Strange-nonchaotic-attractor-like behaviors in coupled map systems

In a coupled map system, an attractor which seems to be strange nonchaotic attractor (SNA) is discovered for nonzero measure in parameter range. The a ttractor has nonpositive Lyapunov exponent (LE) and discrete structure. We call it strange-nonchaotic-attractor-like (SNA-like) behavior because the s ize of its discrete structure decreases with the computing precision increa sing and the true SNA does not change. The SNA-Like behavior in the autonom ous system is born when the truncation error of round-off is amplified to t he size of the discrete part of the attractor during the long time interval of positive local LE. The SNA-like behavior is easily mistaken for a true SNA judging merely fi om the largest LE and the phase portrait in double pr ecision computing. In non-autonomous system an SNA-like attractor is also f ound.