[R] Yearly aggregates and matrices
Gabor Grothendieck
ggrothendieck at gmail.com
Fri Apr 29 04:16:52 CEST 2011
On Thu, Apr 28, 2011 at 10:13 PM, Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
> On Thu, Apr 28, 2011 at 4:49 PM, mathijsdevaan <mathijsdevaan at gmail.com> wrote:
>> Thanks, but it did not really improve the speed. Why is it that when I change
>> the layout of the matrix (which does not give the required results), the
>> speed increases tremendously? So:
>>
>> library(reshape2)
>> library(zoo)
>> z <- read.zoo(DF, split = 3, index = 2, FUN = identity) # Split on 3 and
>> index on 2 instead of vice versa
>> sum.na <- function(x) if (any(!is.na(x))) sum(x, na.rm = TRUE) else NA
>> r <- rollapply(z, 3, sum.na, align = "right", partial = TRUE)
>>
>> or
>>
>> mm <- melt(DF, id = c("B", "C"))
>> aa <- acast(mm, B ~ C + variable, FUN = sum) # B ~ C instead of C ~ B
>> sum.na <- function(x) if (any(!is.na(x))) sum(x, na.rm = TRUE) else NA
>> r <- rollapply(aa, 3, sum.na, align = "right", partial = TRUE)
>>
>
>
> For me it makes little difference:
>
>> system.time(for(i in 1:100) read.zoo(DF, split = 3, index = 2, FUN = identity))
> user system elapsed
> 1.72 0.00 1.71
>> system.time(for(i in 1:100) read.zoo(DF, split = 2, index = 3, FUN = identity))
> user system elapsed
> 1.75 0.00 1.74
and here it is with rollapply included:
> system.time(for(i in 1:100) { read.zoo(DF, split = 3, index = 2, FUN = identity)
+ r <- rollapply(z, 3, sum.na, align = "right", partial = TRUE)})
user system elapsed
14.74 0.00 14.76
.
> system.time(for(i in 1:100) {read.zoo(DF, split = 2, index = 3, FUN = identity)
+ r <- rollapply(z, 3, sum.na, align = "right", partial = TRUE)})
user system elapsed
14.72 0.00 14.74
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