# [R] How to calculate correlation of a vector in R?

C W tmrsg11 at gmail.com
Mon Nov 3 01:19:56 CET 2014

```Thanks, Jeff.  I had some misunderstanding.

So, I want to calculate the squared exponential of vector v

v = c(700, 800, 1029)

formula is:
k(x_i, x_j)=sigma^2 * exp(-1/(2*l^2) * (x_i - x_j) ^2)

where,
sigma=7, l=100

I used,
> v <- c(700, 800, 1029)
> corr.matrix(cbind(v),scales=0.5)
[,1] [,2] [,3]
[1,]    1    0    0
[2,]    0    1    0
[3,]    0    0    1

the output should be covariance matrix = [49, 29.7, 0.02; 29.7, 49, 3.6;
0.2,  3.6, 49]

On Sun, Nov 2, 2014 at 7:04 PM, Jeff Newmiller <jdnewmil at dcn.davis.ca.us>
wrote:

> What is your question? The matrix form is probably what you are looking
> for, but you put the same vector in three times so if course it is all
> ones. I don't know what you expected to happen when you entered cor(v)
> since there is nothing to correlate if you only have one vector.
>
> Please post in plain text as the footer and Posting Guide request.
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>
> On November 2, 2014 3:30:14 PM PST, C W <tmrsg11 at gmail.com> wrote:
> >Hi list,
> >I have trying to calculate the covariance/correlation of three
> >elements.  I
> >have vector say,
> >
> >v <- c(700, 800, 1000)
> >
> >I want to have a 3 by 3 correlation matrix, meaning cor(v1, c2),
> >cor(v1,
> >c3), cor(v2, v3), etc...
> >
> >So far I get,
> >> cor(v)
> >Error in cor(v) : supply both 'x' and 'y' or a matrix-like 'x'
> >
> >> vvv <- cbind(v, v, v)
> >> cor(vvv)
> >  v v v
> >v 1 1 1
> >v 1 1 1
> >v 1 1 1
> >
> >
> >I am calculating squared exponential kernel as seen here.
> >http://mlg.eng.cam.ac.uk/duvenaud/cookbook/index.html
> >
> >Thanks a bunch,
> >
> >Mike
> >
> >       [[alternative HTML version deleted]]
> >
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