Return to saxpy.f CVS log

Up to [Research Unix] / researchv10no / cmd / view2d / num

Annotation of researchv10no/cmd/view2d/num/saxpy.f, revision 1.1.1.1

1.1       root        1:       subroutine saxpy(n,sa,sx,incx,sy,incy)
                      2: c
                      3: c     constant times a vector plus a vector.
                      4: c     uses unrolled loop for increments equal to one.
                      5: c     jack dongarra, linpack, 3/11/78.
                      6: c
                      7:       real sx(1),sy(1),sa
                      8:       integer i,incx,incy,ix,iy,m,mp1,n
                      9: c
                     10:       if(n.le.0)return
                     11:       if (sa .eq. 0.0) return
                     12:       if(incx.eq.1.and.incy.eq.1)go to 20
                     13: c
                     14: c        code for unequal increments or equal increments
                     15: c          not equal to 1
                     16: c
                     17:       ix = 1
                     18:       iy = 1
                     19:       if(incx.lt.0)ix = (-n+1)*incx + 1
                     20:       if(incy.lt.0)iy = (-n+1)*incy + 1
                     21:       do 10 i = 1,n
                     22:         sy(iy) = sy(iy) + sa*sx(ix)
                     23:         ix = ix + incx
                     24:         iy = iy + incy
                     25:    10 continue
                     26:       return
                     27: c
                     28: c        code for both increments equal to 1
                     29: c
                     30: c
                     31: c        clean-up loop
                     32: c
                     33:    20 m = mod(n,4)
                     34:       if( m .eq. 0 ) go to 40
                     35:       do 30 i = 1,m
                     36:         sy(i) = sy(i) + sa*sx(i)
                     37:    30 continue
                     38:       if( n .lt. 4 ) return
                     39:    40 mp1 = m + 1
                     40:       do 50 i = mp1,n,4
                     41:         sy(i) = sy(i) + sa*sx(i)
                     42:         sy(i + 1) = sy(i + 1) + sa*sx(i + 1)
                     43:         sy(i + 2) = sy(i + 2) + sa*sx(i + 2)
                     44:         sy(i + 3) = sy(i + 3) + sa*sx(i + 3)
                     45:    50 continue
                     46:       return
                     47:       end

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.