[MRG+1] DOC improve description and consistency of random_state (scik…

…it-learn#8689)

* DOC improve description of random_state in train_test_split

* DOC Make random_state consistent through documentation

* FIX reverse doc mistake

* FIX address comment of Tom

* DOC address comments

* DOC remove empty line

* DOC remove unecessary white spaces

sklearn/cluster/bicluster.py

@@ -236,9 +236,11 @@ class SpectralCoclustering(BaseSpectral):
         (n_cpus + 1 + n_jobs) are used. Thus for n_jobs = -2, all CPUs but one
         are used.
 
-    random_state : int seed, RandomState instance, or None (default)
-        A pseudo random number generator used by the K-Means
-        initialization.
+    random_state : int, RandomState instance or None, optional, default: None
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     Attributes
     ----------
@@ -366,9 +368,11 @@ class SpectralBiclustering(BaseSpectral):
         (n_cpus + 1 + n_jobs) are used. Thus for n_jobs = -2, all CPUs but one
         are used.
 
-    random_state : int seed, RandomState instance, or None (default)
-        A pseudo random number generator used by the K-Means
-        initialization.
+    random_state : int, RandomState instance or None, optional, default: None
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     Attributes
     ----------

sklearn/cluster/k_means_.py

@@ -230,10 +230,11 @@ def k_means(X, n_clusters, init='k-means++', precompute_distances='auto',
     verbose : boolean, optional
         Verbosity mode.
 
-    random_state : integer or numpy.RandomState, optional
-        The generator used to initialize the centers. If an integer is
-        given, it fixes the seed. Defaults to the global numpy random
-        number generator.
+    random_state : int, RandomState instance or None, optional, default: None
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     copy_x : boolean, optional
         When pre-computing distances it is more numerically accurate to center
@@ -449,10 +450,11 @@ def _kmeans_single_lloyd(X, n_clusters, max_iter=300, init='k-means++',
     precompute_distances : boolean, default: True
         Precompute distances (faster but takes more memory).
 
-    random_state : integer or numpy.RandomState, optional
-        The generator used to initialize the centers. If an integer is
-        given, it fixes the seed. Defaults to the global numpy random
-        number generator.
+    random_state : int, RandomState instance or None, optional, default: None
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     Returns
     -------
@@ -638,10 +640,11 @@ def _init_centroids(X, k, init, random_state=None, x_squared_norms=None,
     init : {'k-means++', 'random' or ndarray or callable} optional
         Method for initialization
 
-    random_state : integer or numpy.RandomState, optional
-        The generator used to initialize the centers. If an integer is
-        given, it fixes the seed. Defaults to the global numpy random
-        number generator.
+    random_state : int, RandomState instance or None, optional, default: None
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     x_squared_norms :  array, shape (n_samples,), optional
         Squared euclidean norm of each data point. Pass it if you have it at
@@ -766,10 +769,11 @@ class KMeans(BaseEstimator, ClusterMixin, TransformerMixin):
         (n_cpus + 1 + n_jobs) are used. Thus for n_jobs = -2, all CPUs but one
         are used.
 
-    random_state : integer or numpy.RandomState, optional
-        The generator used to initialize the centers. If an integer is
-        given, it fixes the seed. Defaults to the global numpy random
-        number generator.
+    random_state : int, RandomState instance or None, optional, default: None
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     verbose : int, default 0
         Verbosity mode.
@@ -1008,10 +1012,11 @@ def _mini_batch_step(X, x_squared_norms, centers, counts,
         the distances of each sample to its closest center.
         May not be None when random_reassign is True.
 
-    random_state : integer or numpy.RandomState, optional
-        The generator used to initialize the centers. If an integer is
-        given, it fixes the seed. Defaults to the global numpy random
-        number generator.
+    random_state : int, RandomState instance or None, optional, default: None
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     random_reassign : boolean, optional
         If True, centers with very low counts are randomly reassigned
@@ -1247,10 +1252,11 @@ class MiniBatchKMeans(KMeans):
         Compute label assignment and inertia for the complete dataset
         once the minibatch optimization has converged in fit.
 
-    random_state : integer or numpy.RandomState, optional
-        The generator used to initialize the centers. If an integer is
-        given, it fixes the seed. Defaults to the global numpy random
-        number generator.
+    random_state : int, RandomState instance or None, optional, default: None
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     reassignment_ratio : float, default: 0.01
         Control the fraction of the maximum number of counts for a

sklearn/cluster/mean_shift_.py

@@ -47,8 +47,11 @@ def estimate_bandwidth(X, quantile=0.3, n_samples=None, random_state=0,
     n_samples : int, optional
         The number of samples to use. If not given, all samples are used.
 
