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 is INTEGER


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



          M is INTEGER


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



          P is INTEGER


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



          A is DOUBLE PRECISION array, dimension (LDA,M)


          The N-by-M matrix A.



          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 is DOUBLE PRECISION array, dimension (LDA,N)


          The M-by-M orthogonal matrix Q.



          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 is DOUBLE PRECISION array, dimension (LDB,P)


          On entry, the N-by-P matrix A.



          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 is DOUBLE PRECISION array, dimension (LDB,P)


          The P-by-P orthogonal matrix Z.



          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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