Replace dask_ml.wrappers.Incremental with custom Incremental class

dask_sql/physical/rel/custom/create_experiment.py

@@ -30,9 +30,6 @@ class CreateExperimentPlugin(BaseRelPlugin):
     * model_class: Full path to the class of the model which has to be tuned.
       Any model class with sklearn interface is valid, but might or
       might not work well with Dask dataframes.
-      Have a look into the
-      [dask-ml documentation](https://ml.dask.org/index.html)
-      for more information on which models work best.
       You might need to install necessary packages to use
       the models.
     * experiment_class : Full path of the Hyperparameter tuner
@@ -64,7 +61,7 @@ class CreateExperimentPlugin(BaseRelPlugin):
 
             CREATE EXPERIMENT my_exp WITH(
             model_class = 'sklearn.ensemble.GradientBoostingClassifier',
-            experiment_class = 'dask_ml.model_selection.GridSearchCV',
+            experiment_class = 'sklearn.model_selection.GridSearchCV',
             tune_parameters = (n_estimators = ARRAY [16, 32, 2],
                                 learning_rate = ARRAY [0.1,0.01,0.001],
                                max_depth = ARRAY [3,4,5,10]

dask_sql/physical/rel/custom/create_model.py

@@ -32,9 +32,6 @@ class CreateModelPlugin(BaseRelPlugin):
     * model_class: Full path to the class of the model to train.
       Any model class with sklearn interface is valid, but might or
       might not work well with Dask dataframes.
-      Have a look into the
-      [dask-ml documentation](https://ml.dask.org/index.html)
-      for more information on which models work best.
       You might need to install necessary packages to use
       the models.
     * target_column: Which column from the data to use as target.
@@ -45,16 +42,12 @@ class CreateModelPlugin(BaseRelPlugin):
       want to set this parameter.
     * wrap_predict: Boolean flag, whether to wrap the selected
       model with a :class:`dask_sql.physical.rel.custom.wrappers.ParallelPostFit`.
-      Have a look into the
-      [dask-ml docu](https://ml.dask.org/meta-estimators.html#parallel-prediction-and-transformation)
-      to learn more about it. Defaults to false. Typically you set
-      it to true for sklearn models if predicting on big data.
+      Defaults to false. Typically you set it to true for
+      sklearn models if predicting on big data.
     * wrap_fit: Boolean flag, whether to wrap the selected
-      model with a :class:`dask_ml.wrappers.Incremental`.
-      Have a look into the
-      [dask-ml docu](https://ml.dask.org/incremental.html)
-      to learn more about it. Defaults to false. Typically you set
-      it to true for sklearn models if training on big data.
+      model with a :class:`dask_sql.physical.rel.custom.wrappers.Incremental`.
+      Defaults to false. Typically you set it to true for
+      sklearn models if training on big data.
     * fit_kwargs: keyword arguments sent to the call to fit().
 
     All other arguments are passed to the constructor of the
@@ -76,7 +69,7 @@ class CreateModelPlugin(BaseRelPlugin):
     Examples:
 
         CREATE MODEL my_model WITH (
-            model_class = 'dask_ml.xgboost.XGBClassifier',
+            model_class = 'sklearn.ensemble.GradientBoostingClassifier',
             target_column = 'target'
         ) AS (
             SELECT x, y, target
@@ -95,11 +88,10 @@ class CreateModelPlugin(BaseRelPlugin):
         dask dataframes.
 
