TESTING/EIG/dgqrts.f(3)

NAME
TESTING/EIG/dgqrts.f

SYNOPSIS

  Functions/Subroutines
subroutine dgqrts (n, m, p, a, af, q, r, lda, taua, b, bf, z, t, bwk, ldb, taub, work, lwork, rwork, result)
DGQRTS

Function/Subroutine Documentation

  subroutine dgqrts (integer n, integer m, integer p, double precision, dimension( lda, * ) a, double precision, dimension( lda, * ) af, double precision, dimension( lda, * ) q, double precision, dimension( lda, * ) r, integer lda, double precision, dimension( * ) taua, double precision, dimension( ldb, * ) b, double precision, dimension( ldb, * ) bf, double precision, dimension( ldb, * ) z, double precision, dimension( ldb, * ) t, double precision, dimension( ldb, * ) bwk, integer ldb, double precision, dimension( * ) taub, double precision, dimension( lwork ) work, integer lwork, double precision, dimension( * ) rwork, double precision, dimension( 4 ) result)

DGQRTS

Purpose:

    !>
    !> DGQRTS tests DGGQRF, which computes the GQR factorization of an
    !> N-by-M matrix A and a N-by-P matrix B: A = Q*R and B = Q*T*Z.
    !>

Parameters
    N

    !>          N is INTEGER
    !>          The number of rows of the matrices A and B.  N >= 0.
    !>

    M

    !>          M is INTEGER
    !>          The number of columns of the matrix A.  M >= 0.
    !>

    P

    !>          P is INTEGER
    !>          The number of columns of the matrix B.  P >= 0.
    !>

    A

    !>          A is DOUBLE PRECISION array, dimension (LDA,M)
    !>          The N-by-M matrix A.
    !>

    AF

    !>          AF is DOUBLE PRECISION array, dimension (LDA,N)
    !>          Details of the GQR factorization of A and B, as returned
    !>          by DGGQRF, see SGGQRF for further details.
    !>

    Q

    !>          Q is DOUBLE PRECISION array, dimension (LDA,N)
    !>          The M-by-M orthogonal matrix Q.
    !>

    R

    !>          R is DOUBLE PRECISION array, dimension (LDA,MAX(M,N))
    !>

    LDA

    !>          LDA is INTEGER
    !>          The leading dimension of the arrays A, AF, R and Q.
    !>          LDA >= max(M,N).
    !>

    TAUA

    !>          TAUA is DOUBLE PRECISION array, dimension (min(M,N))
    !>          The scalar factors of the elementary reflectors, as returned
    !>          by DGGQRF.
    !>

    B

    !>          B is DOUBLE PRECISION array, dimension (LDB,P)
    !>          On entry, the N-by-P matrix A.
    !>

    BF

    !>          BF is DOUBLE PRECISION array, dimension (LDB,N)
    !>          Details of the GQR factorization of A and B, as returned
    !>          by DGGQRF, see SGGQRF for further details.
    !>

    Z

    !>          Z is DOUBLE PRECISION array, dimension (LDB,P)
    !>          The P-by-P orthogonal matrix Z.
    !>

    T

    !>          T is DOUBLE PRECISION array, dimension (LDB,max(P,N))
    !>

    BWK

    !>          BWK is DOUBLE PRECISION array, dimension (LDB,N)
    !>

    LDB

    !>          LDB is INTEGER
    !>          The leading dimension of the arrays B, BF, Z and T.
    !>          LDB >= max(P,N).
    !>

    TAUB

    !>          TAUB is DOUBLE PRECISION array, dimension (min(P,N))
    !>          The scalar factors of the elementary reflectors, as returned
    !>          by DGGRQF.
    !>

    WORK

    !>          WORK is DOUBLE PRECISION array, dimension (LWORK)
    !>

    LWORK

    !>          LWORK is INTEGER
    !>          The dimension of the array WORK, LWORK >= max(N,M,P)**2.
    !>

    RWORK

    !>          RWORK is DOUBLE PRECISION array, dimension (max(N,M,P))
    !>

    RESULT

    !>          RESULT is DOUBLE PRECISION array, dimension (4)
    !>          The test ratios:
    !>            RESULT(1) = norm( R - Q'*A ) / ( MAX(M,N)*norm(A)*ULP)
    !>            RESULT(2) = norm( T*Z - Q'*B ) / (MAX(P,N)*norm(B)*ULP)
    !>            RESULT(3) = norm( I - Q'*Q ) / ( M*ULP )
    !>            RESULT(4) = norm( I - Z'*Z ) / ( P*ULP )
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 174 of file dgqrts.f.

Author

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