Standardize a site-by-species matrix by site (row-wise z) with optional robust SD

For each site (row), subtract the row-mean and divide by a row-scale. The scale can be classical SD or a robust max(MAD, SD) with a small floor.

Usage

standardise_by_site(X, robust = FALSE)

Arguments

X

Numeric matrix (sites × species).

robust

Logical. If TRUE, uses max(MAD, SD, 1e-8) per row; else classical SD with a safe 1 fallback.

Value

List with z (z-scored matrix), mu (row means), sd (row scales).

Examples

if (FALSE) { # \dontrun{
std = standardise_by_site(C_js, robust = TRUE)
C_js_z = std$z
} # }