# [R] lower and upper limits in integrate as vectors

Andreas Wittmann andreas_wittmann at gmx.de
Sat Sep 20 14:50:32 CEST 2008

```dear baptiste,

thank you very much, that was excatly what i was looking for:-)

best regards

Andreas

baptiste auguie wrote:
> Hi,
>
> I think you want to Vectorize integrate(), not integrand(). Here's a
> way using mapply,
>
>> integrand <- function(z)
>> {
>> return(z * z)
>> }
>>
>> vec1<-1:3
>> vec2<-2:4
>>
>> mapply(integrate, lower=vec1, upper=vec2, MoreArgs=list(f=integrand) )
>
> baptiste
>
> On 20 Sep 2008, at 13:08, Andreas Wittmann wrote:
>
>> Dear R useRs,
>>
>> i try to integrate the following function for many values
>>
>> "integrand" <- function(z)
>> {
>> return(z * z)
>> }
>>
>> i do this with a for-loop
>>
>> for(i in 2:4)
>> {
>> z <- integrate(integrand, i-1, i)\$value
>> cat("z", z, "\n")
>> }
>>
>> to speed up the computation for many values i tried vectors
>> in integrate to do this.
>>
>> vec1<-1:3
>> vec2<-2:4
>>
>> integrate(Vectorize(integrand), vec1, vec2)\$value
>>
>> but here it seems the integration works only for the first values of
>> vec1 and vec2.
>>
>> If you have any advice how i can to this computations with vectors or
>> something like that, i would be very thankful,
>>
>> best regards
>>
>> Andreas
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> _____________________________
>
> Baptiste Auguié
>
> School of Physics
> University of Exeter