Calculate Trace of a Matrix in R Programming – tr() Function

tr() function in R Language is used to calculate the trace of a matrix. Trace of a matrix is the sum of the values on the main diagonal(upper left to lower right) of the matrix.

Syntax: tr(x)

Parameters:
x: Matrix

Example 1:

# R program to calculate
# trace of a matrix

# Loading library
library(psych)

# Creating a matrix
A = matrix(
  c(6, 1, 1, 4, -2, 5, 2, 8, 7),
  nrow = 3,
  ncol = 3,
  byrow = TRUE
)

A

# Calling tr() function
cat("Trace of A:\n")
tr(A)

Output:

     [, 1] [, 2] [, 3]
[1, ]    6    1    1
[2, ]    4   -2    5
[3, ]    2    8    7
Trace of A:
[1] 11

Example 2:

# R program to calculate
# trace of a matrix

# Loading library
library(psych)

# Creating a matrix
A = matrix(c(1:9), 3, 3)

A

# Calling tr() function
cat("Trace of A:\n")
tr(A)

Output:

     [, 1] [, 2] [, 3]
[1, ]    1    4    7
[2, ]    2    5    8
[3, ]    3    6    9
Trace of A:
[1] 15