# [R] Constructing a symmetric matrix using library(corpcor)

Steven Yen syen04 at gmail.com
Wed Feb 17 06:07:55 CET 2016

```Hello

I am constructing a symmetric matrix with library "corpcor". In the
codes below, I am able to construct a symmetric matrix of order 3 and
4. However, the 5 x 5 matrix does not seem right? Help?

Thanks.

> library(corpcor)> r  <- 1:3> rr <- vec2sm(r, diag = F)> rr <- rr[upper.tri(rr)]> r  <- vec2sm(rr, diag = F); diag(r) <- 1> r     [,1] [,2] [,3]
[1,]    1    1    2
[2,]    1    1    3
[3,]    2    3    1> > r  <- 1:6> rr <- vec2sm(r, diag = F)> rr <-
rr[upper.tri(rr)]> r  <- vec2sm(rr, diag = F); diag(r) <- 1> r
[,1] [,2] [,3] [,4]
[1,]    1    1    2    4
[2,]    1    1    3    5
[3,]    2    3    1    6
[4,]    4    5    6    1> > r  <- 1:10> rr <- vec2sm(r, diag = F)> rr
<- rr[upper.tri(rr)]> r  <- vec2sm(rr, diag = F); diag(r) <- 1> r
[,1] [,2] [,3] [,4] [,5]
[1,]    1    1    2    5    3
[2,]    1    1    6    8    4
[3,]    2    6    1    7    9
[4,]    5    8    7    1   10
[5,]    3    4    9   10    1

>

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```