TESTING/EIG/dget51.f(3)

NAME
TESTING/EIG/dget51.f

SYNOPSIS

  Functions/Subroutines
subroutine dget51 (itype, n, a, lda, b, ldb, u, ldu, v, ldv, work, result)
DGET51

Function/Subroutine Documentation

  subroutine dget51 (integer itype, integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldb, * ) b, integer ldb, double precision, dimension( ldu, * ) u, integer ldu, double precision, dimension( ldv, * ) v, integer ldv, double precision, dimension( * ) work, double precision result)

DGET51

Purpose:

    !>
    !>      DGET51  generally checks a decomposition of the form
    !>
    !>              A = U B V'
    !>
    !>      where ' means transpose and U and V are orthogonal.
    !>
    !>      Specifically, if ITYPE=1
    !>
    !>              RESULT = | A - U B V' | / ( |A| n ulp )
    !>
    !>      If ITYPE=2, then:
    !>
    !>              RESULT = | A - B | / ( |A| n ulp )
    !>
    !>      If ITYPE=3, then:
    !>
    !>              RESULT = | I - UU' | / ( n ulp )
    !>

Parameters
    ITYPE

    !>          ITYPE is INTEGER
    !>          Specifies the type of tests to be performed.
    !>          =1: RESULT = | A - U B V' | / ( |A| n ulp )
    !>          =2: RESULT = | A - B | / ( |A| n ulp )
    !>          =3: RESULT = | I - UU' | / ( n ulp )
    !>

    N

    !>          N is INTEGER
    !>          The size of the matrix.  If it is zero, DGET51 does nothing.
    !>          It must be at least zero.
    !>

    A

    !>          A is DOUBLE PRECISION array, dimension (LDA, N)
    !>          The original (unfactored) matrix.
    !>

    LDA

    !>          LDA is INTEGER
    !>          The leading dimension of A.  It must be at least 1
    !>          and at least N.
    !>

    B

    !>          B is DOUBLE PRECISION array, dimension (LDB, N)
    !>          The factored matrix.
    !>

    LDB

    !>          LDB is INTEGER
    !>          The leading dimension of B.  It must be at least 1
    !>          and at least N.
    !>

    U

    !>          U is DOUBLE PRECISION array, dimension (LDU, N)
    !>          The orthogonal matrix on the left-hand side in the
    !>          decomposition.
    !>          Not referenced if ITYPE=2
    !>

    LDU

    !>          LDU is INTEGER
    !>          The leading dimension of U.  LDU must be at least N and
    !>          at least 1.
    !>

    V

    !>          V is DOUBLE PRECISION array, dimension (LDV, N)
    !>          The orthogonal matrix on the left-hand side in the
    !>          decomposition.
    !>          Not referenced if ITYPE=2
    !>

    LDV

    !>          LDV is INTEGER
    !>          The leading dimension of V.  LDV must be at least N and
    !>          at least 1.
    !>

    WORK

    !>          WORK is DOUBLE PRECISION array, dimension (2*N**2)
    !>

    RESULT

    !>          RESULT is DOUBLE PRECISION
    !>          The values computed by the test specified by ITYPE.  The
    !>          value is currently limited to 1/ulp, to avoid overflow.
    !>          Errors are flagged by RESULT=10/ulp.
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 147 of file dget51.f.

Author

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