Re: NDSolve doesn't stop
- To: mathgroup at smc.vnet.net
- Subject: [mg74358] Re: NDSolve doesn't stop
- From: bar at ANTYSPAM.ap.krakow.pl
- Date: Mon, 19 Mar 2007 05:52:43 -0500 (EST)
- Organization: Akademia Pedagogiczna w Krakowie
- References: <etikd4$j5c$1@smc.vnet.net> <etlchi$nrv$1@smc.vnet.net>
Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com> wrote: > > notebook file is "not readable" so I put it on www > > http://robox.ap.krakow.pl/~bar/pde.nb > tmax = 20 ==> no warning message issued (indeed for any 0 < tmax <) > tmax = 21 ==> a warning message is issued: it might be worth reading it > ========= > NDSolve::"eerr" : "Warning: Scaled local spatial error estimate of > (159.0346060966196) at (t) = (21.) in the direction of independent > variable (x) is much greater than prescribed error tolerance. Grid > spacing with (15) points may be too large to achieve the desired > accuracy or precision. A singularity may have formed or you may want to > specify a smaller grid spacing using the MaxStepSize or MinPoints > options. More... There is a problem, I can't see this message, message window i empty, noetebook i running continuously, without any message too, (Mathematica 5.1 Linux localhost 2.6.19-gentoo-r5 #10 SMP PREEMPT Tue Feb 20 21:34:30 CET 2007 i686 Intel(R) Pentium(R) 4 CPU 3.00GHz GenuineIntel GNU/Linux) top shows 0%CPU, 0%Memory When i try MaxStepSize->0.001 thet top shows 99%CPU and %MEM is growing up to 100% (in about 5 minutes) and %CPU decreases to 0% In this time I killed process ... There is a problem with my individual installation ? The system of equations is not difficult, without nonlinearity, I can solve it "hand-made" , by reduction to ODE equation by separation t/x variable I decided to use Math because i hoped to see solution in addition nonlinearity ... Regards , Olaf