1      real function sdot(n,sx,incx,sy,incy)
2c
3c     forms the dot product of two vectors.
4c     uses unrolled loops for increments equal to one.
5c     jack dongarra, linpack, 3/11/78.
6c     modified 12/3/93, array(1) declarations changed to array(*)
7c
8      real sx(*),sy(*),stemp
9      integer i,incx,incy,ix,iy,m,mp1,n
10c
11      stemp = 0.0e0
12      sdot = 0.0e0
13      if(n.le.0)return
14      if(incx.eq.1.and.incy.eq.1)go to 20
15c
16c        code for unequal increments or equal increments
17c          not equal to 1
18c
19      ix = 1
20      iy = 1
21      if(incx.lt.0)ix = (-n+1)*incx + 1
22      if(incy.lt.0)iy = (-n+1)*incy + 1
23      do 10 i = 1,n
24        stemp = stemp + sx(ix)*sy(iy)
25        ix = ix + incx
26        iy = iy + incy
27   10 continue
28      sdot = stemp
29      return
30c
31c        code for both increments equal to 1
32c
33c
34c        clean-up loop
35c
36   20 m = mod(n,5)
37      if( m .eq. 0 ) go to 40
38      do 30 i = 1,m
39        stemp = stemp + sx(i)*sy(i)
40   30 continue
41      if( n .lt. 5 ) go to 60
42   40 mp1 = m + 1
43      do 50 i = mp1,n,5
44        stemp = stemp + sx(i)*sy(i) + sx(i + 1)*sy(i + 1) +
45     *   sx(i + 2)*sy(i + 2) + sx(i + 3)*sy(i + 3) + sx(i + 4)*sy(i + 4)
46   50 continue
47   60 sdot = stemp
48      return
49      end
50