octave: libcruft/arpack/util/iswap.f comparison

import ARPACK sources to libcruft from Debian package libarpack2 2.1+parpack96.dfsg-3+b1

comparison

equal deleted inserted replaced

-:83133b5bf392
+:9f5d2ef078e8
+subroutine iswap (n,sx,incx,sy,incy)
+c
+c     interchanges two vectors.
+c     uses unrolled loops for increments equal to 1.
+c     jack dongarra, linpack, 3/11/78.
+c
+integer sx(1),sy(1),stemp
+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 not equal
+c         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
+stemp = sx(ix)
+sx(ix) = sy(iy)
+sy(iy) = stemp
+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,3)
+if( m .eq. 0 ) go to 40
+do 30 i = 1,m
+stemp = sx(i)
+sx(i) = sy(i)
+sy(i) = stemp
+30 continue
+if( n .lt. 3 ) return
+40 mp1 = m + 1
+do 50 i = mp1,n,3
+stemp = sx(i)
+sx(i) = sy(i)
+sy(i) = stemp
+stemp = sx(i + 1)
+sx(i + 1) = sy(i + 1)
+sy(i + 1) = stemp
+stemp = sx(i + 2)
+sx(i + 2) = sy(i + 2)
+sy(i + 2) = stemp
+50 continue
+return
+end

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