Re: A problem with derivative InterpolatingFunction from NDSolve
- To: mathgroup at smc.vnet.net
- Subject: [mg94755] Re: A problem with derivative InterpolatingFunction from NDSolve
- From: dh <dh at metrohm.com>
- Date: Tue, 23 Dec 2008 06:58:47 -0500 (EST)
- References: <giikd0$9nt$1@smc.vnet.net>
Hi Olfa,
I am running version 7 on Vista. That's the ouput I get:
alf= 1.
00 17559440
01 17553672
02 17569560
alf= 0.95
10 17433072
11 17416904
12 17429664
Memory seems to be pretty stable,
Faniel
bar at ANTYSPAM.ap.krakow.pl wrote:
> When i use an iteration with a derivative InterpolatingFunction
> Mathematica uses more than enough memory ( memory icreases in every steps)
>
> This is the sample:
> --------------
> For[jj = 0, jj < 2,
> alf = N[1 - jj/20];
> Print["alf= ", alf];
> dj = 1/200;
> For[j = 0, j < 3,
> ni = N[1.2 + j dj];
> start = 0;
> tmax = 4000;
> eq1 = u1''[t] + 5 alf u1[t] + ni u2[t] == 0;
> eq2 = u2''[t] + 3 u2[t] == 0;
> sol =
> NDSolve[{eq1, eq2, u1[0] == 1, u1'[0] == 0, u2[0] == 1,
> u2'[0] == 0}, {u1, u2}, {t, 0, tmax}, MaxSteps -> Infinity];
> U1[t_] := Evaluate[u1[t] /. sol][[1]];
> U2[t_] := Evaluate[u2[t] /. sol][[1]];
> F[t_] := U1[t] + U2[t];
> (*POINCARE ** ** ** ** **********)
> lista = {};
> start = 1500.;
> T = 2 Pi/ni;
> nt = 400;
> AppendTo[lista, {U1[100], U1'[100]}];
> Print[jj, j, " ", MemoryInUse[]];
> j++];
> jj++]
> ---------------------
>
> When I try U1[t] in place of U1'[t]
> everything's ok (MemoryInUse gives the same
> in all steps)
>
> Clear[u1,u2,U1,U2] doesn't help.
>
> Any suggestions ?
>
>
> Regards, Olaf
>
>
>
>
>