mengxr commented on code in PR #37734: URL: https://github.com/apache/spark/pull/37734#discussion_r969862754
########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: Review Comment: Should it be a private method? ########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: + """Generator that splits a pandas dataframe/series into batches.""" + if batch_size <= 0 or batch_size >= len(df): + yield df + else: + # for batch in np.array_split(df, (len(df.index) + batch_size - 1) // batch_size): + for _, batch in df.groupby(np.arange(len(df)) // batch_size): + yield batch + + +def has_tensor_cols(df: pd.DataFrame) -> bool: + """Check if input DataFrame contains any tensor-valued columns""" + if any(df.dtypes == np.object_): + # pd.DataFrame object types can contain different types, e.g. string, dates, etc. + # so inspect a row and check for array/list type + sample = df.iloc[0] + return any([isinstance(x, np.ndarray) or isinstance(x, list) for x in sample]) + else: + return False + + +def batch_infer_udf( + predict_batch_fn: Callable, + return_type: DataType = ArrayType(FloatType()), Review Comment: * Please use `*` to force keyword-only. I think only the first param is trivial to guess. * Maybe enforce return type instead of having a default. ########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: + """Generator that splits a pandas dataframe/series into batches.""" + if batch_size <= 0 or batch_size >= len(df): + yield df + else: + # for batch in np.array_split(df, (len(df.index) + batch_size - 1) // batch_size): + for _, batch in df.groupby(np.arange(len(df)) // batch_size): + yield batch + + +def has_tensor_cols(df: pd.DataFrame) -> bool: + """Check if input DataFrame contains any tensor-valued columns""" + if any(df.dtypes == np.object_): + # pd.DataFrame object types can contain different types, e.g. string, dates, etc. + # so inspect a row and check for array/list type + sample = df.iloc[0] + return any([isinstance(x, np.ndarray) or isinstance(x, list) for x in sample]) + else: + return False + + +def batch_infer_udf( + predict_batch_fn: Callable, + return_type: DataType = ArrayType(FloatType()), + batch_size: int = -1, + input_names: list[str] = [], + input_tensor_shapes: list[list[int]] = [], + **kwargs: Any, +) -> Callable: Review Comment: It returns a Pandas UDF. ########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: + """Generator that splits a pandas dataframe/series into batches.""" + if batch_size <= 0 or batch_size >= len(df): + yield df + else: + # for batch in np.array_split(df, (len(df.index) + batch_size - 1) // batch_size): + for _, batch in df.groupby(np.arange(len(df)) // batch_size): + yield batch + + +def has_tensor_cols(df: pd.DataFrame) -> bool: + """Check if input DataFrame contains any tensor-valued columns""" + if any(df.dtypes == np.object_): + # pd.DataFrame object types can contain different types, e.g. string, dates, etc. + # so inspect a row and check for array/list type + sample = df.iloc[0] + return any([isinstance(x, np.ndarray) or isinstance(x, list) for x in sample]) + else: + return False + + +def batch_infer_udf( + predict_batch_fn: Callable, + return_type: DataType = ArrayType(FloatType()), + batch_size: int = -1, + input_names: list[str] = [], + input_tensor_shapes: list[list[int]] = [], + **kwargs: Any, +) -> Callable: + """Given a function which loads a model, returns a pandas_udf for inferencing over that model. + + This will handle: + - conversion of the Spark DataFrame to numpy arrays. + - batching of the inputs sent to the model predict() function. + - caching of the model and prediction function on the executors. + + This assumes that the `predict_batch_fn` encapsulates all of the necessary dependencies for + running the model or the Spark executor environment already satisfies all runtime requirements. + + When selecting columns in pyspark SQL, users are required to always use `struct` for simplicity. + + For the conversion of Spark DataFrame to numpy, the following table describes the behavior, + where tensor columns in the Spark DataFrame must be represented as a flattened 1-D array/list. + + | dataframe \\ model | single input | multiple inputs | + | :----------------- | :----------- | :-------------- | + | single-col scalar | 1 | N/A | + | single-col tensor | 1,2 | N/A | + | multi-col scalar | 3 | 4 | Review Comment: I feel we don't need to support this scenario. Users can use SQL function `array` to do the same. ########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: + """Generator that splits a pandas dataframe/series into batches.""" + if batch_size <= 0 or batch_size >= len(df): + yield df + else: + # for batch in np.array_split(df, (len(df.index) + batch_size - 1) // batch_size): + for _, batch in df.groupby(np.arange(len(df)) // batch_size): + yield batch + + +def has_tensor_cols(df: pd.DataFrame) -> bool: + """Check if input DataFrame contains any tensor-valued columns""" + if any(df.dtypes == np.object_): + # pd.DataFrame object types can contain different types, e.g. string, dates, etc. + # so inspect a row and check for array/list type + sample = df.iloc[0] + return any([isinstance(x, np.ndarray) or isinstance(x, list) for x in sample]) + else: + return False + + +def batch_infer_udf( + predict_batch_fn: Callable, + return_type: DataType = ArrayType(FloatType()), + batch_size: int = -1, + input_names: list[str] = [], + input_tensor_shapes: