KTH framework for Nek5000 toolboxes; testing version  0.0.1
dscal.f
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1  subroutine dscal(n,da,dx,incx)
2 c
3 c scales a vector by a constant.
4 c uses unrolled loops for increment equal to one.
5 c jack dongarra, linpack, 3/11/78.
6 c modified 3/93 to return if incx .le. 0.
7 c modified 12/3/93, array(1) declarations changed to array(*)
8 c
9  double precision da,dx(*)
10  integer i,incx,m,mp1,n,nincx
11 c
12  if( n.le.0 .or. incx.le.0 )return
13  if(incx.eq.1)go to 20
14 c
15 c code for increment not equal to 1
16 c
17  nincx = n*incx
18  do 10 i = 1,nincx,incx
19  dx(i) = da*dx(i)
20  10 continue
21  return
22 c
23 c code for increment equal to 1
24 c
25 c
26 c clean-up loop
27 c
28  20 m = mod(n,5)
29  if( m .eq. 0 ) go to 40
30  do 30 i = 1,m
31  dx(i) = da*dx(i)
32  30 continue
33  if( n .lt. 5 ) return
34  40 mp1 = m + 1
35  do 50 i = mp1,n,5
36  dx(i) = da*dx(i)
37  dx(i + 1) = da*dx(i + 1)
38  dx(i + 2) = da*dx(i + 2)
39  dx(i + 3) = da*dx(i + 3)
40  dx(i + 4) = da*dx(i + 4)
41  50 continue
42  return
43  end
dscal
subroutine dscal(n, da, dx, incx)
Definition: dscal.f:2