deLenn wrote:

> Hi,

>

> Does scipy have an equivalent to Matlab's 'find' function, to list the

> indices of all nonzero elements in a sparse matrix?
You will want to ask scipy questions on the scipy list.

http://www.scipy.org/Mailing_Lists
There is no explicit interface on sparse matrix objects to expose the indices of

the nonzero elements. A different implementation would have to be written for

each type of sparse matrix format. However, if one can spare the memory, one can

convert to the coordinate list format and read the row and column indices from

that object.

In [1]: from scipy.sparse import lil_matrix

In [2]: A = lil_matrix((3,3))

In [3]: A[1,2] = 10

In [4]: A[2,0] = -10

In [5]: Acoo = A.tocoo()

In [6]: Acoo.row

Out[6]: array([2, 1])

In [7]: Acoo.col

Out[7]: array([0, 2])

--

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma

that is made terrible by our own mad attempt to interpret it as though it had

an underlying truth."

-- Umberto Eco