TEST_MATRIX_EXPONENTIAL
Matrix Exponential TESTS

TEST_MATRIX_EXPONENTIAL is a FORTRAN90 library which contains some simple tests for software that computes the matrix exponential function.

Formally, for a square matrix A and scalar t, the matrix exponential exp(A*t) can be defined as the sum:

exp(A*t) = sum ( 0 <= i < oo ) A^i t^i / i!

The simplest form of the matrix exponential problem asks for the value when t = 1, that is

exp(A) = sum ( 0 <= i < oo ) A^i / i!

TEST_MATRIX_EXPONENTIAL needs the C8LIB and R8LIB libraries.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

TEST_MATRIX_EXPONENTIAL is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version and a Python version.

Related Data and Programs:

EXPOKIT, a FORTRAN77 library which solves various forms of the matrix exponential problem, by Roger Sidje.

MATRIX_EXPONENTIAL, a FORTRAN90 library which demonstrates some simple approaches to the problem of computing the exponential of a matrix.

R8LIB, a FORTRAN90 library which contains many utility routines using double precision real (R8) arithmetic.

TEST_MAT, a FORTRAN90 library which defines test matrices.

Reference:

1. Alan Laub,
   Review of "Linear System Theory" by Joao Hespanha,
   SIAM Review,
   Volume 52, Number 4, December 2010, page 779-781.
2. Cleve Moler, Charles VanLoan,
   Nineteen Dubious Ways to Compute the Exponential of a Matrix, SIAM Review,
   Volume 20, Number 4, October 1978, pages 801-836.
3. Cleve Moler, Charles VanLoan,
   Nineteen Dubious Ways to Compute the Exponential of a Matrix, Twenty-Five Years Later,
   SIAM Review,
   Volume 45, Number 1, March 2003, pages 3-49.
4. Cleve Moler,
   Cleve's Corner: A Balancing Act for the Matrix Exponential,
   July 23rd, 2012.
5. Roger Sidje,
   EXPOKIT: Software Package for Computing Matrix Exponentials,
   ACM Transactions on Mathematical Software,
   Volume 24, Number 1, 1998, pages 130-156.
6. Robert Ward,
   Numerical computation of the matrix exponential with accuracy estimate,
   SIAM Journal on Numerical Analysis,
   Volume 14, Number 4, September 1977, pages 600-610.

Source Code:

• test_matrix_exponential.f90, the source code.

Examples and Tests:

• test_matrix_exponential_test.f90, a sample calling program.
• test_matrix_exponential_test.txt, the output file.

List of Routines:

• C8MAT_EXP_A returns the matrix for a given test.
• C8MAT_EXP_EXPA returns the "exact" exponential matrix for a given test.
• C8MAT_EXP_N returns the matrix order for a given test.
• C8MAT_EXP_STORY prints explanatory text for each problem.
• C8MAT_EXP_TEST_NUM returns the number of matrix exponential tests.
• R8MAT_EXP_A returns the matrix for a given test.
• R8MAT_EXP_EXPA returns the "exact" exponential matrix for a given test.
• R8MAT_EXP_N returns the matrix order for a given test.
• R8MAT_EXP_STORY prints explanatory text for each problem.
• R8MAT_EXP_TEST_NUM returns the number of matrix exponential tests.

You can go up one level to the FORTRAN90 source codes.