diff options
Diffstat (limited to '2.3-1/src/fortran/blas/dcopy.f')
-rw-r--r-- | 2.3-1/src/fortran/blas/dcopy.f | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/2.3-1/src/fortran/blas/dcopy.f b/2.3-1/src/fortran/blas/dcopy.f new file mode 100644 index 00000000..e1689271 --- /dev/null +++ b/2.3-1/src/fortran/blas/dcopy.f @@ -0,0 +1,50 @@ + subroutine dcopy(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 |