dgqrts.f - Man Page

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

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.