| subroutine dcopyf(n,dx,incx,dy,incy) |
| c |
| c copies a vector, x, to a vector, y. |
| c uses unrolled loops for increments equal to one. |
| c jack dongarra, linpack, 3/11/78. |
| c modified 12/3/93, array(1) declarations changed to array(*) |
| c |
| double precision dx(*),dy(*) |
| integer i,incx,incy,ix,iy,m,mp1,n |
| c |
| if(n.le.0)return |
| if(incx.eq.1.and.incy.eq.1)go to 20 |
| c |
| c code for unequal increments or equal increments |
| c not equal to 1 |
| c |
| ix = 1 |
| iy = 1 |
| if(incx.lt.0)ix = (-n+1)*incx + 1 |
| if(incy.lt.0)iy = (-n+1)*incy + 1 |
| do 10 i = 1,n |
| dy(iy) = dx(ix) |
| ix = ix + incx |
| iy = iy + incy |
| 10 continue |
| return |
| c |
| c code for both increments equal to 1 |
| c |
| c |
| c clean-up loop |
| c |
| 20 m = mod(n,7) |
| if( m .eq. 0 ) go to 40 |
| do 30 i = 1,m |
| dy(i) = dx(i) |
| 30 continue |
| if( n .lt. 7 ) return |
| 40 mp1 = m + 1 |
| do 50 i = mp1,n,7 |
| dy(i) = dx(i) |
| dy(i + 1) = dx(i + 1) |
| dy(i + 2) = dx(i + 2) |
| dy(i + 3) = dx(i + 3) |
| dy(i + 4) = dx(i + 4) |
| dy(i + 5) = dx(i + 5) |
| dy(i + 6) = dx(i + 6) |
| 50 continue |
| return |
| end |
