Tune: Further file hierarchy improvements
This commit is contained in:
911
python/isaac/external/sklearn/utils.py
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911
python/isaac/external/sklearn/utils.py
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import sys
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import inspect
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import warnings
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import numbers
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import numpy as np
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################################ six ########################################
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PY2 = sys.version_info[0] == 2
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PY3 = sys.version_info[0] == 3
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if PY3:
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string_types = str
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_iteritems = "items"
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else:
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string_types = basestring
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_iteritems = "iteritems"
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def iteritems(d, **kw):
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"""Return an iterator over the (key, value) pairs of a dictionary."""
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return iter(getattr(d, _iteritems)(**kw))
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################################ utils ########################################
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if np.version < (1, 6, 2):
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# Allow bincount to accept empty arrays
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# https://github.com/numpy/numpy/commit/40f0844846a9d7665616b142407a3d74cb65a040
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def bincount(x, weights=None, minlength=None):
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if len(x) > 0:
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return np.bincount(x, weights, minlength)
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else:
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if minlength is None:
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minlength = 0
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minlength = np.asscalar(np.asarray(minlength, dtype=np.intp))
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return np.zeros(minlength, dtype=np.intp)
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else:
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from numpy import bincount
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class DataConversionWarning(UserWarning):
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"""A warning on implicit data conversions happening in the code"""
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pass
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class NotFittedError(ValueError, AttributeError):
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"""Exception class to raise if estimator is used before fitting
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This class inherits from both ValueError and AttributeError to help with
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exception handling and backward compatibility.
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"""
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def check_is_fitted(estimator, attributes, msg=None, all_or_any=all):
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"""Perform is_fitted validation for estimator.
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Checks if the estimator is fitted by verifying the presence of
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"all_or_any" of the passed attributes and raises a NotFittedError with the
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given message.
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Parameters
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----------
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estimator : estimator instance.
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estimator instance for which the check is performed.
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attributes : attribute name(s) given as string or a list/tuple of strings
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Eg. : ["coef_", "estimator_", ...], "coef_"
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msg : string
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The default error message is, "This %(name)s instance is not fitted
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yet. Call 'fit' with appropriate arguments before using this method."
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For custom messages if "%(name)s" is present in the message string,
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it is substituted for the estimator name.
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Eg. : "Estimator, %(name)s, must be fitted before sparsifying".
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all_or_any : callable, {all, any}, default all
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Specify whether all or any of the given attributes must exist.
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"""
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if msg is None:
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msg = ("This %(name)s instance is not fitted yet. Call 'fit' with "
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"appropriate arguments before using this method.")
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if not hasattr(estimator, 'fit'):
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raise TypeError("%s is not an estimator instance." % (estimator))
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if not isinstance(attributes, (list, tuple)):
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attributes = [attributes]
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if not all_or_any([hasattr(estimator, attr) for attr in attributes]):
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raise NotFittedError(msg % {'name': type(estimator).__name__})
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def compute_sample_weight(class_weight, y, indices=None):
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"""Estimate sample weights by class for unbalanced datasets.
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Parameters
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----------
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class_weight : dict, list of dicts, "auto", or None, optional
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Weights associated with classes in the form ``{class_label: weight}``.
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If not given, all classes are supposed to have weight one. For
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multi-output problems, a list of dicts can be provided in the same
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order as the columns of y.
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The "auto" mode uses the values of y to automatically adjust
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weights inversely proportional to class frequencies in the input data.
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For multi-output, the weights of each column of y will be multiplied.
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y : array-like, shape = [n_samples] or [n_samples, n_outputs]
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Array of original class labels per sample.
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indices : array-like, shape (n_subsample,), or None
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Array of indices to be used in a subsample. Can be of length less than
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n_samples in the case of a subsample, or equal to n_samples in the
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case of a bootstrap subsample with repeated indices. If None, the
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sample weight will be calculated over the full sample. Only "auto" is
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supported for class_weight if this is provided.