         * if you are training on relatively small amounts
-          of data but predicting on large data samples
-          (and you are not using a model build for usage with dask
-          from the dask-ml package), you might want to set
-          `wrap_predict` to True. With this option,
-          model interference will be parallelized/distributed.
+          of data but predicting on large data samples,
+          you might want to set `wrap_predict` to True.
+          With this option, model interference will be
+          parallelized/distributed.
         * If you are training on large amounts of data,
           you can try setting wrap_fit to True. This will
           do the same on the training step, but works only on
@@ -158,10 +150,7 @@ def convert(self, rel: "LogicalPlan", context: "dask_sql.Context") -> DataContai
 
         model = ModelClass(**kwargs)
         if wrap_fit:
-            try:
-                from dask_ml.wrappers import Incremental
-            except ImportError:  # pragma: no cover
-                raise ValueError("Wrapping requires dask-ml to be installed.")
+            from dask_sql.physical.rel.custom.wrappers import Incremental
 
             model = Incremental(estimator=model)
 

dask_sql/physical/rel/custom/metrics.py

@@ -0,0 +1,206 @@
+# Copyright 2017, Dask developers
+# Dask-ML project - https://github.com/dask/dask-ml
+from typing import Optional, TypeVar
+
+import dask
+import dask.array as da
+import numpy as np
+import sklearn.metrics
+import sklearn.utils.multiclass
+from dask.array import Array
+from dask.utils import derived_from
+
+ArrayLike = TypeVar("ArrayLike", Array, np.ndarray)
+
+
+def accuracy_score(
+    y_true: ArrayLike,
+    y_pred: ArrayLike,
+    normalize: bool = True,
+    sample_weight: Optional[ArrayLike] = None,
+    compute: bool = True,
+) -> ArrayLike:
+    """Accuracy classification score.
+    In multilabel classification, this function computes subset accuracy:
+    the set of labels predicted for a sample must *exactly* match the
+    corresponding set of labels in y_true.
+    Read more in the :ref:`User Guide <accuracy_score>`.
+    Parameters
+    ----------
+    y_true : 1d array-like, or label indicator array
+        Ground truth (correct) labels.
+    y_pred : 1d array-like, or label indicator array
+        Predicted labels, as returned by a classifier.
+    normalize : bool, optional (default=True)
+        If ``False``, return the number of correctly classified samples.
+        Otherwise, return the fraction of correctly classified samples.
+    sample_weight : 1d array-like, optional
+        Sample weights.
+        .. versionadded:: 0.7.0
+    Returns
+    -------
+    score : scalar dask Array
+        If ``normalize == True``, return the correctly classified samples
+        (float), else it returns the number of correctly classified samples
+        (int).
+        The best performance is 1 with ``normalize == True`` and the number
+        of samples with ``normalize == False``.
+    Notes
+    -----
+    In binary and multiclass classification, this function is equal
+    to the ``jaccard_similarity_score`` function.
+
+    """
+
+    if y_true.ndim > 1:
+        differing_labels = ((y_true - y_pred) == 0).all(1)
+        score = differing_labels != 0
+    else:
+        score = y_true == y_pred
+
+    if normalize:
+        score = da.average(score, weights=sample_weight)
+    elif sample_weight is not None:
+        score = da.dot(score, sample_weight)
+    else:
+        score = score.sum()
+
+    if compute:
+        score = score.compute()
+    return score
+
+
+def _log_loss_inner(
+    x: ArrayLike, y: ArrayLike, sample_weight: Optional[ArrayLike], **kwargs
+):
+    # da.map_blocks wasn't able to concatenate together the results
+    # when we reduce down to a scalar per block. So we make an
+    # array with 1 element.
+    if sample_weight is not None:
+        sample_weight = sample_weight.ravel()
+    return np.array(
