scipy tutorial - Baustatik-Info-Server

class dok_matrix(arg1, shape=None, dtype=None, copy=False)
Dictionary Of Keys based sparse matrix.
This is an efficient structure for constructing sparse matrices incrementally.
This can be instatiated in several ways:
Notes
dok_matrix(D)
with a dense matrix, D
dok_matrix(S)
with a sparse matrix, S
SciPy Reference Guide, Release 0.8.dev
dok_matrix((M,N), [dtype])
create the matrix with initial shape (M,N) dtype is optional, defaulting to dtype=’d’
Allows for efficient O(1) access of individual elements. Duplicates are not allowed. Can be efficiently converted
to a coo_matrix once constructed.
Examples
>>> from scipy.sparse import *
>>> from scipy import *
>>> S = dok_matrix((5,5), dtype=float32)
>>> for i in range(5):
>>> for j in range(5):
>>> S[i,j] = i+j # Update element
Methods
asformat(format) Return this matrix in a given sparse format
asfptype() Upcast matrix to a floating point format (if necessary)
astype(t)
clear D.clear() -> None. Remove all items from D.
conj()
conjtransp() Return the conjugate transpose
conjugate()
copy()
diagonal() Returns the main diagonal of the matrix
dot(*args, **kwds) dot is deprecated!
fromkeys
get(key[, default]) This overrides the dict.get method, providing type checking
getH()
get_shape()
getcol(j) Returns a copy of column j of the matrix, as an (m x 1) sparse
getdata(*args, **kwds) getdata is deprecated!
getformat()
getmaxprint()
getnnz()
getrow(i) Returns a copy of row i of the matrix, as a (1 x n) sparse
has_key D.has_key(k) -> True if D has a key k, else False
items D.items() -> list of D’s (key, value) pairs, as 2-tuples
iteritems D.iteritems() -> an iterator over the (key, value) items of D
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3.14. Sparse matrices (scipy.sparse) 371