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Returns
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-------
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sample_weight_vect : ndarray, shape (n_samples,)
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Array with sample weights as applied to the original y
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"""
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y = np.atleast_1d(y)
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if y.ndim == 1:
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y = np.reshape(y, (-1, 1))
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n_outputs = y.shape[1]
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if isinstance(class_weight, string_types):
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if class_weight != 'auto':
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raise ValueError('The only valid preset for class_weight is '
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'"auto". Given "%s".' % class_weight)
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elif (indices is not None and
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not isinstance(class_weight, string_types)):
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raise ValueError('The only valid class_weight for subsampling is '
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'"auto". Given "%s".' % class_weight)
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elif n_outputs > 1:
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if (not hasattr(class_weight, "__iter__") or
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isinstance(class_weight, dict)):
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raise ValueError("For multi-output, class_weight should be a "
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"list of dicts, or a valid string.")
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if len(class_weight) != n_outputs:
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raise ValueError("For multi-output, number of elements in "
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"class_weight should match number of outputs.")
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expanded_class_weight = []
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for k in range(n_outputs):
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y_full = y[:, k]
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classes_full = np.unique(y_full)
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classes_missing = None
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if class_weight == 'auto' or n_outputs == 1:
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class_weight_k = class_weight
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else:
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class_weight_k = class_weight[k]
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if indices is not None:
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# Get class weights for the subsample, covering all classes in
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# case some labels that were present in the original data are
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# missing from the sample.
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y_subsample = y[indices, k]
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classes_subsample = np.unique(y_subsample)
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weight_k = np.choose(np.searchsorted(classes_subsample,
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classes_full),
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compute_class_weight(class_weight_k,
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classes_subsample,
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y_subsample),
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mode='clip')
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classes_missing = set(classes_full) - set(classes_subsample)
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else:
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weight_k = compute_class_weight(class_weight_k,
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classes_full,
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y_full)
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weight_k = weight_k[np.searchsorted(classes_full, y_full)]
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if classes_missing:
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# Make missing classes' weight zero
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weight_k[in1d(y_full, list(classes_missing))] = 0.
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expanded_class_weight.append(weight_k)
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expanded_class_weight = np.prod(expanded_class_weight,
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axis=0,
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dtype=np.float64)
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return expanded_class_weight
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def _assert_all_finite(X):
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"""Like assert_all_finite, but only for ndarray."""
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X = np.asanyarray(X)
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# First try an O(n) time, O(1) space solution for the common case that
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# everything is finite; fall back to O(n) space np.isfinite to prevent
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# false positives from overflow in sum method.
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if (X.dtype.char in np.typecodes['AllFloat'] and not np.isfinite(X.sum())
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and not np.isfinite(X).all()):
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raise ValueError("Input contains NaN, infinity"
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" or a value too large for %r." % X.dtype)
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def check_array(array, accept_sparse=None, dtype="numeric", order=None,
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copy=False, force_all_finite=True, ensure_2d=True,
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allow_nd=False, ensure_min_samples=1, ensure_min_features=1):
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"""Input validation on an array, list, sparse matrix or similar.
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By default, the input is converted to an at least 2nd numpy array.
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If the dtype of the array is object, attempt converting to float,
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raising on failure.
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Parameters
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----------
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array : object
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Input object to check / convert.
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accept_sparse : string, list of string or None (default=None)
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String[s] representing allowed sparse matrix formats, such as 'csc',
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'csr', etc. None means that sparse matrix input will raise an error.
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If the input is sparse but not in the allowed format, it will be
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converted to the first listed format.
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dtype : string, type or None (default="numeric")
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Data type of result. If None, the dtype of the input is preserved.
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If "numeric", dtype is preserved unless array.dtype is object.
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order : 'F', 'C' or None (default=None)
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Whether an array will be forced to be fortran or c-style.
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copy : boolean (default=False)
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Whether a forced copy will be triggered. If copy=False, a copy might
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be triggered by a conversion.
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force_all_finite : boolean (default=True)
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Whether to raise an error on np.inf and np.nan in X.
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ensure_2d : boolean (default=True)
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Whether to make X at least 2d.
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allow_nd : boolean (default=False)
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Whether to allow X.ndim > 2.
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ensure_min_samples : int (default=1)
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Make sure that the array has a minimum number of samples in its first
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axis (rows for a 2D array). Setting to 0 disables this check.
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ensure_min_features : int (default=1)
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Make sure that the 2D array has some minimum number of features
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(columns). The default value of 1 rejects empty datasets.
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This check is only enforced when the input data has effectively 2
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dimensions or is originally 1D and ``ensure_2d`` is True. Setting to 0
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disables this check.
