[R] Array arithmetic

[Gang Chen]

Thank both of you for the suggestions!

Gang


On Mar 6, 2008, at 2:12 PM, Henrique Dallazuanna wrote:

> Hum you are rigth, I forgot of 'else'.
>
> On 06/03/2008, Benilton Carvalho <bcarvalh at jhsph.edu> wrote:
>> no, it won't.
>>
>>  you're doing the right math on the "valid" subset... but you're not
>>  returning the zeros where needed.... therefore, the whole thing will
>>  get recycled to match the dimensions.
>>
>>
>>  b
>>
>>
>>  On Mar 6, 2008, at 2:03 PM, Henrique Dallazuanna wrote:
>>
>>> I think this should work:
>>>
>>> array(A[abs(B) > 10e-5]/B[abs(B) > 10e-5], dim=c(L, M, N, P))
>>>
>>> On 06/03/2008, Gang Chen <gangchen6 at gmail.com> wrote:
>>>> I have two arrays A and B with dimensions of (L, M, N, P) and  
>>>> (L, M,
>>>> N), and I want to do
>>>>
>>>> for (i in 1:L) {
>>>> for (j in 1:M) {
>>>> for (k in 1:N) {
>>>>   if (abs(B[i, j, k]) > 10e-5)  C[i, j, k,] <- A[i, j, k,]/B[i,  
>>>> j, k]
>>>>   else C[i, j, k,] <- 0
>>>> }
>>>> }
>>>> }
>>>>
>>>> How can I get C more efficiently than looping?
>>>>
>>>> Thanks,
>>>> Gang
>>>>
>>>> ______________________________________________
>>>> R-help at r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide http://www.R-project.org/ 
>>>> posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>
>>>
>>>
>>> --
>>> Henrique Dallazuanna
>>> Curitiba-Paraná-Brasil
>>> 25° 25' 40" S 49° 16' 22" O
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide http://www.R-project.org/posting- 
>>> guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
>>
>
>
> -- 
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting- 
> guide.html
> and provide commented, minimal, self-contained, reproducible code.