[R] integrate with vector arguments

[David Winsemius]

> On Feb 27, 2015, at 4:49 AM, marKo <mtoncic at ffri.hr> wrote:
> 
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> Gee. That simple. I knew that!
> Thanks a lot.
> Essentially, I needed only the diagonal elements.
> Easily solved by:
> 
> diag(outer( X=v1,Y=v2, FUN= fV)
> 
> I am sure that there are simpler options, but that works like a charm.

If I had understood that you wanted only the values with v1 and v2 paired, then I would have suggested using apply:

> mapply(fV, v1, v2)
[1] 0.8333333 1.6666667 2.5000000 3.3333333 4.1666667

— 
David.
> 
> Thanks a lot.
> 
> Cheers,
> 
> Marko
> 
> 
> 
> On 02/27/2015 06:49 AM, David Winsemius wrote:
>> 
>>> On Feb 26, 2015, at 1:49 PM, marKo <mtoncic at ffri.hr> wrote:
>>> 
>>> v1<-c(1:5)
>>> v2<-c(1:5)
>>> 
>>> f1<-function (x) {v1*x+v2*x^2}
>>> 
>>> The problem is that integrate(f1, 0, 1) does not work.
>>> I does not, even if a pas the arguments (v1, v2)
>>> 
>>> f1<-function (x, v1, v2) {v1*x+v2*x^2}
>>> 
>>> or if i try to vectorize the function
>>> 
>>> f1<-Vectorize(function(x, v1, v2){v1*x+v2*x^2},
>>> vectorize.args=c("v1", "v2"))
>>> 
>>> integrate(f1, 0, 1) gives an error:
>> 
>> 
>>> f1<-function (X, Y) integrate( function(x) {X*x+Y*x^2}, 0, 1)$value
>>> fV<-Vectorize(f1)
>>> outer( X=v1,Y=v2, FUN= fV)
>>          [,1]     [,2] [,3]     [,4]     [,5]
>> [1,] 0.8333333 1.166667  1.5 1.833333 2.166667
>> [2,] 1.3333333 1.666667  2.0 2.333333 2.666667
>> [3,] 1.8333333 2.166667  2.5 2.833333 3.166667
>> [4,] 2.3333333 2.666667  3.0 3.333333 3.666667
>> [5,] 2.8333333 3.166667  3.5 3.833333 4.166667
>> 
>> — 
>> David Winsemius, MD
>> Alameda, CA, USA
>> 
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David Winsemius, MD
Alameda, CA, USA