py

@@ -35,7 +35,7 @@ def generate_pairwise_instances(features):
 
 def generate_complete_pairwise_dataset(X, Y):
     """
-        Generates the pairiwse preference data from the given rankings.The ranking amongst the objects in a query set
+        Generates the pairwise preference data from the given rankings.The ranking amongst the objects in a query set
         :math:`Q = \\{x_1, x_2, x_3\\}` is represented by :math:`\\pi = (2,1,3)`, such that :math:`\\pi(2)=1` is the position of the :math:`x_2`.
         One can extract the following *pairwise preferences* :math:`x_2 \\succ x_1, x_2 \\succ x_3 and x_1 \\succ x_3`.
         This function generates pairwise preferences which can be used to learn different :class:`ObjectRanker` as:

csrank/discretechoice/__init__.py

@@ -13,19 +13,21 @@
 from .pairwise_discrete_choice import PairwiseSVMDiscreteChoiceFunction
 from .ranknet_discrete_choice import RankNetDiscreteChoiceFunction
 
-__all__ = [
-    "RandomBaselineDC",
-    "CmpNetDiscreteChoiceFunction",
-    "FATEDiscreteChoiceFunction",
-    "FATELinearDiscreteChoiceFunction",
-    "FETADiscreteChoiceFunction",
-    "FETALinearDiscreteChoiceFunction",
-    "GeneralizedNestedLogitModel",
-    "MixedLogitModel",
-    "ModelSelector",
-    "MultinomialLogitModel",
-    "NestedLogitModel",
-    "PairedCombinatorialLogit",
-    "PairwiseSVMDiscreteChoiceFunction",
-    "RankNetDiscreteChoiceFunction",
+algorithms = [
+    RandomBaselineDC,
+    CmpNetDiscreteChoiceFunction,
+    FATEDiscreteChoiceFunction,
+    FATELinearDiscreteChoiceFunction,
+    FETADiscreteChoiceFunction,
+    FETALinearDiscreteChoiceFunction,
+    GeneralizedNestedLogitModel,
+    MixedLogitModel,
+    ModelSelector,
+    MultinomialLogitModel,
+    NestedLogitModel,
+    PairedCombinatorialLogit,
+    PairwiseSVMDiscreteChoiceFunction,
+    RankNetDiscreteChoiceFunction,
 ]
+
+__all__ = [algo.__name__ for algo in algorithms]

csrank/objectranking/__init__.py

@@ -9,15 +9,17 @@
 from .rank_net import RankNet
 from .rank_svm import RankSVM
 
-__all__ = [
-    "CmpNet",
-    "ExpectedRankRegression",
-    "FATEObjectRanker",
-    "FATELinearObjectRanker",
-    "FETAObjectRanker",
-    "FETALinearObjectRanker",
-    "ListNet",
-    "RankNet",
-    "RankSVM",
-    "RandomBaselineRanker",
+algorithms = [
+    CmpNet,
+    ExpectedRankRegression,
+    FATEObjectRanker,
+    FATELinearObjectRanker,
+    FETAObjectRanker,
+    FETALinearObjectRanker,
+    ListNet,
+    RankNet,
+    RankSVM,
+    RandomBaselineRanker,
 ]
+
+__all__ = [algo.__name__ for algo in algorithms]

csrank/tests/test_estimators.py

@@ -0,0 +1,70 @@
+"""Check that our estimators adhere to the scikit-learn interface.
+
+https://scikit-learn.org/stable/developers/develop.html#rolling-your-own-estimator
+"""
+
+from functools import partial
+
+import pytest
+from sklearn.utils.estimator_checks import check_estimator
+
+from csrank import objectranking
+
+
+def get_check_name(check):
+    if isinstance(check, partial):
+        return check.func.__name__
+    else:
+        return check.__name__
+
+
+def _reshape_x(X):
+    n_instances, n_objects = X.shape
+    n_features = 1
+    return X.reshape((n_instances, n_objects, n_features))
+
+
+@pytest.mark.parametrize(
+    "Estimator",
+    # TODO write wrappers for choice, discretechoice
+    objectranking.algorithms,
+)
+def test_all_estimators(Estimator):
+    class WrappedRanker(Estimator):
+        # scikit learn assumes that "X" is an array of one-dimensional
+        # feature vectors. Our learners however assume an array of objects
+        # as a "feature vector", hence they expect one more dimension.
+        # This is one scikit-learn API expectation that we do not fulfill.
+        # This thin wrapper is needed so that we can still use the other
+        # estimator checks. It just pretends every feature is itself a
+        # one-feature object.
+        def fit(self, X, Y, *args, **kwargs):
+            Xnew = _reshape_x(X)
+            Ynew = Xnew.argsort(axis=1).argsort(axis=1).squeeze(axis=-1)
+            return super().fit(Xnew, Ynew, *args, **kwargs)
+
+        def predict(self, X, *args, **kwargs):
+            super().predict(_reshape_x(X), *args, **kwargs)
+
+    for (estimator, check) in check_estimator(WrappedRanker, generate_only=True):
+        # checks that attempt to call "fit" do not work since our estimators
+        # expect a 3-dimensional data shape while scikit-learn assumes two
+        # dimensions (an array of 1d data).
+        if not get_check_name(check) in {
+            "check_estimators_fit_returns_self",  # fails for all
+            "check_complex_data",  # fails for CmpNet
+            "check_dtype_object",  # fails for ExpectedRankRegression
+            "check_estimators_empty_data_messages",  # fails for all
+            "check_estimators_nan_inf",  # fails for CmpNet
+            "check_estimators_overwrite_params",  # fails for FATELinearObjectRanker
+            "check_estimator_sparse_data",  # fails for ExpectedRankRegression
+            "check_estimators_pickle",  # fails for ExpectedRankRegression
+            "check_fit2d_predict1d",  # fails for ExpectedRankRegression
+            "check_methods_subset_invariance",  # fails for ExpectedRankRegression
+            "check_fit2d_1sample",  # fails for FETAObjectRanker
+            "check_dict_unchanged",  # fails for ListNet
+            "check_dont_overwrite_parameters",  # fails for CmpNet
+            "check_fit_idempotent",  # fails for ExpectedRankRegression
+            "check_n_features_in" # fails for RankSVM
+        }:
+            check(estimator)

shell.nix

@@ -21,6 +21,11 @@ let
           buildInputs = with pkgs; [ xorg.libX11 ] ++ old.buildInputs;
         }
       );
+      scikit-learn = super.scikit-learn.overridePythonAttrs (
+        old: {
+          patches = [./0001-Relax-init-parameter-type-checks.patch];
+        }
+      );
     });
   };
 in pkgs.mkShell {