PRACE NPT

      Subroutine lsqslv( m, n, a, x )

! ----------------------------------------------------------------------

! --- lsqslv solves the rectangular upper diagonal system Ax = b in

!     the Least Squares sense: It is assumed that m <= n and

!     a(n,m) has only a non-zero upper triangle of order m.

!     On entry x contains the RHS. On exit it contains the

!     solution vector.

! ----------------------------------------------------------------------

      Use         numerics

      Use         floptime

      Implicit    None

      Integer  :: m, n

      Real(l_) :: a(n,m), x(m)

      Integer  :: i, j

      Real(l_) :: tmp

! ----------------------------------------------------------------------

      Do j = m, 1, -1

         x(j) = x(j)/a(j,j)

         tmp = x(j)

         Do i = j - 1, 1, -1

            x(i) = x(i) - tmp*a(i,j)

         End Do

      End Do

      flops = flops + ( m*( m + 1 ) )/2

! ----------------------------------------------------------------------

      End Subroutine lsqslv