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Returns
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-------
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X_converted : object
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The converted and validated X.
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"""
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if isinstance(accept_sparse, str):
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accept_sparse = [accept_sparse]
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# store whether originally we wanted numeric dtype
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dtype_numeric = dtype == "numeric"
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if ensure_2d:
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array = np.atleast_2d(array)
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if dtype_numeric:
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if hasattr(array, "dtype") and getattr(array.dtype, "kind", None) == "O":
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# if input is object, convert to float.
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dtype = np.float64
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else:
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dtype = None
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array = np.array(array, dtype=dtype, order=order, copy=copy)
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# make sure we actually converted to numeric:
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if dtype_numeric and array.dtype.kind == "O":
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array = array.astype(np.float64)
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if not allow_nd and array.ndim >= 3:
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raise ValueError("Found array with dim %d. Expected <= 2" %
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array.ndim)
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if force_all_finite:
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_assert_all_finite(array)
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shape_repr = _shape_repr(array.shape)
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if ensure_min_samples > 0:
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n_samples = _num_samples(array)
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if n_samples < ensure_min_samples:
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raise ValueError("Found array with %d sample(s) (shape=%s) while a"
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" minimum of %d is required."
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% (n_samples, shape_repr, ensure_min_samples))
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if ensure_min_features > 0 and array.ndim == 2:
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n_features = array.shape[1]
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if n_features < ensure_min_features:
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raise ValueError("Found array with %d feature(s) (shape=%s) while"
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" a minimum of %d is required."
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% (n_features, shape_repr, ensure_min_features))
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return array
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def check_random_state(seed):
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"""Turn seed into a np.random.RandomState instance
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If seed is None, return the RandomState singleton used by np.random.
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If seed is an int, return a new RandomState instance seeded with seed.
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If seed is already a RandomState instance, return it.
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Otherwise raise ValueError.
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"""
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if seed is None or seed is np.random:
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return np.random.mtrand._rand
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if isinstance(seed, (numbers.Integral, np.integer)):
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return np.random.RandomState(seed)
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if isinstance(seed, np.random.RandomState):
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return seed
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raise ValueError('%r cannot be used to seed a numpy.random.RandomState'
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' instance' % seed)
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def _shape_repr(shape):
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"""Return a platform independent reprensentation of an array shape
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Under Python 2, the `long` type introduces an 'L' suffix when using the
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default %r format for tuples of integers (typically used to store the shape
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of an array).
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Under Windows 64 bit (and Python 2), the `long` type is used by default
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in numpy shapes even when the integer dimensions are well below 32 bit.
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The platform specific type causes string messages or doctests to change
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from one platform to another which is not desirable.
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Under Python 3, there is no more `long` type so the `L` suffix is never
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introduced in string representation.
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>>> _shape_repr((1, 2))
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'(1, 2)'
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>>> one = 2 ** 64 / 2 ** 64 # force an upcast to `long` under Python 2
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>>> _shape_repr((one, 2 * one))
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'(1, 2)'
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>>> _shape_repr((1,))
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'(1,)'
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>>> _shape_repr(())
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'()'
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"""
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if len(shape) == 0:
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return "()"
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joined = ", ".join("%d" % e for e in shape)
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if len(shape) == 1:
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# special notation for singleton tuples
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joined += ','
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return "(%s)" % joined
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def _num_samples(x):
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"""Return number of samples in array-like x."""
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if hasattr(x, 'fit'):
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# Don't get num_samples from an ensembles length!
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raise TypeError('Expected sequence or array-like, got '
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'estimator %s' % x)
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if not hasattr(x, '__len__') and not hasattr(x, 'shape'):
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if hasattr(x, '__array__'):
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x = np.asarray(x)
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else:
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raise TypeError("Expected sequence or array-like, got %s" %
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type(x))
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if hasattr(x, 'shape'):
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if len(x.shape) == 0:
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raise TypeError("Singleton array %r cannot be considered"
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" a valid collection." % x)
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return x.shape[0]
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else:
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return len(x)
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################################ metrics ########################################
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def _weighted_sum(sample_score, sample_weight, normalize=False):
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if normalize:
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return np.average(sample_score, weights=sample_weight)
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elif sample_weight is not None:
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return np.dot(sample_score, sample_weight)
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else:
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return sample_score.sum()
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def accuracy_score(y_true, y_pred, normalize=True, sample_weight=None):
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"""Accuracy classification score.
