|
|||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Object org.opensourcephysics.numerics.EigenvalueDecomposition
public class EigenvalueDecomposition
Eigenvalues and eigenvectors of a real matrix.
If A is symmetric, then A = V*D*V' where the eigenvalue matrix D is diagonal and the eigenvector matrix V is orthogonal. I.e. A = V.times(D.times(V.transpose())) and V.times(V.transpose()) equals the identity matrix.
If A is not symmetric, then the eigenvalue matrix D is block diagonal with the real eigenvalues in 1-by-1 blocks and any complex eigenvalues, lambda + i*mu, in 2-by-2 blocks, [lambda, mu; -mu, lambda]. The columns of V represent the eigenvectors in the sense that A*V = V*D, i.e. A.times(V) equals V.times(D). The matrix V may be badly conditioned, or even singular, so the validity of the equation A = V*D*inverse(V) depends upon V.cond().
Constructor Summary | |
---|---|
EigenvalueDecomposition(double[][] A)
Constructs the EigenvalueDecomposition. |
Method Summary | |
---|---|
double[][] |
getEigenvalueMatrix()
Return the block diagonal eigenvalue matrix |
double[][] |
getEigenvectors()
Return the eigenvector matrix |
double[] |
getImagEigenvalues()
Return the imaginary parts of the eigenvalues |
double[] |
getRealEigenvalues()
Return the real parts of the eigenvalues |
static double |
hypot(double a,
double b)
sqrt(a^2 + b^2) without under/overflow. |
void |
recompute(double[][] A)
Check for symmetry, then recompute the eigenvalue decomposition |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
---|
public EigenvalueDecomposition(double[][] A)
A
- square matrixMethod Detail |
---|
public void recompute(double[][] A)
A
- square matrixpublic double[][] getEigenvectors()
public double[] getRealEigenvalues()
public double[] getImagEigenvalues()
public double[][] getEigenvalueMatrix()
public static double hypot(double a, double b)
|
|||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |