# pysal.lib.weights.lat2SW¶

pysal.lib.weights.lat2SW(nrows=3, ncols=5, criterion='rook', row_st=False)[source]

Create a sparse W matrix for a regular lattice.

Parameters: nrows : int number of rows ncols : int number of columns rook : {“rook”, “queen”, “bishop”} type of contiguity. Default is rook. row_st : boolean If True, the created sparse W object is row-standardized so every row sums up to one. Defaults to False. w : scipy.sparse.dia_matrix instance of a scipy sparse matrix

Notes

Observations are row ordered: first k observations are in row 0, next k in row 1, and so on. This method directly creates the W matrix using the strucuture of the contiguity type.

Examples

>>> from pysal.lib.weights import lat2W
>>> w9 = lat2SW(3,3)
>>> w9[0,1]
1
>>> w9[3,6]
1
>>> w9r = lat2SW(3,3, row_st=True)
>>> w9r[3,6] == 1./3
True