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 fi
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 wrote:
>
> Hi all,I am having some difficulties in v
Ravi:
I believe you are under a misconception. The Vectorize() function
vectorizes the function call, **but it does not vectorize the computation
by moving loops down to the C level**, which is typically what is meant
when it is recommended that R users use inbuilt vectorized functions when
possib
Bert,Thanks a lot. This meets all my expectations for the moment. Thanks.Ravi
On Sunday, 11 August 2019, 00:52:02 CEST, Bert Gunter
wrote:
Cleaner, I think, is to use ?expand.grid and ?do.call, noting that any
n-column data frame is also an n-component list.
Using your example as befo
Rui,Thanks for your help in getting the result with for loops. That is useful,
but I have a complicated integral and I am interested in improving the
performance with the benefit of vectorization.
In the solution from Bert, I would like to know how I can extract the numerical
vector from the fu
Cleaner, I think, is to use ?expand.grid and ?do.call, noting that any
n-column data frame is also an n-component list.
Using your example as before:
> f2 <- function(a,b,m)integrate(function(x){exp(-a*x^3-b*x^2-m*x)},lower
=0,upper = Inf)
> fv <- Vectorize(f2,vectorize.args=c("a","b","m"),SIMPLI
Hello,
The following code might not be the best way of computing the integrals
for all combinations of the arguments but it gets the job done and I
believe it's readable code.
f2 <- function(a, b, c){
integrate(function(x) {exp(-a*x^3 - b*x^2 - c*x)},
lower = 0, upper = Inf)
}
Bert,Thanks a lot for your help. I have a few follow-up questions (shown in
the comment lines). Numerical values and error for a (i) vector and (ii) array.
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(a,b,m)integrate(function(x){exp(-a*x^
Ravi:
First of all, you're calling Vectorize incorrectly. The first argument must
be a function *name*, not a function call. Here's what you need to do (and
thanks for the reprex -- wouldn't have been able to help without it!):
f2 <- function(a,b,c)integrate(function(x){exp(-a*x^3-b*x^2-c*x)},low
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=
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