Per the help document for ODE23/45, there is no way to get a 2-element solution even if I input tspan which has only 2 points (my tspan is like 1+1/500:1/500:1+2/500). So my question is if
1. I can enforce ODE solvers to yield such solutions or
2. is there any alternative ODE routine that I can use to get my things working?