stdlib_dscal Subroutine

     pure subroutine stdlib_dscal(n,da,dx,incx)
     !! DSCAL scales a vector by a constant.
     !! uses unrolled loops for increment equal to 1.
        ! -- reference blas level1 routine --
        ! -- reference blas is a software package provided by univ. of tennessee,    --
        ! -- univ. of california berkeley, univ. of colorado denver and nag ltd..--
           ! Scalar Arguments 
           real(dp), intent(in) :: da
           integer(ilp), intent(in) :: incx, n
           ! Array Arguments 
           real(dp), intent(inout) :: dx(*)
        ! =====================================================================
           ! Local Scalars 
           integer(ilp) :: i, m, mp1, nincx
           ! Intrinsic Functions 
           intrinsic :: mod
           if (n<=0 .or. incx<=0) return
           if (incx==1) then
              ! code for increment equal to 1
              ! clean-up loop
              m = mod(n,5)
              if (m/=0) then
                 do i = 1,m
                    dx(i) = da*dx(i)
                 end do
                 if (n<5) return
              end if
              mp1 = m + 1
              do i = mp1,n,5
                 dx(i) = da*dx(i)
                 dx(i+1) = da*dx(i+1)
                 dx(i+2) = da*dx(i+2)
                 dx(i+3) = da*dx(i+3)
                 dx(i+4) = da*dx(i+4)
              end do
           else
              ! code for increment not equal to 1
              nincx = n*incx
              do i = 1,nincx,incx
                 dx(i) = da*dx(i)
              end do
           end if
           return
     end subroutine stdlib_dscal