Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.



Problem with discontinuity in NDSolve[]
Posted:
Jun 26, 1996 3:09 AM


Hi everybody,
I have a problem with NDSolve if my equation contains a discontinuity. If I try
NDSolve[{y'[t] == 10  y[t] * If[y[t]15 <= 0, 0, 1], y[0] == 0}, y, {t,0,20}]
I always get the error: Maximum number of steps reached. The solution should be a linear increase until y = 15 followed by an exponential decay until a steady state is reached by y = 10
Funny enough if I try
NDSolve[{y'[t] == 10  y[t] * If[t15 <= 0, 0, 1], y[0] == 0}, y, {t,0,20}]
causing the discontinuity to be at t = 15 instead of y = 15 NDSolve has no problems at all. (But of course this is not what I want.)
ANY SOLUTIONS ??? ANY IDEAS ???
Many thanks
Axel Kowald
P.S. I'm using Mma 2.2 on a Mac with 7.5.3 and 24 MB RAM



