From Sparse Matrix to Listw
On Thu, 19 Aug 2010, Lata Rafael wrote:
Dear all, I have a problem converting a large binary sparse weight matrix (62025 * 62025) of class dgT to listw
You mean in package Matrix, and as described in ?"TsparseMatrix-class"?
Is there a function that creates a listw object from a sparse matrix?
From the description, you should be able to work out how to convert such
an object into a "spatial.neighbours" object (see listw2sn), then use sn2listw() to go the other way. Watch the attributes, as they need to be correct. Also note that the input object uses 0-base indices, but the sn object uses 1-base indices. Hope this helps, Roger
Thank you in advance. Best regards Rafael Lata [[alternative HTML version deleted]]
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Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e-mail: Roger.Bivand at nhh.no