JordanDecomposition
yields the Jordan decomposition of a square matrix m. The result is a list {s,j} where s is a similarity matrix and j is the Jordan canonical form of m.
Examples
open allclose allScope (10)
Basic Uses (6)
Jordan decomposition of a machine-precision matrix:
Jordan decomposition of a complex matrix:
Jordan decomposition of an exact matrix with a deficient eigenspace:
The one in the third column of indicates that the eigenspace corresponding to 48 is deficient:
The third column of is therefore a generalized eigenvector where gives rather than :
Jordan decomposition of an arbitrary-precision matrix:
Jordan decomposition of a symbolic matrix:
The Jordan decomposition of large numerical matrices is computed efficiently:
Special Matrices (4)
Jordan decomposition of sparse matrices:
Eigensystems of structured matrices:
IdentityMatrix is a Jordan canonical form:
The associated similarity matrix is a square root of the identity:
Jordan decomposition of a HilbertMatrix:
Applications (12)
Generalized Eigenvectors and Diagonalizability (4)
For the matrix , interpret the columns of the matrix of the Jordan decomposition in terms of true eigenvectors and generalized eigenvectors:
Compute the Jordan decomposition:
Columns of for which there is no above the diagonal in the corresponding of —columns 1, 3 and 4—are true eigenvectors for which :
The remaining column is a generalized eigenvector for which :
Show that the following matrix only has a single eigenvector, but it has a complete chain of generalized eigenvectors that form a basis for :
Eigensystem shows 84 is an eigenvalue of multiplicity 4 that has just one independent eigenvector:
The first column of the matrix of JordanDecomposition is the one eigenvector found:
The remaining columns are a chain for which :
Since has an empty NullSpace, its columns form a basis for :
A square matrix has a complete set of eigenvectors, and thus is diagonalizable, iff its matrix is diagonal:
Test if a particular matrix is diagonalizable:
Confirm using DiagonalizableMatrixQ:
Estimate the probability that a 4×4 matrix of ones and zeros will be diagonalizable:
An × matrix is nilpotent if for some :
Consider a non-diagonalizable matrix :
can be written as a sum of a diagonalizable matrix and a nilpotent matrix using JordanDecomposition:
Let be the matrix formed from and the diagonal part of :
Let be the matrix formed from and the superdiagonal part of :
Diagonalization (4)
For a diagonalizable matrix, the Jordan decomposition directly gives a diagonalization as . Apply this to diagonalize the matrix :
Compute the Jordan decomposition:
Let be the linear transformation whose standard matrix is given by the matrix . Find a basis for with the property that the representation of in that basis is diagonal:
Find the Jordan decomposition of :
Let consist of the eigenvectors, i.e the columns of . As converts from -coordinates to standard coordinates, its inverse converts in the reverse direction:
Thus is given by , which is diagonal:
Note that this is simply the diagonal matrix whose entries are the eigenvalues:
A real-valued symmetric matrix is orthogonally diagonalizable as , with diagonal and real valued and orthogonal. Verify that the following matrix is symmetric and then diagonalize it:
Compute the Jordan decomposition:
Let equal after normalizing its columns:
Confirm that is indeed orthogonal:
A matrix is called normal if . Normal matrices are the most general kind of matrix that can be diagonalized by a unitary transformation. All real symmetric matrices are normal because both sides of the equality are simply :
Show that the following matrix is normal, then diagonalize it:
Confirm using NormalMatrixQ:
Compute the Jordan decomposition:
Unlike a real symmetric matrix, the diagonal matrix is complex valued:
Matrix Functions and Dynamical Systems (4)
Use the Jordan decomposition to compute and for the following matrix :
Then . Since is upper triangular and nearly diagonal, the diagonal entries are raised to the power , and the entry becomes :
Confirm with direct computation by MatrixPower:
Applying the power series for the exponential, the diagonal entries obviously become , and the off-diagonal term is merely a re-indexed exponential sum. Thus, it too becomes :
Confirm using a direction computation by MatrixExp:
Confirm the formula for a Jordan matrix consisting of a single chain for the following matrix and the functions , and :
First compute the formula for :
Verify the computation using MatrixFunction:
The computation for is analogous:
MatrixFunction confirms the result:
As has a parameter, it is necessary to use D instead of Derivative and substitute in :
Again, MatrixFunction confirms the result when is entered using Function:
Solve the system of ODEs , , . First, construct the coefficient matrix for the right-hand side:
Compute the Jordan decomposition of :
Using the formula of the previous example, is given by:
The general solution is , for three arbitrary starting values:
Verify the solution using DSolveValue:
Produce the general solution of the dynamical system when is the following stochastic matrix:
Compute the Jordan decomposition of :
Since the is diagonal, consists of merely raising the diagonal entries to the power :
Properties & Relations (10)
JordanDecomposition[m] gives a matrix factorization of m as s.j.Inverse[s]:
Find the Jordan decomposition:
m is equal to s.j.Inverse[s]:
The eigenvalues of m are on the diagonal of j:
A matrix is diagonalizable iff the j matrix of its Jordan decomposition is diagonal:
If m is diagonalizable, the Jordan decomposition is effectively the same as Eigensystem:
The eigenvalues are on the diagonal of j:
The eigenvectors are the columns of s:
For a diagonalizable matrix, JordanDecomposition reduces function application to application to eigenvalues:
Compute the matrix exponential using diagonalization, exponentiating only the diagonal entries:
Compute the matrix exponential using MatrixExp:
Note that this is not simply the exponential of each entry:
For a non-diagonalizable matrix, the Jordan decomposition restricts function application to each generalized eigenvector chain:
The j matrix is not diagonal, so m is not diagonalizable:
The function application only extends above the diagonal for columns for which j had a 1 above the diagonal:
For a real symmetric numerical matrix, the matrix is orthogonal:
The matrix is diagonal and real valued:
For a real antisymmetric numerical matrix, the matrix is unitary:
The matrix is diagonal with pure imaginary diagonal entries:
For a real unitary numerical matrix, the matrix is unitary:
The diagonal entries lie on the unit circle:
For a normal numerical matrix, the matrix is unitary:
SchurDecomposition[n,RealBlockDiagonalFormFalse] for a numerical normal matrix :
Up to phase, this coincides with the Jordan decomposition:
The t and j matrices are equal:
To verify that q has eigenvectors as columns, set the first entry of each column to 1. to eliminate phase differences between q and s:
Possible Issues (2)
m is a 4×4 matrix with some entries differing by a small amount:
Find the Jordan decomposition using exact arithmetic:
This shows that m is diagonalizable:
Find the Jordan decomposition with machine‐number arithmetic:
Computation with machine-number arithmetic indicates that the matrix is not diagonalizable:
To machine precision, m is indistinguishable from a nearby non-diagonalizable matrix:
The matrix m has some machine-precision entries:
Due to numerical rounding, the deficient eigenspace at 2. is split into two separate eigenspaces:
Perform the computation using exact arithmetic to determine if the matrix is diagonalizable:
Text
Wolfram Research (1996), JordanDecomposition, Wolfram Language function, https://reference.wolfram.com/language/ref/JordanDecomposition.html (updated 2010).
CMS
Wolfram Language. 1996. "JordanDecomposition." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2010. https://reference.wolfram.com/language/ref/JordanDecomposition.html.
APA
Wolfram Language. (1996). JordanDecomposition. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/JordanDecomposition.html