Module imagingbook.common
Package imagingbook.common.math.eigen.eispack

Class QZHES

java.lang.Object
imagingbook.common.math.eigen.eispack.QZHES
public abstract class QZHES extends Object

  • Method Summary

    Modifier and Type
    Method
    Description
    static void
    qzhes(double[][] a, double[][] b, boolean matz, double[][] z)
    This subroutine is the first step of the qz algorithm for solving generalized matrix eigenvalue problems, SIAM J.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • qzhes

      public static void qzhes(double[][] a, double[][] b, boolean matz, double[][] z)

      This subroutine is the first step of the qz algorithm for solving generalized matrix eigenvalue problems, SIAM J. Numer. Anal. 10, 241-256 (1973) by Moler and Stewart. This description has been adapted from the original version (dated August 1983).

      This subroutine accepts a pair of real general matrices and reduces one of them to upper Hessenberg form and the other to upper triangular form using orthogonal transformations. It is usually followed by qzit, qzval and, possibly, qzvec.

      On output:

      • a has been reduced to upper hessenberg form. The elements below the first subdiagonal have been set to zero.
      • b has been reduced to upper triangular form. The elements below the main diagonal have been set to zero.
      • z contains the product of the right hand transformations if matz has been set to true. Otherwise, z is not referenced.
      Parameters:
      a - contains a real general matrix.
      b - contains a real general matrix.
      matz - should be set to true if the right hand transformations are to be accumulated for later use in computing eigenvectors, and to false otherwise.
      z - on output, contains the product of the right hand transformations if matz has been set to true. Otherwise, z is not referenced.