replacing elements of distance matrix
replace dist with mahalanobis distance in the following example. a <- cbind(runif(10), sample(1:3, 10, replace=T)) a.L <- split(a,a[,2]) dist.L <- lapply(a.L, dist) Nikhil Kaza Asst. Professor, City and Regional Planning University of North Carolina nikhil.list at gmail.com
On Jul 19, 2010, at 9:24 AM, Michael Ralph M. Abrigo wrote:
Hi! I am trying to implement non-bipartite matching. I have around 500 sites which can be clustered by 10 regions. I am able to calculate pairwise Mahalanobis distances between sites (thanks to another post in the forum). However, I want to constrain my match to sites within the same region. Thus I want to replace elements of the distance matrix with a high value, say 999999, for sites not of the same region so that the pair will not be matched. In the original data file I have information on which sites belong to what region. However, when I compute for pairwise Mahalanobis distances, I only use a subset of the file, which, naturally, does not include the georeference of the sites. How should I do this? Any hint will be most appreciated. Btw, I am relatively new in using R. I may export the matrix to another program and replace the elements there, but that is a very very dirty and rough trick that I would rather not do given better options. Many thanks in advance. Cheers, Michael -- "I am most anxious for liberties for our country... but I place as a prior condition the education of the people so that our country may have an individuality of its own and make itself worthy of liberties... " Jose Rizal,1896 [[alternative HTML version deleted]]
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