Compute a minimum-norm solution


     min || A*X - B ||


 using the RQ factorization


     A = R*Q


 computed by DGERQF.

M

          M is INTEGER


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

N

          N is INTEGER


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

NRHS

          NRHS is INTEGER


          The number of columns of B.  NRHS >= 0.

A

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


          Details of the RQ factorization of the original matrix A as


          returned by DGERQF.

LDA

          LDA is INTEGER


          The leading dimension of the array A.  LDA >= M.

TAU

          TAU is DOUBLE PRECISION array, dimension (M)


          Details of the orthogonal matrix Q.

B

          B is DOUBLE PRECISION array, dimension (LDB,NRHS)


          On entry, the right hand side vectors for the linear system.


          On exit, the solution vectors X.  Each solution vector


          is contained in rows 1:N of a column of B.

LDB

          LDB is INTEGER


          The leading dimension of the array B. LDB >= max(1,N).

WORK

          WORK is DOUBLE PRECISION array, dimension (LWORK)

LWORK

          LWORK is INTEGER


          The length of the array WORK.  LWORK must be at least NRHS,


          and should be at least NRHS*NB, where NB is the block size


          for this environment.

INFO

          INFO is INTEGER


          = 0: successful exit


          < 0: if INFO = -i, the i-th argument had an illegal value

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.