ssgt01.f - Man Page

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

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page ssgt01(3) is an alias of ssgt01.f(3).

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK