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propr (version 3.1.8)

aldex2propr: Import ALDEx2 Object

Description

This method constructs a propr object from an aldex.clr object. See Details.

Usage

aldex2propr(aldex.clr, how = "perb", select)

Arguments

aldex.clr

An aldex.clr object.

how

A character string. The proportionality method used to build the propr object. For example, "perb" returns an estimation of rho while "phit" returns an estimation of phi.

select

Value

Returns a propr object.

Details

The ALDEx2 package has two exceptional features useful in proportionality analysis too. First, ALDEx2 offers a number of extra log-ratio transformations, toggled by the denom argument in aldex.clr. Second, ALDEx2 estimates per-feature technical variation within each sample using Monte-Carlo instances drawn from the Dirichlet distribution.

The aldex2propr function takes advantage of both of these features by constructing a propr object directly from an aldex.clr object. When interpreting the resultant propr object, keep in mind that ALDEx2 adds 0.5 to all @counts regardless of whether the counts contain any zeros. Otherwise, the @logratio slot contains the log-ratio transformed counts as averaged across all Monte Carlo instances. Likewise, the @matrix slot gets filled with the proportionality matrix as averaged across all Monte Carlo instances.

The select argument subsets the feature matrix after log-ratio transformation but before calculating proportionality. This reduces the run-time and RAM overhead without impacting the final result. Removing lowly abundant features prior to log-ratio transformation could otherwise change the proportionality measure.