SimpleEVD
org.ejml.simple

## Class SimpleEVD<T extends SimpleMatrix>

• ```public class SimpleEVD<T extends SimpleMatrix>
extends Object```
Wrapper around EigenDecomposition for SimpleMatrix
• ### Constructor Summary

Constructors
Constructor and Description
`SimpleEVD(DenseMatrix64F mat)`
• ### Method Summary

Methods
Modifier and Type Method and Description
`Complex64F` `getEigenvalue(int index)`
Returns an eigenvalue as a complex number.
`T` `getEigenVector(int index)`
Used to retrieve real valued eigenvectors.
`EigenDecomposition` `getEVD()`
Returns the underlying decomposition that this is a wrapper around.
`int` `getIndexMax()`
Returns the index of the eigenvalue which has the largest magnitude.
`int` `getIndexMin()`
Returns the index of the eigenvalue which has the smallest magnitude.
`int` `getNumberOfEigenvalues()`
Returns the number of eigenvalues/eigenvectors.
`double` `quality()`
Computes the quality of the computed decomposition.
• ### Methods inherited from class java.lang.Object

`equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`
• ### Constructor Detail

• #### SimpleEVD

`public SimpleEVD(DenseMatrix64F mat)`
• ### Method Detail

• #### getNumberOfEigenvalues

`public int getNumberOfEigenvalues()`
Returns the number of eigenvalues/eigenvectors. This is the matrix's dimension.
Returns:
number of eigenvalues/eigenvectors.
• #### getEigenvalue

`public Complex64F getEigenvalue(int index)`

Returns an eigenvalue as a complex number. For symmetric matrices the returned eigenvalue will always be a real number, which means the imaginary component will be equal to zero.

NOTE: The order of the eigenvalues is dependent upon the decomposition algorithm used. This means that they may or may not be ordered by magnitude. For example the QR algorithm will returns results that are partially ordered by magnitude, but this behavior should not be relied upon.

Parameters:
`index` - Index of the eigenvalue eigenvector pair.
Returns:
An eigenvalue.
• #### getEigenVector

`public T getEigenVector(int index)`

Used to retrieve real valued eigenvectors. If an eigenvector is associated with a complex eigenvalue then null is returned instead.

Parameters:
`index` - Index of the eigenvalue eigenvector pair.
Returns:
If the associated eigenvalue is real then an eigenvector is returned, null otherwise.
• #### quality

`public double quality()`

Computes the quality of the computed decomposition. A value close to or less than 1e-15 is considered to be within machine precision.

This function must be called before the original matrix has been modified or else it will produce meaningless results.

Returns:
Quality of the decomposition.
• #### getEVD

`public EigenDecomposition getEVD()`
Returns the underlying decomposition that this is a wrapper around.
Returns:
EigenDecomposition
• #### getIndexMax

`public int getIndexMax()`
Returns the index of the eigenvalue which has the largest magnitude.
Returns:
index of the largest magnitude eigen value.
• #### getIndexMin

`public int getIndexMin()`
Returns the index of the eigenvalue which has the smallest magnitude.
Returns:
index of the smallest magnitude eigen value.