LabWindows/CVI

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CxEigenVBack

Advanced Analysis Library Only

AnalysisLibErrType CxEigenVBack (void *inputEigenvectors, ssize_t numberOfEigenvectors, int side, int method, ssize_t indexLow, ssize_t indexHigh, double scale[], void *outputEigenvectors);

Purpose

Transforms the complex eigenvectors of a balanced matrix to those of the original matrix. If you want more accurate eigenvectors for an unsymmetric matrix, complete the following steps:

  1. Balance the original matrix using MatrixBalance or CxMatrixBalance.
  2. Call GenEigenValueVector or CxEigenValueVector to get the eigenvectors of the balanced matrix.
  3. Call CxEigenVBack to back-transform the eigenvectors of the balanced matrix to the eigenvectors of the original matrix.

Parameters

Input
Name Type Description
inputEigenvectors void * The eigenvectors of the balanced matrix.
numberOfEigenvectors ssize_t The order of inputEigenvectors.
side int Specifies whether inputEigenvectors contains right side eigenvectors or left side eigenvectors. side must be one of the following values:
  • RIGHT_EIGEN (0): right side eigenvectors
  • LEFT_EIGEN (1): left side eigenvectors
method int Specifies how the original matrix is balanced. method should be the same value as passed to CxMatrixBalance or MatrixBalance when the original matrix was balanced.
indexLow ssize_t The permutation information from CxMatrixBalance or MatrixBalance.
indexHigh ssize_t The permutation information from CxMatrixBalance or MatrixBalance.
scale double [] The scale information from CxMatrixBalance or MatrixBalance.
Output
Name Type Description
outputEigenvectors void * The eigenvectors of the original matrix. If outputEigenvectors = NULL or outputEigenvectors = inputEigenvectors, the back-transformed eigenvectors overwrite inputEigenvectors.

Return Value

Name Type Description
status AnalysisLibErrType A value that specifies the type of error that occurred. Refer to analysis.h for definitions of these constants.

Additional Information

Library: Advanced Analysis Library

Include file: analysis.h

LabWindows/CVI compatibility: LabWindows/CVI 8.0 and later

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