list[list[int]] = [], + **kwargs: Any, +) -> Callable: + """Given a function which loads a model, returns a pandas_udf for inferencing over that model. + + This will handle: + - conversion of the Spark DataFrame to numpy arrays. + - batching of the inputs sent to the model predict() function. + - caching of the model and prediction function on the executors. + + This assumes that the `predict_batch_fn` encapsulates all of the necessary dependencies for + running the model or the Spark executor environment already satisfies all runtime requirements. + + When selecting columns in pyspark SQL, users are required to always use `struct` for simplicity. Review Comment: I guess this is the main design discussion. ########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: + """Generator that splits a pandas dataframe/series into batches.""" + if batch_size <= 0 or batch_size >= len(df): + yield df + else: + # for batch in np.array_split(df, (len(df.index) + batch_size - 1) // batch_size): + for _, batch in df.groupby(np.arange(len(df)) // batch_size): + yield batch + + +def has_tensor_cols(df: pd.DataFrame) -> bool: + """Check if input DataFrame contains any tensor-valued columns""" + if any(df.dtypes == np.object_): + # pd.DataFrame object types can contain different types, e.g. string, dates, etc. + # so inspect a row and check for array/list type + sample = df.iloc[0] + return any([isinstance(x, np.ndarray) or isinstance(x, list) for x in sample]) + else: + return False + + +def batch_infer_udf( + predict_batch_fn: Callable, + return_type: DataType = ArrayType(FloatType()), + batch_size: int = -1, + input_names: list[str] = [], + input_tensor_shapes: list[list[int]] = [], + **kwargs: Any, +) -> Callable: + """Given a function which loads a model, returns a pandas_udf for inferencing over that model. + + This will handle: + - conversion of the Spark DataFrame to numpy arrays. + - batching of the inputs sent to the model predict() function. + - caching of the model and prediction function on the executors. + + This assumes that the `predict_batch_fn` encapsulates all of the necessary dependencies for + running the model or the Spark executor environment already satisfies all runtime requirements. + + When selecting columns in pyspark SQL, users are required to always use `struct` for simplicity. + + For the conversion of Spark DataFrame to numpy, the following table describes the behavior, + where tensor columns in the Spark DataFrame must be represented as a flattened 1-D array/list. + + | dataframe \\ model | single input | multiple inputs | + | :----------------- | :----------- | :-------------- | + | single-col scalar | 1 | N/A | + | single-col tensor | 1,2 | N/A | + | multi-col scalar | 3 | 4 | + | multi-col tensor | N/A | 4,2 | + + Notes: + 1. pass thru dataframe column => model input as single numpy array. + 2. reshape flattened tensors into expected tensor shapes. + 3. convert entire dataframe into single numpy array via df.to_numpy(), or user can use + `pyspark.sql.functions.array()` to transform the input into a single-col tensor first. + 4. pass thru dataframe column => model input as an (ordered) dictionary of numpy arrays. + + Parameters + ---------- + predict_batch_fn : Callable Review Comment: Should provide accepted signatures and examples in the API doc. ########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: + """Generator that splits a pandas dataframe/series into batches.""" + if batch_size <= 0 or batch_size >= len(df): + yield df + else: + # for batch in np.array_split(df, (len(df.index) + batch_size - 1) // batch_size): + for _, batch in df.groupby(np.arange(len(df)) // batch_size): + yield batch + + +def has_tensor_cols(df: pd.DataFrame) -> bool: + """Check if input DataFrame contains any tensor-valued columns""" + if any(df.dtypes == np.object_): + # pd.DataFrame object types can contain different types, e.g. string, dates, etc. + # so inspect a row and check for array/list type + sample = df.iloc[0] + return any([isinstance(x, np.ndarray) or isinstance(x, list) for x in sample]) + else: + return False + + +def batch_infer_udf( + predict_batch_fn: Callable, + return_type: DataType = ArrayType(FloatType()), + batch_size: int = -1, + input_names: list[str] = [], + input_tensor_shapes: list[list[int]] = [], + **kwargs: Any, +) -> Callable: + """Given a function which loads a model, returns a pandas_udf for inferencing over that model. + + This will handle: + - conversion of the Spark DataFrame to numpy arrays. + - batching of the inputs sent to the model predict() function. + - caching of the model and prediction function on the executors. + + This assumes that the `predict_batch_fn` encapsulates all of the necessary dependencies for + running the model or the Spark executor environment already satisfies all runtime requirements. + + When selecting columns in pyspark SQL, users are required to always use `struct` for simplicity. + + For the conversion of Spark DataFrame to numpy, the following table describes the behavior, + where tensor columns in the Spark DataFrame must be represented as a flattened 1-D array/list. + + | dataframe \\ model | single input | multiple inputs | + | :----------------- | :----------- | :-------------- | + | single-col scalar | 1 | N/A | + | single-col tensor | 1,2 | N/A | + | multi-col scalar | 3 | 4 | + | multi-col tensor | N/A | 4,2 | + + Notes: + 1. pass thru dataframe column => model input as single numpy array. + 2. reshape flattened tensors into expected tensor shapes. + 3. convert entire dataframe into single numpy array via df.to_numpy(), or user can use + `pyspark.sql.functions.array()` to transform the input into a single-col tensor first. + 4. pass thru dataframe column => model input as an (ordered) dictionary of numpy arrays. + + Parameters + ---------- + predict_batch_fn : Callable + Function which is responsible for loading a model and returning a `predict` function. + return_type : :class:`pspark.sql.types.DataType` or str. + Spark SQL datatype for the expected output. + Default: ArrayType(FloatType()) + batch_size : int + Batch size to use for inference, note that this is typically a limitation of the model + and/or the hardware resources and is usually smaller than the Spark partition size. + Default: -1, which sends the entire Spark partition to the model. Review Comment: Instead of making the default to the entire partition, I would leave it to "auto" (`None`). I think in the future we can automatically estimate a good step size to use based on memory and CPU/GPU utilization. Default to the entire partition is error-prone. In the first version, we can be conservative about the default batch size or simply make it a required param. ########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: + """Generator that splits a pandas dataframe/series into batches.""" + if batch_size <= 0 or batch_size >= len(df): + yield df + else: + # for batch in np.array_split(df, (len(df.index) + batch_size - 1) // batch_size): + for _, batch in df.groupby(np.arange(len(df)) // batch_size): + yield batch + + +def has_tensor_cols(df: pd.DataFrame) -> bool: + """Check if input DataFrame contains any tensor-valued columns""" + if any(df.dtypes == np.object_): + # pd.DataFrame object types can contain different types, e.g. string, dates, etc. + # so inspect a row and check for array/list type + sample = df.iloc[0] + return any([isinstance(x, np.ndarray) or isinstance(x, list) for x in sample]) + else: + return False + + +def batch_infer_udf( Review Comment: I think we can call it "predict_batch_udf" to match "predict_batch_fn" param name. ########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: + """Generator that splits a pandas dataframe/series into batches.""" + if batch_size <= 0 or batch_size >= len(df): + yield df + else: + # for batch in np.array_split(df, (len(df.index) + batch_size - 1) // batch_size): + for _, batch in df.groupby(np.arange(len(df)) // batch_size): + yield batch + + +def has_tensor_cols(df: pd.DataFrame) -> bool: + """Check if input DataFrame contains any tensor-valued columns""" + if any(df.dtypes == np.object_): + # pd.DataFrame object types can contain different types, e.g. string, dates, etc. + # so inspect a row and check for array/list type + sample = df.iloc[0] + return any([isinstance(x, np.ndarray) or isinstance(x, list) for x in sample]) + else: + return False + + +def batch_infer_udf( + predict_batch_fn: Callable, + return_type: DataType = ArrayType(FloatType()), + batch_size: int = -1, + input_names: list[str] = [], Review Comment: * Shouldn't use mutable `[]` as default value. Use `None` instead. * Not sure if we need this param in the first version. We can restrict the input to either: ** One value column (no name), `model_udf(c1)` ** A struct column (caller can rename the sub-columns if needed). `model_udf(struct(c1, c2))`. Or another option is to accept a list of columns `(model_udf(c1, c2))`. `predict_batch_fn` and `input_tensor_shapes` signature should match accordingly. I slightly prefer the latter which doesn't need to handle name conflicts and we can use list for tensor shapes. ########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: + """Generator that splits a pandas dataframe/series into batches.""" + if batch_size <= 0 or batch_size >= len(df): + yield df + else: + # for batch in np.array_split(df, (len(df.index) + batch_size - 1) // batch_size): + for _, batch in df.groupby(np.arange(len(df)) // batch_size): + yield batch + + +def has_tensor_cols(df: pd.DataFrame) -> bool: + """Check if input DataFrame contains any tensor-valued columns""" + if any(df.dtypes == np.object_): + # pd.DataFrame object types can contain different types, e.g. string, dates, etc. + # so inspect a row and check for array/list type + sample = df.iloc[0] + return any([isinstance(x, np.ndarray) or isinstance(x, list) for x in sample]) + else: + return False + + +def batch_infer_udf( + predict_batch_fn: Callable, Review Comment: Any type hints we can specify here? ########## python/pyspark/ml/functions.py: ########## @@ -106,6 +111,167 @@ def array_to_vector(col: Column) -> Column: return Column(sc._jvm.org.apache.spark.ml.functions.array_to_vector(_to_java_column(col))) +def batched(df: pd.DataFrame, batch_size: int = -1) -> Iterator[pd.DataFrame]: + """Generator that splits a pandas dataframe/series into batches.""" + if batch_size <= 0 or batch_size >= len(df): + yield df + else: + # for batch in np.array_split(df, (len(df.index) + batch_size - 1) // batch_size): + for _, batch in df.groupby(np.arange(len(df)) // batch_size): + yield batch + + +def has_tensor_cols(df: pd.DataFrame) -> bool: Review Comment: Ditto. -- This is an automated message from the Apache Git Service. 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