sklearn.decomposition.dict_learning_online¶
- sklearn.decomposition.dict_learning_online(X, n_components=2, alpha=1, n_iter=100, return_code=True, dict_init=None, callback=None, batch_size=3, verbose=False, shuffle=True, n_jobs=1, method='lars', iter_offset=0, random_state=None)¶
Solves a dictionary learning matrix factorization problem online.
Finds the best dictionary and the corresponding sparse code for approximating the data matrix X by solving:
(U^*, V^*) = argmin 0.5 || X - U V ||_2^2 + alpha * || U ||_1 (U,V) with || V_k ||_2 = 1 for all 0 <= k < n_components
where V is the dictionary and U is the sparse code. This is accomplished by repeatedly iterating over mini-batches by slicing the input data.
Parameters : X: array of shape (n_samples, n_features) :
Data matrix.
n_components : int,
Number of dictionary atoms to extract.
alpha : int,
Sparsity controlling parameter.
n_iter : int,
Number of iterations to perform.
return_code : boolean,
Whether to also return the code U or just the dictionary V.
dict_init : array of shape (n_components, n_features),
Initial value for the dictionary for warm restart scenarios.
callback : :
Callable that gets invoked every five iterations.
batch_size : int,
The number of samples to take in each batch.
verbose : :
Degree of output the procedure will print.
shuffle : boolean,
Whether to shuffle the data before splitting it in batches.
n_jobs : int,
Number of parallel jobs to run, or -1 to autodetect.
method : {‘lars’, ‘cd’}
lars: uses the least angle regression method to solve the lasso problem (linear_model.lars_path) cd: uses the coordinate descent method to compute the Lasso solution (linear_model.Lasso). Lars will be faster if the estimated components are sparse.
iter_offset : int, default 0
Number of previous iterations completed on the dictionary used for initialization.
random_state : int or RandomState
Pseudo number generator state used for random sampling.
Returns : code : array of shape (n_samples, n_components),
the sparse code (only returned if return_code=True)
dictionary : array of shape (n_components, n_features),
the solutions to the dictionary learning problem