Hi all,I would like to thank every one who has responded to my question. I
have received valuable help.Linus, the function that I gave here is just a toy
function. I think that is possible even to find an analytical solution. I chose
that just to include many constant parameters. I wanted to find out how I can
vectorize. I have obtained nice answers from Bert and I appreciate the help. I
knew even previously that the vectorizing primarily improves the readability of
the code. Thanks Bert for making it crystal clear that the looping is still at
the interpreted level of R.Thanks,Ravi
On Sunday, 11 August 2019, 12:24:43 CEST, Linus Chen
<linus.l.c...@gmail.com> wrote:
Dear ravi,
In your example, the function "f" is linear to a, b, and c.
Is this the general case in your task?
If it is, you can save *lots* of computation taking advantage of the linearity.
Lei
On Sat, 10 Aug 2019 at 19:20, ravi via R-help <r-help@r-project.org> wrote:
>
> Hi all,I am having some difficulties in vectorizing the integrate function.
> Let me explain with an example.
> a <- 10; b <- 3; c <- 4
> f <- function(x) {exp(-a*x^3-b*x^2-c*x)}
> integrate(f,0,Inf) # works fine
>
> My difficulties start when I want to vectorize.
>
> # attempts to vectorize fail
> a <- seq(from=0,to=1,by=0.5)
> b <- seq(from=5,to=10,by=1)
> m <- seq(from=10,to=20,by=5)
> f2 <- function(x,a,b,c) {exp(-a*x^3-b*x^2-m*x)}
> fv <-
> Vectorize(integrate(f2,0,Inf),vectorize.args=c("a","b","m"),SIMPLIFY=TRUE)
>
> I want the result as a 3-d array with dimensions of the lengths of a, b and
> c. I have tried several variants but am not having much luck. Will appreciate
> any help that I can get.
> Thanks,Ravi Sutradhara
>
>
>
>
> [[alternative HTML version deleted]]
>
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