class sklearn.kernel_approximation.Nystroem(kernel='rbf', gamma=None, coef0=1, degree=3, kernel_params=None, n_components=100
class sklearn.kernel_approximation.RBFSampler(gamma=1.0, n_components=100, random_state=None)
class sklearn.kernel_approximation.AdditiveChi2Sampler(sample_steps=2, sample_interval=None)
class sklearn.kernel_approximation.SkewedChi2Sampler(skewedness=1.0, n_components=100, random_state=None)