Feature/epochs for als

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 - `from_config`, `get_config` and `get_params` methods to all models except neural-net-based([#170](https://github.com/MobileTeleSystems/RecTools/pull/170))
+- Optional `epochs` argument to `ImplicitALSWrapperModel.fit` method ([#203](https://github.com/MobileTeleSystems/RecTools/pull/203))
 
 
 ## [0.8.0] - 28.08.2024

rectools/models/implicit_als.py

@@ -197,16 +197,20 @@ def _from_config(cls, config: ImplicitALSWrapperModelConfig) -> tpe.Self:
         model = model_cls(**config.model.params)
         return cls(model=model, verbose=config.verbose, fit_features_together=config.fit_features_together)
 
-    def _fit(self, dataset: Dataset) -> None:  # type: ignore
+    # TODO: move to `epochs` argument of `partial_fit` method when implemented
+    def _fit(self, dataset: Dataset, epochs: tp.Optional[int] = None) -> None:  # type: ignore
         self.model = deepcopy(self._model)
         ui_csr = dataset.get_user_item_matrix(include_weights=True).astype(np.float32)
+        if epochs is None:
+            epochs = self.model.iterations
 
         if self.fit_features_together:
             fit_als_with_features_together_inplace(
                 self.model,
                 ui_csr,
                 dataset.get_hot_user_features(),
                 dataset.get_hot_item_features(),
+                epochs,
                 self.verbose,
             )
         else:
@@ -215,6 +219,7 @@ def _fit(self, dataset: Dataset) -> None:  # type: ignore
                 ui_csr,
                 dataset.get_hot_user_features(),
                 dataset.get_hot_item_features(),
+                epochs,
                 self.verbose,
             )
 
@@ -282,6 +287,7 @@ def fit_als_with_features_separately_inplace(
     ui_csr: sparse.csr_matrix,
     user_features: tp.Optional[Features],
     item_features: tp.Optional[Features],
+    iterations: int,
     verbose: int = 0,
 ) -> None:
     """
@@ -300,7 +306,15 @@ def fit_als_with_features_separately_inplace(
     verbose : int
          Whether to print output.
     """
+    # If model was fitted we should drop any learnt embeddings except actual latent factors
+    if model.user_factors is not None and model.item_factors is not None:
+        # Without .copy() gpu.Matrix will break correct slicing
+        user_factors = get_users_vectors(model)[:, : model.factors].copy()
+        item_factors = get_items_vectors(model)[:, : model.factors].copy()
+        _set_factors(model, user_factors, item_factors)
+
     iu_csr = ui_csr.T.tocsr(copy=False)
+    model.iterations = iterations
     model.fit(ui_csr, show_progress=verbose > 0)
 
     user_factors_chunks = [get_users_vectors(model)]
@@ -321,10 +335,13 @@ def fit_als_with_features_separately_inplace(
     user_factors = np.hstack(user_factors_chunks)
     item_factors = np.hstack(item_factors_chunks)
 
+    _set_factors(model, user_factors, item_factors)
+
+
+def _set_factors(model: AnyAlternatingLeastSquares, user_factors: np.ndarray, item_factors: np.ndarray) -> None:
     if isinstance(model, GPUAlternatingLeastSquares):  # pragma: no cover
         user_factors = implicit.gpu.Matrix(user_factors)
         item_factors = implicit.gpu.Matrix(item_factors)
-
     model.user_factors = user_factors
     model.item_factors = item_factors
 
@@ -363,36 +380,30 @@ def _fit_paired_factors(
 def _init_latent_factors_cpu(
     model: CPUAlternatingLeastSquares, n_users: int, n_items: int
 ) -> tp.Tuple[np.ndarray, np.ndarray]:
-    """Logic is copied and pasted from original implicit library code"""
+    """
+    Logic is copied and pasted from original implicit library code.
+    This method is used only for model that hasn't been fitted yet.
+    """
     random_state = check_random_state(model.random_state)
-    if model.user_factors is None:
-        user_latent_factors = random_state.random((n_users, model.factors)) * 0.01
-    else:
-        user_latent_factors = model.user_factors
-    if model.item_factors is None:
-        item_latent_factors = random_state.random((n_items, model.factors)) * 0.01
-    else:
-        item_latent_factors = model.item_factors
+    user_latent_factors = random_state.random((n_users, model.factors)) * 0.01
+    item_latent_factors = random_state.random((n_items, model.factors)) * 0.01
     return user_latent_factors, item_latent_factors
 
