osse/EnKF/sscal.F

      subroutine sscal(n,sa,sx,incx)
c
c     scales a vector by a constant.
c     uses unrolled loops for increment equal to 1.
c     jack dongarra, linpack, 3/11/78.
c     modified 3/93 to return if incx .le. 0.
c
      real sa,sx(1)
      integer i,incx,m,mp1,n,nincx
c
      if( n.le.0 .or. incx.le.0 )return
      if(incx.eq.1)go to 20
c
c        code for increment not equal to 1
c
      nincx = n*incx
      do 10 i = 1,nincx,incx
        sx(i) = sa*sx(i)
   10 continue
      return
c
c        code for increment equal to 1
c
c
c        clean-up loop
c
   20 m = mod(n,5)
      if( m .eq. 0 ) go to 40
      do 30 i = 1,m
        sx(i) = sa*sx(i)
   30 continue
      if( n .lt. 5 ) return
   40 mp1 = m + 1
      do 50 i = mp1,n,5
        sx(i) = sa*sx(i)
        sx(i + 1) = sa*sx(i + 1)
        sx(i + 2) = sa*sx(i + 2)
        sx(i + 3) = sa*sx(i + 3)
        sx(i + 4) = sa*sx(i + 4)
   50 continue
      return
      end
1	subroutine sscal(n,sa,sx,incx)
2	c
3	c scales a vector by a constant.
4	c uses unrolled loops for increment equal to 1.
5	c jack dongarra, linpack, 3/11/78.
6	c modified 3/93 to return if incx .le. 0.
7	c
8	real sa,sx(1)
9	integer i,incx,m,mp1,n,nincx
10	c
11	if( n.le.0 .or. incx.le.0 )return
12	if(incx.eq.1)go to 20
13	c
14	c code for increment not equal to 1
15	c
16	nincx = n*incx
17	do 10 i = 1,nincx,incx
18	sx(i) = sa*sx(i)
19	10 continue
20	return
21	c
22	c code for increment equal to 1
23	c
24	c
25	c clean-up loop
26	c
27	20 m = mod(n,5)
28	if( m .eq. 0 ) go to 40
29	do 30 i = 1,m
30	sx(i) = sa*sx(i)
31	30 continue
32	if( n .lt. 5 ) return
33	40 mp1 = m + 1
34	do 50 i = mp1,n,5
35	sx(i) = sa*sx(i)
36	sx(i + 1) = sa*sx(i + 1)
37	sx(i + 2) = sa*sx(i + 2)
38	sx(i + 3) = sa*sx(i + 3)
39	sx(i + 4) = sa*sx(i + 4)
40	50 continue
41	return
42	end