In this paper we consider inner parallelism of ODEs, and an approach t
o designing large scale parallelism for integrating ODEs. It is based
on vector field approximations by means of the complete integrable vec
tor field atlas. The maps of this atlas are in agreement with the defi
nition error of the original vector field which is changed on the loca
l map up to some complete integrable vector field. Potential paralleli
sm is associated with independent computations of the complete first i
ntegral system on each local map.