Fix/no lambda function in add_encoders

CHANGELOG.md

@@ -19,6 +19,7 @@ but cannot always guarantee backwards compatibility. Changes that may **break co
 - Fixed a bug in `RegressionEnsembleModel.extreme_lags` when the forecasting models have only covariates lags. [#1942](https://github.com/unit8co/darts/pull/1942) by [Antoine Madrona](https://github.com/madtoinou).
 - Fixed a bug when using `TFTExplainer` with a `TFTModel` running on GPU. [#1949](https://github.com/unit8co/darts/pull/1949) by [Dennis Bader](https://github.com/dennisbader).
 - Fixed a bug in `TorchForecastingModel.load_weights()` that raised an error when loading the weights from a valid architecture. [#1952](https://github.com/unit8co/darts/pull/1952) by [Antoine Madrona](https://github.com/madtoinou).
+- 🔴 Dropped support for lambda functions in `add_encoders`’s “custom” encoder in favor of named functions to ensure that models can be exported. [#1957](https://github.com/unit8co/darts/pull/1957) by [Antoine Madrona]
 
 ### For developers of the library:
 

darts/dataprocessing/encoders/encoders.py

@@ -1362,6 +1362,7 @@ def _process_input_encoders(self, params: Dict) -> Tuple[List, List]:
         ValueError
             1) if the outermost key is other than (`past`, `future`)
             2) if the innermost values are other than type `str` or `Sequence`
+            3) if any of entry in the innermost values is a lambda function
         """
         if not params:
             return [], []
@@ -1377,9 +1378,7 @@ def _process_input_encoders(self, params: Dict) -> Tuple[List, List]:
             logger,
         )
 
-        encoders = {
-            enc: params.get(enc, None) for enc in ENCODER_KEYS if params.get(enc, None)
-        }
+        encoders = {enc: params[enc] for enc in ENCODER_KEYS if params.get(enc, None)}
 
         # check input for invalid temporal types
         invalid_time_params = list()
@@ -1395,6 +1394,8 @@ def _process_input_encoders(self, params: Dict) -> Tuple[List, List]:
             logger,
         )
 
+        # check that encoders are not lambda functions (not pickable)
+        lambda_func_encoders = set()
         # convert into tuples of (encoder string identifier, encoder attribute)
         past_encoders, future_encoders = list(), list()
         for enc, enc_params in encoders.items():
@@ -1414,6 +1415,18 @@ def _process_input_encoders(self, params: Dict) -> Tuple[List, List]:
                     else:
                         future_encoders.append((encoder_id, attr))
 
+                    if isinstance(attr, Callable) and attr.__name__ == "<lambda>":
+                        lambda_func_encoders.add(enc)
+
+        raise_if(
+            len(lambda_func_encoders) > 0,
+            f"Encountered lambda function in the following `add_encoders` entries : {lambda_func_encoders} "
+            f"at model creation. "
+            f"In order to prevent issues when saving the model, these encoders must be converted to "
+            f"named functions.",
+            logger,
+        )
+
         for temp_enc, takes_temp, temp in [
             (past_encoders, self.takes_past_covariates, "past"),
             (future_encoders, self.takes_future_covariates, "future"),

darts/models/forecasting/block_rnn_model.py

@@ -234,11 +234,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/catboost_model.py

@@ -66,11 +66,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/dlinear.py

@@ -335,11 +335,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/lgbm.py

@@ -75,11 +75,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/linear_regression_model.py

@@ -65,11 +65,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/nbeats.py

@@ -656,11 +656,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/nhits.py

@@ -592,11 +592,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/nlinear.py

@@ -286,11 +286,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/random_forest.py

@@ -70,11 +70,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/regression_model.py

@@ -106,11 +106,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..
@@ -1334,11 +1337,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/rnn_model.py

@@ -321,11 +321,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/tcn_model.py

@@ -357,11 +357,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/tft_model.py

@@ -804,11 +804,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/tide_model.py

@@ -461,11 +461,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/torch_forecasting_model.py

@@ -202,11 +202,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/transformer_model.py

@@ -445,11 +445,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..

darts/models/forecasting/xgboost.py

@@ -87,11 +87,14 @@ def __init__(
             .. highlight:: python
             .. code-block:: python
 
+                def encode_year(idx):
+                    return (idx.year - 1950) / 50
+
                 add_encoders={
                     'cyclic': {'future': ['month']},
                     'datetime_attribute': {'future': ['hour', 'dayofweek']},
                     'position': {'past': ['relative'], 'future': ['relative']},
-                    'custom': {'past': [lambda idx: (idx.year - 1950) / 50]},
+                    'custom': {'past': [encode_year]},
                     'transformer': Scaler()
                 }
             ..