# expokit_dgpadm: EXPOKIT dgpadm matrix exponentiation on a square matrix In kexpmv: Matrix Exponential using Krylov Subspace Routines

## Description

This function exponentiates a matrix via the EXPOKIT padm function.

## Usage

 `1` ```expokit_dgpadm(mat = NULL, t = 15, transpose_needed = TRUE) ```

## Arguments

 `mat` an input square matrix. `t` time value to exponentiate by. `transpose_needed` If TRUE (default), matrix will be transposed.

## Details

From EXPOKIT:

`* Computes exp(t*H), the matrix exponential of a general matrix in `
`* full, using the irreducible rational Pade approximation to the `
`* exponential function exp(x) = r(x) = (+/-)( I + 2*(q(x)/p(x)) ), `
`* combined with scaling-and-squaring. `

This function is recommended when dealing with small dense matrices. However it can also be used for large sparse matrices when the infinity norm is approximately >100.

## Author(s)

Meabh G. McCurdy mmccurdy01@qub.ac.uk
Nicholas J. Matzke nickmatzke.ncse@gmail.com

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10``` ```# Define input matrix to be exponentiated mat=matrix(c(-0.071207, 0.065573, 0.005634, 0, -0.041206, 0.041206, 0, 0, 0), nrow=3, byrow=TRUE) # Define value of t t=15 # Exponentiate with EXPOKIT's dgpadm Pmat = expokit_dgpadm(mat=mat, t=t, transpose_needed=TRUE) print(Pmat) ```

kexpmv documentation built on May 1, 2019, 7:56 p.m.