Incidence matrix in the specified sparse format, with pore IDs indicating the non-zero values.


fmt (str, default is 'coo') –

The sparse storage format to return. Options are:

’coo’ : This is the native format of OpenPNM’s data ‘lil’ : Enables row-wise slice of the matrix ‘csr’ : Favored by most linear algebra routines ‘dok’ : Enables subscript access of locations


This method will only create the requested matrix in the specified format if one is not already saved on the object. If not present, this method will create and return the matrix, as well as store it for future use.

To obtain a matrix with weights other than pore IDs at each non-zero location use create_incidence_matrix.