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In multilabel classification, this function computes subset accuracy:
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the set of labels predicted for a sample must *exactly* match the
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corresponding set of labels in y_true.
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Parameters
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----------
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y_true : 1d array-like, or label indicator array / sparse matrix
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Ground truth (correct) labels.
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y_pred : 1d array-like, or label indicator array / sparse matrix
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Predicted labels, as returned by a classifier.
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normalize : bool, optional (default=True)
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If ``False``, return the number of correctly classified samples.
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Otherwise, return the fraction of correctly classified samples.
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sample_weight : array-like of shape = [n_samples], optional
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Sample weights.
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Returns
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-------
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score : float
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If ``normalize == True``, return the correctly classified samples
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(float), else it returns the number of correctly classified samples
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(int).
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The best performance is 1 with ``normalize == True`` and the number
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of samples with ``normalize == False``.
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See also
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--------
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jaccard_similarity_score, hamming_loss, zero_one_loss
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Notes
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-----
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In binary and multiclass classification, this function is equal
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to the ``jaccard_similarity_score`` function.
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Examples
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--------
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>>> import numpy as np
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>>> from sklearn.metrics import accuracy_score
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>>> y_pred = [0, 2, 1, 3]
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>>> y_true = [0, 1, 2, 3]
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>>> accuracy_score(y_true, y_pred)
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0.5
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>>> accuracy_score(y_true, y_pred, normalize=False)
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2
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In the multilabel case with binary label indicators:
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>>> accuracy_score(np.array([[0, 1], [1, 1]]), np.ones((2, 2)))
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0.5
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"""
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# Compute accuracy for each possible representation
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y_type, y_true, y_pred = _check_targets(y_true, y_pred)
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if y_type.startswith('multilabel'):
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differing_labels = count_nonzero(y_true - y_pred, axis=1)
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score = differing_labels == 0
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else:
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score = y_true == y_pred
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return _weighted_sum(score, sample_weight, normalize)
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|
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def r2_score(y_true, y_pred, sample_weight=None):
|
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"""R^2 (coefficient of determination) regression score function.
|
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|
||||
Best possible score is 1.0, lower values are worse.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
y_true : array-like of shape = [n_samples] or [n_samples, n_outputs]
|
||||
Ground truth (correct) target values.
|
||||
|
||||
y_pred : array-like of shape = [n_samples] or [n_samples, n_outputs]
|
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Estimated target values.
|
||||
|
||||
sample_weight : array-like of shape = [n_samples], optional
|
||||
Sample weights.
|
||||
|
||||
Returns
|
||||
-------
|
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z : float
|
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The R^2 score.
|
||||
|
||||
Notes
|
||||
-----
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||||
This is not a symmetric function.
|
||||
|
||||
Unlike most other scores, R^2 score may be negative (it need not actually
|
||||
be the square of a quantity R).
|
||||
|
||||
References
|
||||
----------
|
||||
.. [1] `Wikipedia entry on the Coefficient of determination
|
||||
<http://en.wikipedia.org/wiki/Coefficient_of_determination>`_
|
||||
|
||||
Examples
|
||||
--------
|
||||
>>> from sklearn.metrics import r2_score
|
||||
>>> y_true = [3, -0.5, 2, 7]
|
||||
>>> y_pred = [2.5, 0.0, 2, 8]
|
||||
>>> r2_score(y_true, y_pred) # doctest: +ELLIPSIS
|
||||
0.948...
|
||||
>>> y_true = [[0.5, 1], [-1, 1], [7, -6]]
|
||||
>>> y_pred = [[0, 2], [-1, 2], [8, -5]]
|
||||
>>> r2_score(y_true, y_pred) # doctest: +ELLIPSIS
|
||||
0.938...
|
||||
|
||||
"""
|
||||
y_type, y_true, y_pred = _check_reg_targets(y_true, y_pred)
|
||||
|
||||
if sample_weight is not None:
|
||||
sample_weight = column_or_1d(sample_weight)
|
||||
weight = sample_weight[:, np.newaxis]
|
||||
else:
|
||||
weight = 1.
