dget54.f3

Usage

Functions/Subroutines

subroutine dget54 (n, a, lda, b, ldb, s, lds, t, ldt, u, ldu, v, ldv, work, result)
DGET54

Function/Subroutine Documentation

subroutine dget54 (integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldb, * ) b, integer ldb, double precision, dimension( lds, * ) s, integer lds, double precision, dimension( ldt, * ) t, integer ldt, double precision, dimension( ldu, * ) u, integer ldu, double precision, dimension( ldv, * ) v, integer ldv, double precision, dimension( * ) work, double precision result)

DGET54

Purpose:

!>
!> DGET54 checks a generalized decomposition of the form
!>
!>          A = U*S*V'  and B = U*T* V'
!>
!> where ' means transpose and U and V are orthogonal.
!>
!> Specifically,
!>
!>  RESULT = ||( A - U*S*V', B - U*T*V' )|| / (||( A, B )||*n*ulp )
!>

Parameters

!>          N is INTEGER
!>          The size of the matrix.  If it is zero, DGET54 does nothing.
!>          It must be at least zero.
!>

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

LDA

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

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

LDB

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

!>          S is DOUBLE PRECISION array, dimension (LDS, N)
!>          The factored matrix S.
!>

LDS

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

!>          T is DOUBLE PRECISION array, dimension (LDT, N)
!>          The factored matrix T.
!>

LDT

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

!>          U is DOUBLE PRECISION array, dimension (LDU, N)
!>          The orthogonal matrix on the left-hand side in the
!>          decomposition.
!>

LDU

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

!>          V is DOUBLE PRECISION array, dimension (LDV, N)
!>          The orthogonal matrix on the left-hand side in the
!>          decomposition.
!>

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 (3*N**2)
!>

RESULT

!>          RESULT is DOUBLE PRECISION
!>          The value RESULT, It 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 154 of file dget54.f.