[R-sig-Geo] Raster package issue when using calc and clusterR

[Rafael Wüest]

Hi Malone

try the export argument of the clusterR function.

beginCluster(3)
param<- 15
f1<- function(x) tabulate(x, nbins=param)
clusterR(stk, calc, args=list(fun=f1), export = 'param')
endCluster()

Is this what you are after?

HTH, Rafael

On 12/05/2015 08:23, Brendan Malone wrote:
>
>
> Hi everyone,
>
> I have come into a bit of a problem when using the clusterR function from raster. My problem is on a much larger scale but I can recreate it more-or-less with the example below:
>
> require(raster)
> a <- raster(matrix(c(12,11,11,
>                       11,11,11,
>                       11,11,13),nrow=3))
>
> b <- raster(matrix(c(12,12,12,
>                       11,12,12,
>                       14,12,13),nrow=3))
>
> c <- raster(matrix(c(13,9,13,
>                       11,13,13,
>                       13,11,13),nrow=3))
>
> d <- raster(matrix(c(10,10,10,
>                       11,10,10,
>                       10,10,10),nrow=3))
>
> stk <- stack(a,b,c,d)
>
> #works
> calc(stk, function(x) tabulate(x, nbins=15))
>
> #works
> beginCluster(3)
> f1<- function(x) tabulate(x, nbins=15)
> clusterR(stk, calc, args=list(fun=f1))
> endCluster()
>
> #Does not work
> beginCluster(3)
> param<- 15
> f1<- function(x) tabulate(x, nbins=param)
> clusterR(stk, calc, args=list(fun=f1, param=15))
> endCluster()
>
> #Does not work
> beginCluster(3)
> param<- 15
> f1<- function(x) tabulate(x, nbins=param)
> clusterR(stk, calc, args=list(fun=f1))
> endCluster()
>
>
> I am a little mystified as to why the last two examples do not work. Ideally in this example I would like to change the number of bins on the fly, but presently I cannot and do not know why. The scale of my problem really requires me to use the clusterR function.
>   Maybe the answer is glaring me in the face. Maybe someone could share their wisdom on this perhaps.
>
> Regards,
>
> Brendan
>
>
> 	[[alternative HTML version deleted]]
>
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-- 
Rafael Wüest
rafael.wueest at gmail.com
http://www.rowueest.net