SRC/claqz3.f(3) Library Functions Manual SRC/claqz3.f(3)

SRC/claqz3.f


subroutine claqz3 (ilschur, ilq, ilz, n, ilo, ihi, nshifts, nblock_desired, alpha, beta, a, lda, b, ldb, q, ldq, z, ldz, qc, ldqc, zc, ldzc, work, lwork, info)
CLAQZ3

CLAQZ3

Purpose:

 CLAQZ3 Executes a single multishift QZ sweep

Parameters

ILSCHUR
          ILSCHUR is LOGICAL
              Determines whether or not to update the full Schur form

ILQ

          ILQ is LOGICAL
              Determines whether or not to update the matrix Q

ILZ

          ILZ is LOGICAL
              Determines whether or not to update the matrix Z

N

          N is INTEGER
          The order of the matrices A, B, Q, and Z.  N >= 0.

ILO

          ILO is INTEGER

IHI

          IHI is INTEGER

NSHIFTS

          NSHIFTS is INTEGER
          The desired number of shifts to use

NBLOCK_DESIRED

          NBLOCK_DESIRED is INTEGER
          The desired size of the computational windows

ALPHA

          ALPHA is COMPLEX array. SR contains
          the alpha parts of the shifts to use.

BETA

          BETA is COMPLEX array. SS contains
          the scale of the shifts to use.

A

          A is COMPLEX array, dimension (LDA, N)

LDA

          LDA is INTEGER
          The leading dimension of the array A.  LDA >= max( 1, N ).

B

          B is COMPLEX array, dimension (LDB, N)

LDB

          LDB is INTEGER
          The leading dimension of the array B.  LDB >= max( 1, N ).

Q

          Q is COMPLEX array, dimension (LDQ, N)

LDQ

          LDQ is INTEGER

Z

          Z is COMPLEX array, dimension (LDZ, N)

LDZ

          LDZ is INTEGER

QC

          QC is COMPLEX array, dimension (LDQC, NBLOCK_DESIRED)

LDQC

          LDQC is INTEGER

ZC

          ZC is COMPLEX array, dimension (LDZC, NBLOCK_DESIRED)

LDZC

          LDZ is INTEGER

WORK

          WORK is COMPLEX array, dimension (MAX(1,LWORK))
          On exit, if INFO >= 0, WORK(1) returns the optimal LWORK.

LWORK

          LWORK is INTEGER
          The dimension of the array WORK.  LWORK >= max(1,N).
          If LWORK = -1, then a workspace query is assumed; the routine
          only calculates the optimal size of the WORK array, returns
          this value as the first entry of the WORK array, and no error
          message related to LWORK is issued by XERBLA.

INFO

          INFO is INTEGER
          = 0: successful exit
          < 0: if INFO = -i, the i-th argument had an illegal value

Author

Thijs Steel, KU Leuven

Date

May 2020

Definition at line 203 of file claqz3.f.

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