Create a Symmetric Matrix from a Vector

Creates a square symmetric matrix from a vector.

symMat(x, diag = TRUE, byrow = FALSE, names = FALSE)

Arguments

x: A numeric vector used to fill the upper or lower triangle of the matrix.
diag: Logical. If TRUE (the default), the diagonals of the created matrix are replaced by elements of x; otherwise, the diagonals of the created matrix are replaced by "1".
byrow: Logical. If FALSE (the default), the created matrix is filled by columns; otherwise, the matrix is filled by rows.
names: Either a logical or a character vector of names for the rows and columns of the matrix. If FALSE, no names are assigned; if TRUE, rows and columns are named X1, X2, ... .

Value

A symmetric square matrix based on column major ordering of the elements in x.

Author

Originally from metaSEM::vec2symMat, Mike W.-L. Cheung <mikewlcheung@nus.edu.sg>; modified by Michael Friendly

Examples

symMat(1:6)
#>      [,1] [,2] [,3]
#> [1,]    1    2    3
#> [2,]    2    4    5
#> [3,]    3    5    6
symMat(1:6, byrow=TRUE)
#>      [,1] [,2] [,3]
#> [1,]    1    2    4
#> [2,]    2    3    5
#> [3,]    4    5    6
symMat(5:0, diag=FALSE)
#>      [,1] [,2] [,3] [,4]
#> [1,]    1    5    4    3
#> [2,]    5    1    2    1
#> [3,]    4    2    1    0
#> [4,]    3    1    0    1