-    random_state : int or RandomState
-        Pseudo-random number generator state used for random sampling.
+    random_state : int, RandomState instance or None, optional (default=None)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     n_jobs : int, optional (default = 1)
         The number of parallel jobs to run for neighbors search.

sklearn/cluster/spectral.py

@@ -39,9 +39,11 @@ def discretize(vectors, copy=True, max_svd_restarts=30, n_iter_max=20,
         Maximum number of iterations to attempt in rotation and partition
         matrix search if machine precision convergence is not reached
 
-    random_state : int seed, RandomState instance, or None (default)
-        A pseudo random number generator used for the initialization of the
-        of the rotation matrix
+    random_state : int, RandomState instance or None, optional, default: None
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     Returns
     -------
@@ -194,10 +196,13 @@ def spectral_clustering(affinity, n_clusters=8, n_components=None,
         to be installed. It can be faster on very large, sparse problems,
         but may also lead to instabilities
 
-    random_state : int seed, RandomState instance, or None (default)
-        A pseudo random number generator used for the initialization
-        of the lobpcg eigen vectors decomposition when eigen_solver == 'amg'
-        and by the K-Means initialization.
+    random_state : int, RandomState instance or None, optional, default: None
+        A pseudo random number generator used for the initialization of the
+        lobpcg eigen vectors decomposition when eigen_solver == 'amg' and by
+        the K-Means initialization. If int, random_state is the seed used by
+        the random number generator; If RandomState instance, random_state is
+        the random number generator; If None, the random number generator is
+        the RandomState instance used by `np.random`.
 
     n_init : int, optional, default: 10
         Number of time the k-means algorithm will be run with different
@@ -326,10 +331,13 @@ class SpectralClustering(BaseEstimator, ClusterMixin):
         to be installed. It can be faster on very large, sparse problems,
         but may also lead to instabilities
 
-    random_state : int seed, RandomState instance, or None (default)
-        A pseudo random number generator used for the initialization
-        of the lobpcg eigen vectors decomposition when eigen_solver == 'amg'
-        and by the K-Means initialization.
+    random_state : int, RandomState instance or None, optional, default: None
+        A pseudo random number generator used for the initialization of the
+        lobpcg eigen vectors decomposition when eigen_solver == 'amg' and by
+        the K-Means initialization.  If int, random_state is the seed used by
+        the random number generator; If RandomState instance, random_state is
+        the random number generator; If None, the random number generator is
+        the RandomState instance used by `np.random`.
 
     n_init : int, optional, default: 10
         Number of time the k-means algorithm will be run with different

sklearn/covariance/robust_covariance.py

@@ -55,9 +55,11 @@ def c_step(X, n_support, remaining_iterations=30, initial_estimates=None,
     verbose : boolean, optional
         Verbose mode.
 
-    random_state : integer or numpy.RandomState, optional
-        The random generator used. If an integer is given, it fixes the
-        seed. Defaults to the global numpy random number generator.
+    random_state : int, RandomState instance or None, optional (default=None)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     cov_computation_method : callable, default empirical_covariance
         The function which will be used to compute the covariance.
@@ -214,9 +216,11 @@ def select_candidates(X, n_support, n_trials, select=1, n_iter=30,
         Maximum number of iterations for the c_step procedure.
         (2 is enough to be close to the final solution. "Never" exceeds 20).
 
-    random_state : integer or numpy.RandomState, default None
-        The random generator used. If an integer is given, it fixes the
-        seed. Defaults to the global numpy random number generator.
+    random_state : int, RandomState instance or None, optional (default=None)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     cov_computation_method : callable, default empirical_covariance
         The function which will be used to compute the covariance.
@@ -311,10 +315,11 @@ def fast_mcd(X, support_fraction=None,
           value of support_fraction will be used within the algorithm:
           `[n_sample + n_features + 1] / 2`.
 
-    random_state : integer or numpy.RandomState, optional
-        The generator used to randomly subsample. If an integer is
-        given, it fixes the seed. Defaults to the global numpy random
-        number generator.
+    random_state : int, RandomState instance or None, optional (default=None)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     cov_computation_method : callable, default empirical_covariance
         The function which will be used to compute the covariance.
@@ -531,9 +536,11 @@ class MinCovDet(EmpiricalCovariance):
         value of support_fraction will be used within the algorithm:
         [n_sample + n_features + 1] / 2
 
-    random_state : integer or numpy.RandomState, optional
-        The random generator used. If an integer is given, it fixes the
-        seed. Defaults to the global numpy random number generator.
+    random_state : int, RandomState instance or None, optional (default=None)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     Attributes
     ----------

sklearn/cross_validation.py

@@ -1,4 +1,3 @@
-
 """
 The :mod:`sklearn.cross_validation` module includes utilities for cross-
 validation and performance evaluation.
@@ -297,9 +296,11 @@ class KFold(_BaseKFold):
     shuffle : boolean, optional
         Whether to shuffle the data before splitting into batches.
 
