[R-sig-Geo] gdistance resistanceDistance error

[Jacob van Etten]

Dear Ignacio,

The problem may also have to do with the values in the TransitionMatrix. A reproducible example would be good to have.

Jacob

On 8/05/2012, at 18:32, "ignacio.quintero" <ignacioquinterom at gmail.com> wrote:

> Dear all,
> 
> I have came across the same error using resistanceDistance (and not
> costDistance with same data):
> 
>  "#Get matrix of resistance distances. 
>  Error in Cholesky(Lr) : CHOLMOD factorization was unsuccessful 
>  In addition: Warning message: 
>  In Cholesky(Lr) : 
>    Cholmod warning 'not positive definite' at 
>  file:../Cholesky/t_cholmod_rowfac.c, line 432"
> 
> I was using also a very large raster grid (~5000000 cells). This seems to be
> the problem (do not know if because of memory): I cropped the same big
> raster into a smaller one containing the locality points (and, of course, a
> big frame outside; however, currently, I do not know if the frame extent
> will change the results...) and it worked perfectly.
> 
> Hope this helps (although I would like to know the exact problem (memory or
> other issue) with the resistanceDistance function)
> 
> Best,
> 
> Ignacio
> 
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