+        [sklearn.metrics.log_loss(x, y, sample_weight=sample_weight, **kwargs)]
+    )
+
+
+def log_loss(
+    y_true, y_pred, eps=1e-15, normalize=True, sample_weight=None, labels=None
+):
+    if not (dask.is_dask_collection(y_true) and dask.is_dask_collection(y_pred)):
+        return sklearn.metrics.log_loss(
+            y_true,
+            y_pred,
+            eps=eps,
+            normalize=normalize,
+            sample_weight=sample_weight,
+            labels=labels,
+        )
+
+    if y_pred.ndim > 1 and y_true.ndim == 1:
+        y_true = y_true.reshape(-1, 1)
+        drop_axis: Optional[int] = 1
+        if sample_weight is not None:
+            sample_weight = sample_weight.reshape(-1, 1)
+    else:
+        drop_axis = None
+
+    result = da.map_blocks(
+        _log_loss_inner,
+        y_true,
+        y_pred,
+        sample_weight,
+        chunks=(1,),
+        drop_axis=drop_axis,
+        dtype="f8",
+        eps=eps,
+        normalize=normalize,
+        labels=labels,
+    )
+    if normalize and sample_weight is not None:
+        sample_weight = sample_weight.ravel()
+        block_weights = sample_weight.map_blocks(np.sum, chunks=(1,), keepdims=True)
+        return da.average(result, 0, weights=block_weights)
+    elif normalize:
+        return result.mean()
+    else:
+        return result.sum()
+
+
+def _check_sample_weight(sample_weight: Optional[ArrayLike]):
+    if sample_weight is not None:
+        raise ValueError("'sample_weight' is not supported.")
+
+
+@derived_from(sklearn.metrics)
+def mean_squared_error(
+    y_true: ArrayLike,
+    y_pred: ArrayLike,
+    sample_weight: Optional[ArrayLike] = None,
+    multioutput: Optional[str] = "uniform_average",
+    squared: bool = True,
+    compute: bool = True,
+) -> ArrayLike:
+    _check_sample_weight(sample_weight)
+    output_errors = ((y_pred - y_true) ** 2).mean(axis=0)
+
+    if isinstance(multioutput, str) or multioutput is None:
+        if multioutput == "raw_values":
+            if compute:
+                return output_errors.compute()
+            else:
+                return output_errors
+    else:
+        raise ValueError("Weighted 'multioutput' not supported.")
+    result = output_errors.mean()
+    if not squared:
+        result = da.sqrt(result)
+    if compute:
+        result = result.compute()
+    return result
+
+
+def _check_reg_targets(
+    y_true: ArrayLike, y_pred: ArrayLike, multioutput: Optional[str]
+):
+    if multioutput is not None and multioutput != "uniform_average":
+        raise NotImplementedError("'multioutput' must be 'uniform_average'")
+
+    if y_true.ndim == 1:
+        y_true = y_true.reshape((-1, 1))
+    if y_pred.ndim == 1:
+        y_pred = y_pred.reshape((-1, 1))
+
+    # TODO: y_type, multioutput
+    return None, y_true, y_pred, multioutput
+
+
+@derived_from(sklearn.metrics)
+def r2_score(
+    y_true: ArrayLike,
+    y_pred: ArrayLike,
+    sample_weight: Optional[ArrayLike] = None,
+    multioutput: Optional[str] = "uniform_average",
+    compute: bool = True,
+) -> ArrayLike:
+    _check_sample_weight(sample_weight)
+    _, y_true, y_pred, _ = _check_reg_targets(y_true, y_pred, multioutput)
+    weight = 1.0
+
+    numerator = (weight * (y_true - y_pred) ** 2).sum(axis=0, dtype="f8")
+    denominator = (weight * (y_true - y_true.mean(axis=0)) ** 2).sum(axis=0, dtype="f8")
+
+    nonzero_denominator = denominator != 0
+    nonzero_numerator = numerator != 0
+    valid_score = nonzero_denominator & nonzero_numerator
+    output_chunks = getattr(y_true, "chunks", [None, None])[1]
+    output_scores = da.ones([y_true.shape[1]], chunks=output_chunks)
+    with np.errstate(all="ignore"):
+        output_scores[valid_score] = 1 - (
+            numerator[valid_score] / denominator[valid_score]
+        )
+        output_scores[nonzero_numerator & ~nonzero_denominator] = 0.0
+
+    result = output_scores.mean(axis=0)
+    if compute:
+        result = result.compute()
+    return result