Re: NDSolve problem
- To: mathgroup at christensen.cybernetics.net
- Subject: [mg912] Re: NDSolve problem
- From: saarinen (Sirpa Saarinen)
- Date: Sun, 30 Apr 1995 03:46:37 -0400
- Organization: Wolfram Research, Inc.
In <3nkcth$n02 at news0.cybernetics.net> pitts at mayo.EDU (Todd Pitts) writes:
>Changing the coefficient 4.0 in eq to unity (1 not 1.0) gives no error. Also
>writing the equation as
>eq={D[x[1][t],{t,2}]==(x[1][t]-Sin[t])/4};
>works. If I don't use subscripted variables I don't have this problem. For
>example
>sys2 = sys /. x[1] -> x
>NDSolve[sys2,x,{t,0,10}]
>seems to work fine. I would greatly appreciate any hints. Is this a bug or
>have I misunderstood the use of subscripted variables? The version number is
>2.2. I get the same behavior on NeXT and DEC Alfa.
The current version V2.2 of NDSolve does not support indexed variables,
so you could use something like
Out[6]= {x''[t] == -Sin[t] + x[t], x'[0] == 0, x[0] == 0}
In[7]:= In[7]:= NDSolve[sys,x,{t,0., 10.}]
Out[7]= {{x -> InterpolatingFunction[{0., 10.}, <>]}}
In the version under development most N* functions in mathematica will
be supporting also indexed variables.
Sirpa Saarinen
saarinen at wri.com