|
||||
|
||||
numerator = (weight * (y_true - y_pred) ** 2).sum(dtype=np.float64)
|
||||
denominator = (weight * (y_true - np.average(
|
||||
y_true, axis=0, weights=sample_weight)) ** 2).sum(dtype=np.float64)
|
||||
|
||||
if denominator == 0.0:
|
||||
if numerator == 0.0:
|
||||
return 1.0
|
||||
else:
|
||||
# arbitrary set to zero to avoid -inf scores, having a constant
|
||||
# y_true is not interesting for scoring a regression anyway
|
||||
return 0.0
|
||||
|
||||
return 1 - numerator / denominator
|
||||
|
||||
|
||||
################################ base #########################################
|
||||
###############################################################################
|
||||
|
||||
|
||||
class BaseEstimator(object):
|
||||
"""Base class for all estimators in scikit-learn
|
||||
|
||||
Notes
|
||||
-----
|
||||
All estimators should specify all the parameters that can be set
|
||||
at the class level in their ``__init__`` as explicit keyword
|
||||
arguments (no ``*args`` or ``**kwargs``).
|
||||
"""
|
||||
|
||||
@classmethod
|
||||
def _get_param_names(cls):
|
||||
"""Get parameter names for the estimator"""
|
||||
# fetch the constructor or the original constructor before
|
||||
# deprecation wrapping if any
|
||||
init = getattr(cls.__init__, 'deprecated_original', cls.__init__)
|
||||
if init is object.__init__:
|
||||
# No explicit constructor to introspect
|
||||
return []
|
||||
|
||||
# introspect the constructor arguments to find the model parameters
|
||||
# to represent
|
||||
args, varargs, kw, default = inspect.getargspec(init)
|
||||
if varargs is not None:
|
||||
raise RuntimeError("scikit-learn estimators should always "
|
||||
"specify their parameters in the signature"
|
||||
" of their __init__ (no varargs)."
|
||||
" %s doesn't follow this convention."
|
||||
% (cls, ))
|
||||
# Remove 'self'
|
||||
# XXX: This is going to fail if the init is a staticmethod, but
|
||||
# who would do this?
|
||||
args.pop(0)
|
||||
args.sort()
|
||||
return args
|
||||
|
||||
def get_params(self, deep=True):
|
||||
"""Get parameters for this estimator.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
deep: boolean, optional
|
||||
If True, will return the parameters for this estimator and
|
||||
contained subobjects that are estimators.
|
||||
|
||||
Returns
|
||||
-------
|
||||
params : mapping of string to any
|
||||
Parameter names mapped to their values.
|
||||
"""
|
||||
out = dict()
|
||||
for key in self._get_param_names():
|
||||
# We need deprecation warnings to always be on in order to
|
||||
# catch deprecated param values.
|
||||
# This is set in utils/__init__.py but it gets overwritten
|
||||
# when running under python3 somehow.
|
||||
warnings.simplefilter("always", DeprecationWarning)
|
||||
try:
|
||||
with warnings.catch_warnings(record=True) as w:
|
||||
value = getattr(self, key, None)
|
||||
if len(w) and w[0].category == DeprecationWarning:
|
||||
# if the parameter is deprecated, don't show it
|
||||
continue
|
||||
finally:
|
||||
warnings.filters.pop(0)
|
||||
|
||||
# XXX: should we rather test if instance of estimator?
|
||||
if deep and hasattr(value, 'get_params'):
|
||||
deep_items = value.get_params().items()
|
||||
out.update((key + '__' + k, val) for k, val in deep_items)
|
||||
out[key] = value
|
||||
return out
|
||||
|
||||
def set_params(self, **params):
|
||||
"""Set the parameters of this estimator.
|
||||
|
||||
The method works on simple estimators as well as on nested objects
|
||||
(such as pipelines). The former have parameters of the form
|
||||
``<component>__<parameter>`` so that it's possible to update each
|
||||
component of a nested object.
