dcopy Subroutine

public subroutine dcopy(n, dx, incx, dy, incy)

copies a vector, x, to a vector, y. uses unrolled loops for increments equal to one.

Author

jack dongarra, linpack, 3/11/78.

Arguments

Type IntentOptional Attributes Name
integer, intent(in) :: n
real(kind=wp), intent(in) :: dx(*)
integer, intent(in) :: incx
real(kind=wp), intent(inout) :: dy(*)
integer, intent(in) :: incy

Called by

proc~~dcopy~~CalledByGraph proc~dcopy dvode_blas_module::dcopy proc~dacopy dvode_module::dacopy proc~dacopy->proc~dcopy proc~dvjac dvode_module::dvode_t%dvjac proc~dvjac->proc~dcopy proc~dvjac->proc~dacopy proc~dvnlsd dvode_module::dvode_t%dvnlsd proc~dvnlsd->proc~dcopy proc~dvnlsd->proc~dvjac proc~dvode dvode_module::dvode_t%dvode proc~dvode->proc~dcopy proc~dvstep dvode_module::dvode_t%dvstep proc~dvode->proc~dvstep proc~dvstep->proc~dcopy proc~dvstep->proc~dvnlsd

Source Code

    subroutine dcopy(n,dx,incx,dy,incy)

      implicit none

      integer,intent(in) :: n 
      real(wp),intent(in) :: dx(*) 
      integer,intent(in) :: incx 
      real(wp),intent(inout) :: dy(*)
      integer,intent(in) :: incy 

      integer :: i , ix , iy , m , mp1 

      if ( n<=0 ) return
      if ( incx==1 .and. incy==1 ) then

         ! code for both increments equal to 1

         ! clean-up loop

         m = mod(n,7)
         if ( m/=0 ) then
            do i = 1 , m
               dy(i) = dx(i)
            end do
            if ( n<7 ) return
         end if
         mp1 = m + 1
         do i = mp1 , n , 7
            dy(i) = dx(i)
            dy(i+1) = dx(i+1)
            dy(i+2) = dx(i+2)
            dy(i+3) = dx(i+3)
            dy(i+4) = dx(i+4)
            dy(i+5) = dx(i+5)
            dy(i+6) = dx(i+6)
         end do

      else

         ! code for unequal increments or equal increments
         ! not equal to 1

         ix = 1
         iy = 1
         if ( incx<0 ) ix = (-n+1)*incx + 1
         if ( incy<0 ) iy = (-n+1)*incy + 1
         do i = 1 , n
            dy(iy) = dx(ix)
            ix = ix + incx
            iy = iy + incy
         end do

      end if

    end subroutine dcopy