csgt013
Part of csgt01.f(3).
Usage
Functions/Subroutines
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
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 !>
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 !>
N
!> N is INTEGER !> The order of the matrix A. N >= 0. !>
M
!> M is INTEGER !> The number of eigenvalues found. M >= 0. !>
A
!> A is COMPLEX array, dimension (LDA, N) !> The original Hermitian matrix A. !>
LDA
!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
B
!> B is COMPLEX array, dimension (LDB, N) !> The original Hermitian positive definite matrix B. !>
LDB
!> LDB is INTEGER !> The leading dimension of the array B. LDB >= max(1,N). !>
Z
!> Z is COMPLEX array, dimension (LDZ, M) !> The computed eigenvectors of the generalized eigenproblem. !>
LDZ
!> LDZ is INTEGER !> The leading dimension of the array Z. LDZ >= max(1,N). !>
D
!> D is REAL array, dimension (M) !> The computed eigenvalues of the generalized eigenproblem. !>
WORK
!> WORK is COMPLEX array, dimension (N*N) !>
RWORK
!> RWORK is REAL array, dimension (N) !>
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.
Definition at line 150 of file csgt01.f.