|
||||
|
||||
Returns
|
||||
-------
|
||||
self
|
||||
"""
|
||||
if not params:
|
||||
# Simple optimisation to gain speed (inspect is slow)
|
||||
return self
|
||||
valid_params = self.get_params(deep=True)
|
||||
for key, value in iteritems(params):
|
||||
split = key.split('__', 1)
|
||||
if len(split) > 1:
|
||||
# nested objects case
|
||||
name, sub_name = split
|
||||
if not name in valid_params:
|
||||
raise ValueError('Invalid parameter %s for estimator %s' %
|
||||
(name, self))
|
||||
sub_object = valid_params[name]
|
||||
sub_object.set_params(**{sub_name: value})
|
||||
else:
|
||||
# simple objects case
|
||||
if not key in valid_params:
|
||||
raise ValueError('Invalid parameter %s ' 'for estimator %s'
|
||||
% (key, self.__class__.__name__))
|
||||
setattr(self, key, value)
|
||||
return self
|
||||
|
||||
def __repr__(self):
|
||||
class_name = self.__class__.__name__
|
||||
return '%s(%s)' % (class_name, _pprint(self.get_params(deep=False),
|
||||
offset=len(class_name),),)
|
||||
|
||||
class MetaEstimatorMixin(object):
|
||||
"""Mixin class for all meta estimators in scikit-learn."""
|
||||
# this is just a tag for the moment
|
||||
|
||||
|
||||
class ClassifierMixin(object):
|
||||
"""Mixin class for all classifiers in scikit-learn."""
|
||||
|
||||
def score(self, X, y, sample_weight=None):
|
||||
"""Returns the mean accuracy on the given test data and labels.
|
||||
|
||||
In multi-label classification, this is the subset accuracy
|
||||
which is a harsh metric since you require for each sample that
|
||||
each label set be correctly predicted.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
X : array-like, shape = (n_samples, n_features)
|
||||
Test samples.
|
||||
|
||||
y : array-like, shape = (n_samples) or (n_samples, n_outputs)
|
||||
True labels for X.
|
||||
|
||||
sample_weight : array-like, shape = [n_samples], optional
|
||||
Sample weights.
|
||||
|
||||
Returns
|
||||
-------
|
||||
score : float
|
||||
Mean accuracy of self.predict(X) wrt. y.
|
||||
|
||||
"""
|
||||
return accuracy_score(y, self.predict(X), sample_weight=sample_weight)
|
||||
|
||||
class RegressorMixin(object):
|
||||
"""Mixin class for all regression estimators in scikit-learn."""
|
||||
|
||||
def score(self, X, y, sample_weight=None):
|
||||
"""Returns the coefficient of determination R^2 of the prediction.
|
||||
|
||||
The coefficient R^2 is defined as (1 - u/v), where u is the regression
|
||||
sum of squares ((y_true - y_pred) ** 2).sum() and v is the residual
|
||||
sum of squares ((y_true - y_true.mean()) ** 2).sum().
|
||||
Best possible score is 1.0, lower values are worse.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
X : array-like, shape = (n_samples, n_features)
|
||||
Test samples.
|
||||
|
||||
y : array-like, shape = (n_samples) or (n_samples, n_outputs)
|
||||
True values for X.
|
||||
|
||||
sample_weight : array-like, shape = [n_samples], optional
|
||||
Sample weights.
|
||||
|
||||
Returns
|
||||
-------
|
||||
score : float
|
||||
R^2 of self.predict(X) wrt. y.
|
||||
"""
|
||||
return r2_score(y, self.predict(X), sample_weight=sample_weight)
|
||||
|
||||
######################### Preprocessing ################################
|
||||
|
||||
class OneHotEncoder:
|
||||
"""Encode categorical integer features using a one-hot aka one-of-K scheme.
|
||||
|
||||
The input to this transformer should be a matrix of integers, denoting
|
||||
the values taken on by categorical (discrete) features. The output will be
|
||||
a sparse matrix where each column corresponds to one possible value of one
|
||||
feature. It is assumed that input features take on values in the range
|
||||
[0, n_values).
|
||||
|
||||
This encoding is needed for feeding categorical data to many scikit-learn
|
||||
estimators, notably linear models and SVMs with the standard kernels.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
n_values : 'auto', int or array of ints
|
||||
Number of values per feature.
|
||||
|
||||
- 'auto' : determine value range from training data.
|
||||
- int : maximum value for all features.
|
||||
- array : maximum value per feature.
|
||||
|
||||
categorical_features: "all" or array of indices or mask
|
||||
Specify what features are treated as categorical.
|
||||
|
||||
- 'all' (default): All features are treated as categorical.
|
||||
- array of indices: Array of categorical feature indices.
|
||||
- mask: Array of length n_features and with dtype=bool.