 
 def _init_latent_factors_gpu(
     model: GPUAlternatingLeastSquares, n_users: int, n_items: int
 ) -> tp.Tuple[np.ndarray, np.ndarray]:  # pragma: no cover
-    """Logic is copied and pasted from original implicit library code"""
+    """
+    Logic is copied and pasted from original implicit library code.
+    This method is used only for model that hasn't been fitted yet.
+    """
     random_state = check_random_state(model.random_state)
-    if model.user_factors is None:
-        user_latent_factors = random_state.uniform(
-            low=-0.5 / model.factors, high=0.5 / model.factors, size=(n_users, model.factors)
-        )
-    else:
-        user_latent_factors = model.user_factors.to_numpy()
-    if model.item_factors is None:
-        item_latent_factors = random_state.uniform(
-            low=-0.5 / model.factors, high=0.5 / model.factors, size=(n_items, model.factors)
-        )
-    else:
-        item_latent_factors = model.item_factors.to_numpy()
+    user_latent_factors = random_state.uniform(
+        low=-0.5 / model.factors, high=0.5 / model.factors, size=(n_users, model.factors)
+    )
+    item_latent_factors = random_state.uniform(
+        low=-0.5 / model.factors, high=0.5 / model.factors, size=(n_items, model.factors)
+    )
     return user_latent_factors, item_latent_factors
 
 
@@ -401,6 +412,7 @@ def fit_als_with_features_together_inplace(
     ui_csr: sparse.csr_matrix,
     user_features: tp.Optional[Features],
     item_features: tp.Optional[Features],
+    iterations: int,
     verbose: int = 0,
 ) -> None:
     """
@@ -421,6 +433,65 @@ def fit_als_with_features_together_inplace(
     """
     n_users, n_items = ui_csr.shape
 
+    if model.user_factors is None or model.item_factors is None:
+        user_factors, item_factors, n_user_explicit_factors, n_item_explicit_factors = (
+            _init_user_item_factors_for_combined_training_with_features(
+                model, n_users, n_items, user_features, item_features
+            )
+        )
+    else:
+        user_factors = get_users_vectors(model)
+        item_factors = get_items_vectors(model)
+        n_user_explicit_factors = user_features.values.shape[1] if user_features is not None else 0
+        n_item_explicit_factors = item_features.values.shape[1] if item_features is not None else 0
+
+    # Fix number of factors
+    n_latent_factors = model.factors
+    model.factors = n_latent_factors + n_user_explicit_factors + n_item_explicit_factors
+
+    # Give the positive examples more weight if asked for (implicit library logic copy)
+    ui_csr = model.alpha * ui_csr
+
+    if isinstance(model, GPUAlternatingLeastSquares):  # pragma: no cover
+        _fit_combined_factors_on_gpu_inplace(
+            model,
+            ui_csr,
+            user_factors,
+            item_factors,
+            n_user_explicit_factors,
+            n_item_explicit_factors,
+            verbose,
+            iterations,
+        )
+    else:
+        _fit_combined_factors_on_cpu_inplace(
+            model,
+            ui_csr,
+            user_factors,
+            item_factors,
+            n_user_explicit_factors,
+            n_item_explicit_factors,
+            verbose,
+            iterations,
+        )
+
+    # Fix back model factors
+    model.factors = n_latent_factors
+
+
+def _init_user_item_factors_for_combined_training_with_features(
+    model: AnyAlternatingLeastSquares,
+    n_users: int,
+    n_items: int,
+    user_features: tp.Optional[Features],
+    item_features: tp.Optional[Features],
+) -> tp.Tuple[np.ndarray, np.ndarray, int, int]:
+    """
+    Init user and item factors for model that hasn't been initialized yet.
+    Final factors will include latent factors, explicit factors from
+    user/item features and their paired item/user factors.
+    This method is only used when `fit_features_together` is set to ``True``
+    """
     # Prepare explicit factors
     user_explicit_factors: np.ndarray
     if user_features is None:
@@ -442,10 +513,6 @@ def fit_als_with_features_together_inplace(
     else:
         user_latent_factors, item_latent_factors = _init_latent_factors_cpu(model, n_users, n_items)
 
