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real function da_dot(n,x,y) 4,2
!-----------------------------------------------------------------------
! Purpose: forms the dot product of two vectors.
! uses unrolled loops for increments equal to one.
!-----------------------------------------------------------------------
implicit none
integer, intent(in) :: n
real, intent(in) :: x(n)
real, intent(in) :: y(n)
real :: dtemp1
integer :: i,m,mp1
da_dot = 0.0
if (n <= 0) return
if (trace_use) call da_trace_entry
("da_dot")
dtemp1 = 0.0
! code for both increments equal to 1
if (n > 0) then
m = mod(n,5)
if (m /= 0) then
do i = 1,m
dtemp1 = dtemp1 + x(i)*y(i)
end do
end if
if (n >= 5) then
mp1 = m + 1
do i = mp1,n,5
dtemp1 = dtemp1 + x(i )*y(i ) + x(i + 1)*y(i + 1) + &
x(i + 2)*y(i + 2) + x(i + 3)*y(i + 3) + &
x(i + 4)*y(i + 4)
end do
end if
end if
da_dot = dtemp1
if (trace_use) call da_trace_exit("da_dot")
end function da_dot