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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