maximise_trace: Maximise the trace of a matrix.

In Alanocallaghan/nalar: Various things I want it to do

Maximise the trace of a matrix.

Description

Maximising the trace of a matrix amounts to maximising the diagonal elements. This is useful when comparing clustering methods, or comparing clustering results with known ground truth labels.

Usage

maximise_trace(mat)

Arguments

mat	Input matrix

Value

A matrix with rows permuted such that tr(mat) is maximised.

Examples

# say we have the output of a clustering algorithm on 100 samples
a <- sample(letters[1:5], 100, replace = TRUE)
# now imagine we repeat it and get different labels for the same clusters
releveler <- setNames(letters[1:5], sample(letters[1:5]))
b <- releveler[a]
# comparing the results, it can be hard to spot which cluster is which
table(a, b)
# if we permute the rows to maximise the trace it's pretty obvious
maximise_trace(table(a, b))

Alanocallaghan/nalar documentation built on Feb. 27, 2023, 3:27 p.m.