MatrixExp
MatrixExp[m]
gives the matrix exponential of m.
MatrixExp[m,v]
gives the matrix exponential of m applied to the vector v.
Examples
open allclose allBasic Examples (3)
Scope (12)
Basic Uses (7)
Exponentiate a machine-precision matrix:
Exponentiate a complex matrix:
Compute the exponential of an exact matrix:
The exponential of an arbitrary-precision matrix:
Exponential of a symbolic matrix:
Computing the exponential of large machine-precision matrices is efficient:
Directly applying the exponential to a single vector is even more efficient:
The exponential of a CenteredInterval matrix:
Special Matrices (5)
The exponential of a sparse matrix is returned as a normal matrix:
Directly apply the matrix exponential of a sparse matrix to a sparse vector:
Compute the exponential of a structured array:
Exponentiate IdentityMatrix:
More generally, the exponential of any diagonal matrix is the exponential of its diagonal elements:
Exponentiate HilbertMatrix:
Applications (5)
Suppose a particle is moving in a planar force field and its position vector satisfies and , where and are as follows. Solve this initial problem for :
The solution to this differential equation is :
Verify the solution using DSolveValue:
A system of first-order linear differential equations:
Write the system in the form with :
The matrix exponential gives the basis for the general solution:
The matrix exponential applied to a vector gives a particular solution:
In quantum mechanics, the energy operator is called the Hamiltonian . Given the Hamiltonian for a spin-1 particle in constant magnetic field in the direction, find the state at time of a particle that is initially in the state representing :
The system evolves according to the Schrödinger equation :
Cross products with respect to fixed three-dimensional vectors can be represented by matrix multiplication, which is useful in studying rotational motion. Construct the antisymmetric matrix representing the linear operator , where is an angular velocity about the axis:
Verify that the action of is the same as doing a cross product with :
The rotation matrix at time is the matrix exponential of times the previous matrix:
Verify using RotationMatrix:
The point at time zero will be at time :
The velocity of will be given by :
And the vector from the axis of rotation to is :
Visualize this motion and the associated vectors:
The matrix s approximates the second derivative periodic on on the grid x:
A vector representing a soliton on the grid x:
Propagate the solution of using a splitting :
Plot the solution and 10 times the error from the solution of the cubic Schrödinger equation:
Properties & Relations (10)
MatrixExp effectively uses the power series for Exp, with Power replaced by MatrixPower:
Equivalently, MatrixExp is MatrixFunction applied to Exp:
The matrix exponential of a diagonal matrix is a diagonal matrix with the diagonal entries exponentiated:
If m is diagonalizable with , then :
MatrixExp[m] is always invertible, and the inverse is given by MatrixExp[-m]:
MatrixExp of a real, antisymmetric matrix is orthogonal:
MatrixExp of an antihermitian matrix is unitary:
MatrixExp of a Hermitian matrix is positive-definite:
MatrixExp satisfies :
The matrix exponential of a nilpotent matrix is a polynomial in the exponentiation parameter:
Confirm that is nilpotent ( for some ):
can be computed from the JordanDecomposition as
Moreover, is zero except in upper triangular blocks delineated by s in the superdiagonal:
Possible Issues (1)
Neat Examples (1)
Text
Wolfram Research (1991), MatrixExp, Wolfram Language function, https://reference.wolfram.com/language/ref/MatrixExp.html (updated 2024).
CMS
Wolfram Language. 1991. "MatrixExp." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2024. https://reference.wolfram.com/language/ref/MatrixExp.html.
APA
Wolfram Language. (1991). MatrixExp. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/MatrixExp.html