TESTING/EIG/dsgt01.f(3)

NAME
TESTING/EIG/dsgt01.f

SYNOPSIS

  Functions/Subroutines
subroutine dsgt01 (itype, uplo, n, m, a, lda, b, ldb, z, ldz, d, work, result)
DSGT01

Function/Subroutine Documentation

  subroutine dsgt01 (integer itype, character uplo, integer n, integer m, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldb, * ) b, integer ldb, double precision, dimension( ldz, * ) z, integer ldz, double precision, dimension( * ) d, double precision, dimension( * ) work, double precision, dimension( * ) result)

DSGT01

Purpose:

     DDGT01 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 DOUBLE PRECISION 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 DOUBLE PRECISION 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 DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension (M)
              The computed eigenvalues of the generalized eigenproblem.

    WORK

              WORK is DOUBLE PRECISION array, dimension (N*N)

    RESULT

              RESULT is DOUBLE PRECISION 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 dsgt01.f.

Author

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