c & " n",n," iposc",iposc,iposc+n-1
innt=chain_border(1,ichain)
inct=chain_border(2,ichain)
+c diagnostics
+c innt=chain_border(1,1)
+c inct=chain_border(2,1)
do i=innt,inct
vvec(ind+1)=v_work(j,i)
ind=ind+1
innt=chain_border(1,ichain)
inct=chain_border(2,ichain)
iposc=iposd_chain(ichain)
+c for debugging only
+c innt=chain_border(1,1)
+c inct=chain_border(2,1)
+c iposc=iposd_chain(1)
c write (iout,*)"stochastic_force ichain=",ichain," innt",innt,
c & " inct",inct," iposc",iposc
do j=1,3