LAPACK  3.5.0
LAPACK: Linear Algebra PACKage
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csgt01.f File Reference

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Functions/Subroutines

subroutine csgt01 (ITYPE, UPLO, N, M, A, LDA, B, LDB, Z, LDZ, D, WORK, RWORK, RESULT)
 CSGT01

Function/Subroutine Documentation

subroutine csgt01 ( integer  ITYPE,
character  UPLO,
integer  N,
integer  M,
complex, dimension( lda, * )  A,
integer  LDA,
complex, dimension( ldb, * )  B,
integer  LDB,
complex, dimension( ldz, * )  Z,
integer  LDZ,
real, dimension( * )  D,
complex, dimension( * )  WORK,
real, dimension( * )  RWORK,
real, dimension( * )  RESULT 
)

CSGT01

Purpose:
 CSGT01 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 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 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 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 REAL array, dimension (M)
          The computed eigenvalues of the generalized eigenproblem.
[out]WORK
          WORK is COMPLEX array, dimension (N*N)
[out]RWORK
          RWORK is REAL array, dimension (N)
[out]RESULT
          RESULT is REAL array, dimension (1)
          The test ratio as described above.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date
November 2011

Definition at line 152 of file csgt01.f.

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