On Fri, Aug 26, 2011 at 12:38 PM, Mark Janikas <mjani...@esri.com> wrote:
> Charles! That looks like it could be a winner! It looks like you always > choose the last column of the U matrix and ID the columns that have the same > values? It works when I add extra columns as well! BTW, sorry for my lack > of knowledge… but what was the point of the dot multiply at the end? That > they add up to essentially zero, indicating singularity? Thanks so much! > The indicator of collinearity is the singular value in d, the corresponding column in u represent the linear combination of rows that are ~0, the corresponding row in v represents the linear combination of columns that are ~0. If you have several combinations that are ~0, of course you can add them together and get another. Basically, if you take the rows in v corresponding to small singular values, you get a basis for the for the null space of the matrix, the corresponding columns in u are a basis for the orthogonal complement of the range of the matrix. If that is getting a bit technical you can just play around with things. <snip> Chuck
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