-    # Fix number of factors
-    n_latent_factors = model.factors
-    model.factors = n_latent_factors + n_user_explicit_factors + n_item_explicit_factors
-
     # Prepare paired factors
     user_factors_paired_to_items = np.zeros((n_users, n_item_explicit_factors))
     item_factors_paired_to_users = np.zeros((n_items, n_user_explicit_factors))
@@ -466,29 +533,7 @@ def fit_als_with_features_together_inplace(
         )
     ).astype(model.dtype)
 
-    # Give the positive examples more weight if asked for (implicit library logic copy)
-    ui_csr = model.alpha * ui_csr
-
-    if isinstance(model, GPUAlternatingLeastSquares):  # pragma: no cover
-        _fit_combined_factors_on_gpu_inplace(
-            model,
-            ui_csr,
-            user_factors,
-            item_factors,
-            n_user_explicit_factors,
-            n_item_explicit_factors,
-            verbose,
-        )
-    else:
-        _fit_combined_factors_on_cpu_inplace(
-            model,
-            ui_csr,
-            user_factors,
-            item_factors,
-            n_user_explicit_factors,
-            n_item_explicit_factors,
-            verbose,
-        )
+    return user_factors, item_factors, n_user_explicit_factors, n_item_explicit_factors
 
 
 def _fit_combined_factors_on_cpu_inplace(
@@ -499,6 +544,7 @@ def _fit_combined_factors_on_cpu_inplace(
     n_user_explicit_factors: int,
     n_item_explicit_factors: int,
     verbose: int,
+    iterations: int,
 ) -> None:
     n_factors = user_factors.shape[1]
     user_explicit_factors = user_factors[:, :n_user_explicit_factors].copy()
@@ -512,7 +558,7 @@ def _fit_combined_factors_on_cpu_inplace(
 
     solver = model.solver
 
-    for _ in tqdm(range(model.iterations), disable=verbose == 0):
+    for _ in tqdm(range(iterations), disable=verbose == 0):
 
         solver(
             ui_csr,
@@ -544,6 +590,7 @@ def _fit_combined_factors_on_gpu_inplace(
     n_user_explicit_factors: int,
     n_item_explicit_factors: int,
     verbose: int,
+    iterations: int,
 ) -> None:  # pragma: no cover
     n_factors = user_factors.shape[1]
     user_explicit_factors = user_factors[:, :n_user_explicit_factors].copy()
@@ -563,7 +610,7 @@ def _fit_combined_factors_on_gpu_inplace(
     _YtY = implicit.gpu.Matrix.zeros(model.factors, model.factors)
     _XtX = implicit.gpu.Matrix.zeros(model.factors, model.factors)
 
-    for _ in tqdm(range(model.iterations), disable=verbose == 0):
+    for _ in tqdm(range(iterations), disable=verbose == 0):
 
         model.solver.calculate_yty(Y, _YtY, model.regularization)
         model.solver.least_squares(ui_csr_cuda, X, _YtY, Y, model.cg_steps)

tests/models/test_implicit_als.py

@@ -30,6 +30,8 @@
     AnyAlternatingLeastSquares,
     CPUAlternatingLeastSquares,
     GPUAlternatingLeastSquares,
+    get_items_vectors,
+    get_users_vectors,
 )
 from rectools.models.utils import recommend_from_scores
 
@@ -64,6 +66,29 @@ def _init_model_factors_inplace(model: AnyAlternatingLeastSquares, dataset: Data
     def dataset(self) -> Dataset:
         return DATASET
 
