gov.sandia.cognition.math.matrix.decomposition

## Interface EigenDecomposition

• All Known Implementing Classes:
AbstractEigenDecomposition, EigenDecompositionRightMTJ

```@CodeReview(reviewer="Jonathan McClain",
date="2006-05-16",
changesNeeded=false,
@PublicationReference(author="Wikipedia",
title="Eigendecomposition of a matrix",
type=WebPage,
year=2010,
url="http://en.wikipedia.org/wiki/Eigendecomposition_of_a_matrix")
public interface EigenDecomposition```
Performs a right eigendecomposition for symmetric or asymmetric matrices
Since:
1.0
Author:
Kevin R. Dixon
• ### Method Summary

All Methods
Modifier and Type Method and Description
`ComplexNumber` `getEigenValue(int index)`
Gets the complex-valued (potentially real and/or imaginary) eigenvalue specified by the index "index"
`ComplexNumber[]` `getEigenValues()`
Returns the array of complex-valued eigenvalues, the eigenvalues may be sorted in descending order of the magnitude of the eigenvalue, or they may be unsorted, depending on the specific implementation used
`Matrix` `getEigenVectorsImaginaryPart()`
Returns a matrix with the imaginary parts of the right eigenvalues of the underlying matrix
`Matrix` `getEigenVectorsRealPart()`
Returns a matrix with the real parts of the right eigenvalues of the underlying matrix
`ComplexNumber` `getLogDeterminant()`
Computes the natural logarithm determinant from the collection of eigenvalues
• ### Method Detail

• #### getEigenValue

`ComplexNumber getEigenValue(int index)`
Gets the complex-valued (potentially real and/or imaginary) eigenvalue specified by the index "index"
Parameters:
`index` - zero-based eigenvalue index to return
Returns:
ComplexNumber that specifies the eigenvalue
• #### getEigenValues

`ComplexNumber[] getEigenValues()`
Returns the array of complex-valued eigenvalues, the eigenvalues may be sorted in descending order of the magnitude of the eigenvalue, or they may be unsorted, depending on the specific implementation used
Returns:
array of complex-valued eigenvalues
• #### getEigenVectorsRealPart

`Matrix getEigenVectorsRealPart()`
Returns a matrix with the real parts of the right eigenvalues of the underlying matrix
Returns:
matrix containing the real parts of the right eivenvalues
• #### getEigenVectorsImaginaryPart

`Matrix getEigenVectorsImaginaryPart()`
Returns a matrix with the imaginary parts of the right eigenvalues of the underlying matrix
Returns:
matrix containing the imaginary parts of the right eivenvalues
• #### getLogDeterminant

`ComplexNumber getLogDeterminant()`
Computes the natural logarithm determinant from the collection of eigenvalues
Returns:
natural logarithm of the determinant