coordinates function

Get coordinates from compositions w.r.t. an specific basis

Calculate the coordinates of a composition with respect a given basis

coordinates(X, basis = "ilr", basis_return = TRUE)

coord(..., basis = "ilr")

alr_c(X)

clr_c(X)

ilr_c(X)

olr_c(X)

Arguments

• X: compositional dataset. Either a matrix, a data.frame or a vector
• basis: basis used to calculate the coordinates. basis can be either a string or a matrix. Accepted values for strings are: 'ilr' (default), 'clr', 'alr', 'pw', 'pc', 'pb' and 'cdp'. If basis is a matrix, it is expected to have log-ratio basis given in columns.
• basis_return: Should the basis be returned as attribute? (default: TRUE)
• ...: components of the compositional data

Returns

Coordinates of composition X with respect the given basis.

Details

coordinates function calculates the coordinates of a compositiona w.r.t. a given basis. basis parameter is used to set the basis, it can be either a matrix defining the log-contrasts in columns or a string defining some well-known log-contrast: 'alr' 'clr', 'ilr', 'pw', 'pc', 'pb' and 'cdp', for the additive log-ratio, centered log-ratio, isometric log-ratio, pairwise log-ratio, clr principal components, clr principal balances or default's CoDaPack balances respectively.

Examples

coordinates(c(1,2,3,4,5))
h = coordinates(c(1,2,3,4,5))
basis(h)
# basis is shown if 'coda.base.basis' option is set to TRUE
options('coda.base.basis' = TRUE)
coordinates(c(1,2,3,4,5))
# Default transformation can improve performance.
N = 100
K = 1000
X = matrix(exp(rnorm(N*K)), nrow=N, ncol=K)
system.time(coordinates(X, alr_basis(K)))
system.time(coordinates(X, 'alr'))

See Also

See functions ilr_basis, alr_basis, clr_basis, sbp_basis

to define different compositional basis. See function composition to obtain details on how to calculate a compositions from given coordinates.