-    random_state : None, int or RandomState
-        When shuffle=True, pseudo-random number generator state used for
-        shuffling. If None, use default numpy RNG for shuffling.
+    random_state : int, RandomState instance or None, optional, default=None
+        If int, random_state is the seed used by the random number
+        generator; If RandomState instance, random_state is the random number
+        generator; If None, the random number generator is the RandomState
+        instance used by `np.random`. Used when ``shuffle`` == True.
 
     Examples
     --------
@@ -499,9 +500,11 @@ class StratifiedKFold(_BaseKFold):
         Whether to shuffle each stratification of the data before splitting
         into batches.
 
-    random_state : None, int or RandomState
-        When shuffle=True, pseudo-random number generator state used for
-        shuffling. If None, use default numpy RNG for shuffling.
+    random_state : int, RandomState instance or None, optional, default=None
+        If int, random_state is the seed used by the random number
+        generator; If RandomState instance, random_state is the random number
+        generator; If None, the random number generator is the RandomState
+        instance used by `np.random`. Used when ``shuffle`` == True.
 
     Examples
     --------
@@ -822,8 +825,11 @@ class ShuffleSplit(BaseShuffleSplit):
         int, represents the absolute number of train samples. If None,
         the value is automatically set to the complement of the test size.
 
-    random_state : int or RandomState
-        Pseudo-random number generator state used for random sampling.
+    random_state : int, RandomState instance or None, optional (default None)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     Examples
     --------
@@ -1031,8 +1037,11 @@ class StratifiedShuffleSplit(BaseShuffleSplit):
         int, represents the absolute number of train samples. If None,
         the value is automatically set to the complement of the test size.
 
-    random_state : int or RandomState
-        Pseudo-random number generator state used for random sampling.
+    random_state : int, RandomState instance or None, optional (default None)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     Examples
     --------
@@ -1225,8 +1234,11 @@ class LabelShuffleSplit(ShuffleSplit):
         int, represents the absolute number of train labels. If None,
         the value is automatically set to the complement of the test size.
 
-    random_state : int or RandomState
-        Pseudo-random number generator state used for random sampling.
+    random_state : int, RandomState instance or None, optional (default None)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     """
     def __init__(self, labels, n_iter=5, test_size=0.2, train_size=None,
@@ -1889,9 +1901,11 @@ def permutation_test_score(estimator, X, y, cv=None,
         Labels constrain the permutation among groups of samples with
         a same label.
 
-    random_state : RandomState or an int seed (0 by default)
-        A random number generator instance to define the state of the
-        random permutations generator.
+    random_state : int, RandomState instance or None, optional (default=0)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     verbose : integer, optional
         The verbosity level.
@@ -1977,8 +1991,11 @@ def train_test_split(*arrays, **options):
         int, represents the absolute number of train samples. If None,
         the value is automatically set to the complement of the test size.
 
-    random_state : int or RandomState
-        Pseudo-random number generator state used for random sampling.
+    random_state : int, RandomState instance or None, optional (default=None)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     stratify : array-like or None (default is None)
         If not None, data is split in a stratified fashion, using this as

sklearn/datasets/olivetti_faces.py

@@ -71,9 +71,11 @@ def fetch_olivetti_faces(data_home=None, shuffle=False, random_state=0,
         If False, raise a IOError if the data is not locally available
         instead of trying to download the data from the source site.
 
-    random_state : optional, integer or RandomState object
-        The seed or the random number generator used to shuffle the
-        data.
+    random_state : int, RandomState instance or None, optional (default=0)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     Returns
     -------

sklearn/datasets/samples_generator.py

@@ -1059,8 +1059,11 @@ def make_sparse_coded_signal(n_samples, n_components, n_features,
     n_nonzero_coefs : int
         number of active (non-zero) coefficients in each sample
 
-    random_state : int or RandomState instance, optional (default=None)
-        seed used by the pseudo random number generator
+    random_state : int, RandomState instance or None, optional (default=None)
+        If int, random_state is the seed used by the random number generator;
+        If RandomState instance, random_state is the random number generator;
+        If None, the random number generator is the RandomState instance used
+        by `np.random`.
 
     Returns
     -------