|
||||
|
||||
Non-categorical features are always stacked to the right of the matrix.
|
||||
|
||||
dtype : number type, default=np.float
|
||||
Desired dtype of output.
|
||||
|
||||
sparse : boolean, default=True
|
||||
Will return sparse matrix if set True else will return an array.
|
||||
|
||||
handle_unknown : str, 'error' or 'ignore'
|
||||
Whether to raise an error or ignore if a unknown categorical feature is
|
||||
present during transform.
|
||||
|
||||
Attributes
|
||||
----------
|
||||
active_features_ : array
|
||||
Indices for active features, meaning values that actually occur
|
||||
in the training set. Only available when n_values is ``'auto'``.
|
||||
|
||||
feature_indices_ : array of shape (n_features,)
|
||||
Indices to feature ranges.
|
||||
Feature ``i`` in the original data is mapped to features
|
||||
from ``feature_indices_[i]`` to ``feature_indices_[i+1]``
|
||||
(and then potentially masked by `active_features_` afterwards)
|
||||
|
||||
n_values_ : array of shape (n_features,)
|
||||
Maximum number of values per feature.
|
||||
|
||||
Examples
|
||||
--------
|
||||
Given a dataset with three features and two samples, we let the encoder
|
||||
find the maximum value per feature and transform the data to a binary
|
||||
one-hot encoding.
|
||||
|
||||
>>> from sklearn.preprocessing import OneHotEncoder
|
||||
>>> enc = OneHotEncoder()
|
||||
>>> enc.fit([[0, 0, 3], [1, 1, 0], [0, 2, 1], \
|
||||
[1, 0, 2]]) # doctest: +ELLIPSIS
|
||||
OneHotEncoder(categorical_features='all', dtype=<... 'float'>,
|
||||
handle_unknown='error', n_values='auto', sparse=True)
|
||||
>>> enc.n_values_
|
||||
array([2, 3, 4])
|
||||
>>> enc.feature_indices_
|
||||
array([0, 2, 5, 9])
|
||||
>>> enc.transform([[0, 1, 1]]).toarray()
|
||||
array([[ 1., 0., 0., 1., 0., 0., 1., 0., 0.]])
|
||||
|
||||
See also
|
||||
--------
|
||||
sklearn.feature_extraction.DictVectorizer : performs a one-hot encoding of
|
||||
dictionary items (also handles string-valued features).
|
||||
sklearn.feature_extraction.FeatureHasher : performs an approximate one-hot
|
||||
encoding of dictionary items or strings.
|
||||
"""
|
||||
def __init__(self, n_values="auto", categorical_features="all",
|
||||
dtype=np.float, sparse=True, handle_unknown='error'):
|
||||
self.n_values = n_values
|
||||
self.categorical_features = categorical_features
|
||||
self.dtype = dtype
|
||||
self.sparse = sparse
|
||||
self.handle_unknown = handle_unknown
|
||||
|
||||
def fit(self, X, y=None):
|
||||
"""Fit OneHotEncoder to X.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
X : array-like, shape=(n_samples, n_feature)
|
||||
Input array of type int.
|
||||
|
||||
Returns
|
||||
-------
|
||||
self
|
||||
"""
|
||||
self.fit_transform(X)
|
||||
return self
|
||||
|
||||
def _fit_transform(self, X):
|
||||
"""Assumes X contains only categorical features."""
|
||||
X = check_array(X, dtype=np.int)
|
||||
if np.any(X < 0):
|
||||
raise ValueError("X needs to contain only non-negative integers.")
|
||||
n_samples, n_features = X.shape
|
||||
if self.n_values == 'auto':
|
||||
n_values = np.max(X, axis=0) + 1
|
||||
elif isinstance(self.n_values, numbers.Integral):
|
||||
if (np.max(X, axis=0) >= self.n_values).any():
|
||||
raise ValueError("Feature out of bounds for n_values=%d"
|
||||
% self.n_values)
|
||||
n_values = np.empty(n_features, dtype=np.int)
|
||||
n_values.fill(self.n_values)
|
||||
else:
|
||||
try:
|
||||
n_values = np.asarray(self.n_values, dtype=int)
|
||||
except (ValueError, TypeError):
|
||||
raise TypeError("Wrong type for parameter `n_values`. Expected"
|
||||
" 'auto', int or array of ints, got %r"
|
||||
% type(X))
|
||||
if n_values.ndim < 1 or n_values.shape[0] != X.shape[1]:
|
||||
raise ValueError("Shape mismatch: if n_values is an array,"
|
||||
" it has to be of shape (n_features,).")
