squareform: Vectorize and reshape distance or correlation matrices.
In mcfreund/mfutils: Personal miscellaneous utility functions

When x is a distance matrix or correlation matrix (symmetric with diagonal elements equal to 0 or 1, respectively), squareform() vectorizes this matrix (i.e., "unwraps" or "flattens") into a vector (i.e., vec->mat). When x is a vector (i.e., a distance matrix or correlation matrix) squareform() reshapes this vector into the correspoding square matrix (i.e., mat->vec).

1	squareform(x, lt = TRUE, corr = FALSE, nms = NULL)

`x`	square matrix or vector
`lt`	boolean, is only the lower-triangle (TRUE) or full matrix (all values) of interest? For `lt = TRUE` (default): when `x` is a vector, only the lower-triangle will be extracted, and when `x` is a vector, it will be assumed that it is a lower-triangle vector. For convenience, this can be toggled to extract/assume the full matrix (both triangles and diagonal) by setting `lt = FALSE`.
`corr`	boolean (defaults to FALSE, for distance matrices), defines the value of diagonal elements
`nms`	optional (applicable only when vec->mat), character vector that holds names of rows/cols of output matrix