On Wed, 2009-07-22 at 14:07 -0700, megh wrote:
> Thanks for your suggestions. I need one more thing :
>
> x = y = vector("list")
> for (i in 1:5) x[[i]] = rnorm(2); y[[i]] = rnorm(2)
>
> Here I want to get t(x[[i]]) %*% y[[i]] for each i. Can anyone please help
> me?
Two ways:
set.seed(123)
x
On Jul 22, 2009, at 5:07 PM, megh wrote:
Thanks for your suggestions. I need one more thing :
x = y = vector("list")
for (i in 1:5) x[[i]] = rnorm(2); y[[i]] = rnorm(2)
Here I want to get t(x[[i]]) %*% y[[i]] for each i. Can anyone
please help
me?
?lapply
Regards,
Jorge Ivan Vel
Thanks for your suggestions. I need one more thing :
x = y = vector("list")
for (i in 1:5) x[[i]] = rnorm(2); y[[i]] = rnorm(2)
Here I want to get t(x[[i]]) %*% y[[i]] for each i. Can anyone please help
me?
Regards,
Jorge Ivan Velez wrote:
>
> Hi megh,
> Perhaps?
>
> # Data
> x = vector("
On Jul 22, 2009, at 3:18 PM, megh wrote:
Hi,
I have created a list object like that :
x = vector("list")
for (i in 1:5) x[[i]] = rnorm(2)
x
So now you have a list with 5 elements
Now I want to do two things :
1. for each i, I want to do following matrix calculation : t(x[[i]])
%*%
Here's one way:
set.seed(1)
x1 <- lapply(1:5, function(i) rnorm(2))
x2 <- lapply(x1, function(x) outer(x, x))
Reduce("+", x2, 0)
[,1] [,2]
[1,] 1.768406 -1.534413
[2,] -1.534413 3.890200
and another way using the abind package:
library(abind)
dim(abind(along=0, x2))
[1] 5
Hi megh,
Perhaps?
# Data
x = vector("list")
for (i in 1:5) x[[i]] = rnorm(2)
# 2x2 matrices
res <- lapply(x, function(a) a %*% t(a) )
res
# Funcion from ?Reduce
add <- function(x) Reduce("+", x)
# Summing up!
add(res)
See ?lapply and ?Reduce for more information.
HTH,
Jorge
On Wed, Jul 22,
Hi,
I have created a list object like that :
x = vector("list")
for (i in 1:5) x[[i]] = rnorm(2)
x
Now I want to do two things :
1. for each i, I want to do following matrix calculation : t(x[[i]]) %*%
x[[i]] i.e. for each i, I want to get a 2x2 matrix
2. Next I want to get x[[1]] + x[[2]] +...
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