LAPACK  3.9.0
LAPACK: Linear Algebra PACKage

◆ zsgt01()

subroutine zsgt01 ( integer  ITYPE,
character  UPLO,
integer  N,
integer  M,
complex*16, dimension( lda, * )  A,
integer  LDA,
complex*16, dimension( ldb, * )  B,
integer  LDB,
complex*16, dimension( ldz, * )  Z,
integer  LDZ,
double precision, dimension( * )  D,
complex*16, dimension( * )  WORK,
double precision, dimension( * )  RWORK,
double precision, dimension( * )  RESULT 
)

ZSGT01

Purpose:
 CDGT01 checks a decomposition of the form

    A Z   =  B Z D or
    A B Z =  Z D or
    B A Z =  Z D

 where A is a Hermitian matrix, B is Hermitian positive definite,
 Z is unitary, and D is diagonal.

 One of the following test ratios is computed:

 ITYPE = 1:  RESULT(1) = | A Z - B Z D | / ( |A| |Z| n ulp )

 ITYPE = 2:  RESULT(1) = | A B Z - Z D | / ( |A| |Z| n ulp )

 ITYPE = 3:  RESULT(1) = | B A Z - Z D | / ( |A| |Z| n ulp )
Parameters
[in]ITYPE
          ITYPE is INTEGER
          The form of the Hermitian generalized eigenproblem.
          = 1:  A*z = (lambda)*B*z
          = 2:  A*B*z = (lambda)*z
          = 3:  B*A*z = (lambda)*z
[in]UPLO
          UPLO is CHARACTER*1
          Specifies whether the upper or lower triangular part of the
          Hermitian matrices A and B is stored.
          = 'U':  Upper triangular
          = 'L':  Lower triangular
[in]N
          N is INTEGER
          The order of the matrix A.  N >= 0.
[in]M
          M is INTEGER
          The number of eigenvalues found.  M >= 0.
[in]A
          A is COMPLEX*16 array, dimension (LDA, N)
          The original Hermitian matrix A.
[in]LDA
          LDA is INTEGER
          The leading dimension of the array A.  LDA >= max(1,N).
[in]B
          B is COMPLEX*16 array, dimension (LDB, N)
          The original Hermitian positive definite matrix B.
[in]LDB
          LDB is INTEGER
          The leading dimension of the array B.  LDB >= max(1,N).
[in]Z
          Z is COMPLEX*16 array, dimension (LDZ, M)
          The computed eigenvectors of the generalized eigenproblem.
[in]LDZ
          LDZ is INTEGER
          The leading dimension of the array Z.  LDZ >= max(1,N).
[in]D
          D is DOUBLE PRECISION array, dimension (M)
          The computed eigenvalues of the generalized eigenproblem.
[out]WORK
          WORK is COMPLEX*16 array, dimension (N*N)
[out]RWORK
          RWORK is DOUBLE PRECISION array, dimension (N)
[out]RESULT
          RESULT is DOUBLE PRECISION array, dimension (1)
          The test ratio as described above.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date
December 2016