|
||||
|
||||
self.n_values_ = n_values
|
||||
n_values = np.hstack([[0], n_values])
|
||||
indices = np.cumsum(n_values)
|
||||
self.feature_indices_ = indices
|
||||
|
||||
column_indices = (X + indices[:-1]).ravel()
|
||||
row_indices = np.repeat(np.arange(n_samples, dtype=np.int32),
|
||||
n_features)
|
||||
#data = np.ones(n_samples * n_features)
|
||||
#out = sparse.coo_matrix((data, (row_indices, column_indices)),
|
||||
# shape=(n_samples, indices[-1]),
|
||||
# dtype=self.dtype).tocsr()
|
||||
data = np.zeros(n_samples, indices[-1], dtype = self.dtype)
|
||||
data[row_indices, column_indices] = 1
|
||||
|
||||
print out
|
||||
|
||||
if self.n_values == 'auto':
|
||||
mask = np.array(out.sum(axis=0)).ravel() != 0
|
||||
active_features = np.where(mask)[0]
|
||||
out = out[:, active_features]
|
||||
self.active_features_ = active_features
|
||||
|
||||
return out if self.sparse else out.toarray()
|
||||
|
||||
def fit_transform(self, X, y=None):
|
||||
"""Fit OneHotEncoder to X, then transform X.
|
||||
|
||||
Equivalent to self.fit(X).transform(X), but more convenient and more
|
||||
efficient. See fit for the parameters, transform for the return value.
|
||||
"""
|
||||
return _transform_selected(X, self._fit_transform,
|
||||
self.categorical_features, copy=True)
|
||||
|
||||
def _transform(self, X):
|
||||
"""Assumes X contains only categorical features."""
|
||||
X = check_array(X, dtype=np.int)
|
||||
if np.any(X < 0):
|
||||
raise ValueError("X needs to contain only non-negative integers.")
|
||||
n_samples, n_features = X.shape
|
||||
|
||||
indices = self.feature_indices_
|
||||
if n_features != indices.shape[0] - 1:
|
||||
raise ValueError("X has different shape than during fitting."
|
||||
" Expected %d, got %d."
|
||||
% (indices.shape[0] - 1, n_features))
|
||||
|
||||
# We use only those catgorical features of X that are known using fit.
|
||||
# i.e lesser than n_values_ using mask.
|
||||
# This means, if self.handle_unknown is "ignore", the row_indices and
|
||||
# col_indices corresponding to the unknown categorical feature are
|
||||
# ignored.
|
||||
mask = (X < self.n_values_).ravel()
|
||||
if np.any(~mask):
|
||||
if self.handle_unknown not in ['error', 'ignore']:
|
||||
raise ValueError("handle_unknown should be either error or "
|
||||
"unknown got %s" % self.handle_unknown)
|
||||
if self.handle_unknown == 'error':
|
||||
raise ValueError("unknown categorical feature present %s "
|
||||
"during transform." % X[~mask])
|
||||
|
||||
column_indices = (X + indices[:-1]).ravel()[mask]
|
||||
row_indices = np.repeat(np.arange(n_samples, dtype=np.int32),
|
||||
n_features)[mask]
|
||||
data = np.ones(np.sum(mask))
|
||||
out = sparse.coo_matrix((data, (row_indices, column_indices)),
|
||||
shape=(n_samples, indices[-1]),
|
||||
dtype=self.dtype).tocsr()
|
||||
if self.n_values == 'auto':
|
||||
out = out[:, self.active_features_]
|
||||
|
||||
return out if self.sparse else out.toarray()
|
||||
|
||||
def transform(self, X):
|
||||
"""Transform X using one-hot encoding.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
X : array-like, shape=(n_samples, n_features)
|
||||
Input array of type int.
|
||||
|
||||
Returns
|
||||
-------
|
||||
X_out : sparse matrix if sparse=True else a 2-d array, dtype=int
|
||||
Transformed input.
|
||||
"""
|
||||
return _transform_selected(X, self._transform,
|
||||
self.categorical_features, copy=True)
|
Reference in New Issue
Block a user