loop is going to take 26 hours - needs to be quicker!
Hi if I understand correctly, you have one column you need to reformat into array. Array is basically a vector with dim attribute. Therefore if your data were properly sorted you could use just gpcc.array <- array(gpccnata2[,5], c(144,72,46)) to reformat column 5 of your data frame. But you shall be 100% sure you really want an array and not any other data form. HTH Petr
On 14 Dec 2006 at 12:56, Jenny Barnes wrote:
Date sent: Thu, 14 Dec 2006 12:56:16 +0000 (GMT) From: Jenny Barnes <jmb at mssl.ucl.ac.uk> To: r-help at stat.math.ethz.ch Subject: [R] loop is going to take 26 hours - needs to be quicker! Send reply to: Jenny Barnes <jmb at mssl.ucl.ac.uk> <mailto:r-help-request at stat.math.ethz.ch?subject=unsubscribe> <mailto:r-help-request at stat.math.ethz.ch?subject=subscribe>
Dear R-help,
I have a loop, which is set to take about 26 hours to run at the rate
it's going - this is ridiculous and I really need your help to find a
more efficient way of loading up my array gpcc.array:
#My data is stored in a table format with all the data in one long
#column running though every longitute, for every latitude, for every
#year. The original data is sotred as gpcc.data2 where dim(gpcc.data2)
#= [476928,5] where the 5th column is the data:
#make the array in the format I need [longitude,latitude,years]
gpcc.array <- array(NA, c(144,72,46))
n=0
for(k in 1:46){
for(j in 1:72){
for(i in 1:144){
n <- n+1
gpcc.array[i,j,k] <- gpcc.data2[n,5]
print(j)
}
}
}
So it runs through all the longs for every lat for every year - which
is the order the data is running down the column in gpcc.data2 so n
increses by 1 each time and each data point is pulled off....
It needs to be a lot quicker, I'd appreciate any ideas!
Many thanks for taking time to read this,
Jenny Barnes
~~~~~~~~~~~~~~~~~~
Jennifer Barnes
PhD student - long range drought prediction
Climate Extremes
Department of Space and Climate Physics
University College London
Holmbury St Mary, Dorking
Surrey
RH5 6NT
01483 204149
07916 139187
Web: http://climate.mssl.ucl.ac.uk
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Petr Pikal petr.pikal at precheza.cz