metaSEM (version 1.5.0)

list2matrix: Convert a List of Symmetric Matrices into a Stacked Matrix

Description

It converts a list of symmetric matrices into a stacked matrix. Dimensions of the symmetric matrices have to be the same. It tries to preserve the dimension names if possible. Dimension names will be created if there are no dimension names in the first symmetric matrix.

Usage

list2matrix(x, diag = FALSE)

Value

A \(k\) x \(p*\) stacked matrix where \(p* = p(p-1)/2 \) for diag=FALSE or \(p* = p(p+1)/2 \) for diag=TRUE.

Arguments

x

A list of \(k\) \(p\) x \(p\) symmetric matrices.

diag

Logical. If it is TRUE, vech is used to vectorize the (covariance) matrices. If it is FALSE, vechs is used to vectorize the (correlation) matrices.

Author

Mike W.-L. Cheung <[e-mail]>

Examples

C1 <- matrix(c(1,0.5,0.4,0.5,1,0.2,0.4,0.2,1), ncol=3)  
C2 <- matrix(c(1,0.4,NA,0.4,1,NA,NA,NA,NA), ncol=3)  

## A list without dimension names 
list2matrix(list(C1, C2))
#      x2_x1 x3_x1 x3_x2
# [1,]   0.5   0.4   0.2
# [2,]   0.4    NA    NA

dimnames(C1) <- list( c("x","y","z"), c("x","y","z") )
dimnames(C2) <- list( c("x","y","z"), c("x","y","z") )

## A list with dimension names
list2matrix(list(C1, C2))
#      y_x z_x z_y
# [1,] 0.5 0.4 0.2
# [2,] 0.4  NA  NA