+    @pytest.fixture
+    def dataset_w_features(self) -> Dataset:
+        user_id_map = IdMap.from_values(["u1", "u2", "u3"])
+        item_id_map = IdMap.from_values(["i1", "i2", "i3"])
+        interactions_df = pd.DataFrame(
+            [
+                ["u1", "i1", 0.1, "2021-09-09"],
+                ["u2", "i1", 0.1, "2021-09-09"],
+                ["u2", "i2", 0.5, "2021-09-05"],
+                ["u2", "i3", 0.2, "2021-09-05"],
+                ["u1", "i3", 0.2, "2021-09-05"],
+                ["u3", "i1", 0.2, "2021-09-05"],
+            ],
+            columns=[Columns.User, Columns.Item, Columns.Weight, Columns.Datetime],
+        )
+        interactions = Interactions.from_raw(interactions_df, user_id_map, item_id_map)
+        user_features_df = pd.DataFrame({"id": ["u1", "u2", "u3"], "f1": [0.3, 0.4, 0.5]})
+        user_features = DenseFeatures.from_dataframe(user_features_df, user_id_map)
+        item_features_df = pd.DataFrame({"id": ["i1", "i1"], "feature": ["f1", "f2"], "value": [2.1, 100]})
+        item_features = SparseFeatures.from_flatten(item_features_df, item_id_map)
+        dataset = Dataset(user_id_map, item_id_map, interactions, user_features, item_features)
+        return dataset
+
     @pytest.mark.parametrize(
         "filter_viewed,expected",
         (
@@ -206,26 +231,10 @@ def test_with_whitelist(
             ),
         ),
     )
-    def test_happy_path_with_features(self, fit_features_together: bool, expected: pd.DataFrame, use_gpu: bool) -> None:
-        user_id_map = IdMap.from_values(["u1", "u2", "u3"])
-        item_id_map = IdMap.from_values(["i1", "i2", "i3"])
-        interactions_df = pd.DataFrame(
-            [
-                ["u1", "i1", 0.1, "2021-09-09"],
-                ["u2", "i1", 0.1, "2021-09-09"],
-                ["u2", "i2", 0.5, "2021-09-05"],
-                ["u2", "i3", 0.2, "2021-09-05"],
-                ["u1", "i3", 0.2, "2021-09-05"],
-                ["u3", "i1", 0.2, "2021-09-05"],
-            ],
-            columns=[Columns.User, Columns.Item, Columns.Weight, Columns.Datetime],
-        )
-        interactions = Interactions.from_raw(interactions_df, user_id_map, item_id_map)
-        user_features_df = pd.DataFrame({"id": ["u1", "u2", "u3"], "f1": [0.3, 0.4, 0.5]})
-        user_features = DenseFeatures.from_dataframe(user_features_df, user_id_map)
-        item_features_df = pd.DataFrame({"id": ["i1", "i1"], "feature": ["f1", "f2"], "value": [2.1, 100]})
-        item_features = SparseFeatures.from_flatten(item_features_df, item_id_map)
-        dataset = Dataset(user_id_map, item_id_map, interactions, user_features, item_features)
+    def test_happy_path_with_features(
+        self, fit_features_together: bool, expected: pd.DataFrame, use_gpu: bool, dataset_w_features: Dataset
+    ) -> None:
+        dataset = dataset_w_features
 
         # In case of big number of iterations there are differences between CPU and GPU results
         base_model = AlternatingLeastSquares(factors=32, num_threads=2, use_gpu=use_gpu)
@@ -355,6 +364,39 @@ def test_i2i_with_warm_and_cold_items(self, use_gpu: bool, dataset: Dataset) ->
                 k=2,
             )
 
+    # TODO: move this test to `partial_fit` method when implemented
+    @pytest.mark.parametrize("fit_features_together", (False, True))
+    @pytest.mark.parametrize("use_features_in_dataset", (False, True))
+    def test_per_epoch_fitting_consistent_with_regular_fitting(
+        self,
+        dataset: Dataset,
+        dataset_w_features: Dataset,
+        fit_features_together: bool,
+        use_features_in_dataset: bool,
+        use_gpu: bool,
+    ) -> None:
+        if use_features_in_dataset:
+            dataset = dataset_w_features
+
+        iterations = 20
+
+        base_model_1 = AlternatingLeastSquares(
+            factors=2, num_threads=2, iterations=iterations, random_state=32, use_gpu=use_gpu
+        )
+        model_1 = ImplicitALSWrapperModel(model=base_model_1, fit_features_together=fit_features_together)
+        model_1.fit(dataset)
+
+        base_model_2 = AlternatingLeastSquares(
+            factors=2, num_threads=2, iterations=iterations, random_state=32, use_gpu=use_gpu
+        )
+        model_2 = ImplicitALSWrapperModel(model=base_model_2, fit_features_together=fit_features_together)
+        for _ in range(iterations):
+            model_2.fit(dataset, epochs=1)
+            model_2._model = deepcopy(model_2.model)  # pylint: disable=protected-access
+
+        assert np.allclose(get_users_vectors(model_1.model), get_users_vectors(model_2.model))
+        assert np.allclose(get_items_vectors(model_1.model), get_items_vectors(model_2.model))
+
 
 class CustomALS(CPUAlternatingLeastSquares):
     pass