TESTING/EIG/ssgt01.f(3) | Library Functions Manual | TESTING/EIG/ssgt01.f(3) |
NAME
TESTING/EIG/ssgt01.f
SYNOPSIS
Functions/Subroutines
subroutine ssgt01 (itype, uplo, n, m, a, lda, b, ldb, z,
ldz, d, work, result)
SSGT01
Function/Subroutine Documentation
subroutine ssgt01 (integer itype, character uplo, integer n, integer m, real, dimension( lda, * ) a, integer lda, real, dimension( ldb, * ) b, integer ldb, real, dimension( ldz, * ) z, integer ldz, real, dimension( * ) d, real, dimension( * ) work, real, dimension( * ) result)
SSGT01
Purpose:
SSGT01 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 symmetric matrix, B is symmetric positive definite, Z is orthogonal, 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 symmetric 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 symmetric 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. 0 <= M <= N.
A
A is REAL array, dimension (LDA, N) The original symmetric matrix A.
LDA
LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).
B
B is REAL array, dimension (LDB, N) The original symmetric positive definite matrix B.
LDB
LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N).
Z
Z is REAL 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 REAL array, dimension (N*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 144 of file ssgt01.f.
Author
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