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| author | jofret | 2010-06-21 06:24:38 +0000 |
|---|---|---|
| committer | jofret | 2010-06-21 06:24:38 +0000 |
| commit | 8b44229ef44f0558ce045e46ff833fb44df913c9 (patch) | |
| tree | 4fdd89b2258c18c905d2f17ef4bea8ea9cf32893 /src/fortran/blas/ddot.f | |
| parent | af0366230e14cc75d9e9a183375ee9cb69fb46b6 (diff) | |
| download | scilab2c-release-2.0.tar.gz scilab2c-release-2.0.tar.bz2 scilab2c-release-2.0.zip | |
Tagging the 2.0 release of scilab2crelease-2.0
Diffstat (limited to 'src/fortran/blas/ddot.f')
| -rw-r--r-- | src/fortran/blas/ddot.f | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/src/fortran/blas/ddot.f b/src/fortran/blas/ddot.f new file mode 100644 index 00000000..e04c7c25 --- /dev/null +++ b/src/fortran/blas/ddot.f @@ -0,0 +1,49 @@ + double precision function ddot(n,dx,incx,dy,incy) +c +c forms the dot product of two vectors. +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(*),dtemp + integer i,incx,incy,ix,iy,m,mp1,n +c + ddot = 0.0d0 + dtemp = 0.0d0 + 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 + dtemp = dtemp + dx(ix)*dy(iy) + ix = ix + incx + iy = iy + incy + 10 continue + ddot = dtemp + return +c +c code for both increments 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 + dtemp = dtemp + dx(i)*dy(i) + 30 continue + if( n .lt. 5 ) go to 60 + 40 mp1 = m + 1 + do 50 i = mp1,n,5 + dtemp = dtemp + dx(i)*dy(i) + dx(i + 1)*dy(i + 1) + + * dx(i + 2)*dy(i + 2) + dx(i + 3)*dy(i + 3) + dx(i + 4)*dy(i + 4) + 50 continue + 60 ddot = dtemp + return + end |