LAPACK  3.5.0
LAPACK: Linear Algebra PACKage
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ssgt01.f File Reference

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Functions/Subroutines

subroutine ssgt01 (ITYPE, UPLO, N, M, A, LDA, B, LDB, Z, LDZ, D, WORK, RESULT)
 SSGT01 More...
 

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
[in]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
[in]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
[in]N
          N is INTEGER
          The order of the matrix A.  N >= 0.
[in]M
          M is INTEGER
          The number of eigenvalues found.  0 <= M <= N.
[in]A
          A is REAL array, dimension (LDA, N)
          The original symmetric matrix A.
[in]LDA
          LDA is INTEGER
          The leading dimension of the array A.  LDA >= max(1,N).
[in]B
          B is REAL array, dimension (LDB, N)
          The original symmetric positive definite matrix B.
[in]LDB
          LDB is INTEGER
          The leading dimension of the array B.  LDB >= max(1,N).
[in]Z
          Z is REAL 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 REAL array, dimension (N*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 146 of file ssgt01.f.

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