Re: System of ODE
- To: mathgroup at smc.vnet.net
- Subject: [mg42064] Re: System of ODE
- From: "Amedeo" <wallpeer at libero.it>
- Date: Tue, 17 Jun 2003 05:44:18 -0400 (EDT)
- References: <bcjtaj$hlt$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
> NDSolve doesn't understand equations in matrix form, primarily because
> Equal isn't Listable.
>
> Here's the form you need:
>
> NDSolve[Flatten[Thread /@ {A'[t] == M[t].A[t] + 2*C, A[0] == {0, 0}}],
> A[t], {t, 0, 300}]
>
> Note that you can't use D as a variable name, and matrix multiplication
> is done with Dot, not *. And with such a long time interval, you'll
> likely need to use the MaxSteps option.
>
> -----
solution=NDSolve[Flatten[Thread/@{B'[t]\[Equal]A[t].B[t],B[0]\[Equal]{0,0}}]
,
B[t],{t,0,300}]
NDSolve::ndnco: The number of constraints (2) (initial conditions) is not \
equal to the total differential order of the system (1).
NDSolve::ndnco: The number of constraints (2) (initial conditions) is not \
equal to the total differential order of the system (1).
why this problem?