i dont understand module.
- To: mathgroup at smc.vnet.net
- Subject: [mg46542] i dont understand module.
- From: sean_incali at yahoo.com (sean kim)
- Date: Sun, 22 Feb 2004 11:27:51 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
hello goup.
I just don't get this. this code was posted while back by Bob Hanlon.
All i did was to flank the routine by a module. i did so to minimize
memory used. I was hoping that by keepign things local, i can minimize
the resources used in the routine.
In[1]:=
Needs["Graphics`"];
Module[{},
sol=NDSolve[{a'[t]==-0.1` a[t] x[t], b'[t]==-0.05` b[t] y[t],
x'[t]==-0.1` a[t] x[t]+0.05` b[t] y[t],
y'[t]==0.1` a[t] x[t]-0.05` b[t] y[t],
a[0]==1,b[0]==1,x[0]==1,
y[0]==0}, {a,b,x,y},{t,0,250}][[1]]
Plot[Evaluate[#[[2]][t]& /@ sol],{t,0,250},
PlotStyle->Table[Hue[(k+1)/6],{k,4}], Frame->True,
Axes->False,
PlotLegend->(#[[1]]& /@ sol), LegendPosition->{1,-.35},
LegendShadow->{0, 0} , ImageSize->400];
]
above fails with the following error.
Plot::plnr: sol is not a machine-size real number at t = \
0.000010416666666666666`.
if i flank the module with Do loop, then I get recursion errors
In[5]:=
Needs["Graphics`"];
Do[
Module[{},
sol=NDSolve[{a'[t]==-0.1` a[t] x[t], b'[t]==-0.05` b[t] y[t],
x'[t]==-0.1` a[t] x[t]+0.05` b[t] y[t],
y'[t]==0.1` a[t] x[t]-0.05` b[t] y[t],
a[0]==1,b[0]==1,
x[0]==1,y[0]==0}, {a,b,x,y},{t,0,250}][[1]]
Plot[Evaluate[#[[2]][t]& /@ sol],{t,0,250},
PlotStyle->Table[Hue[(k+1)/6],{k,4}], Frame->True,
Axes->False,
PlotLegend->(#[[1]]& /@ sol), LegendPosition->{1,-.35},
LegendShadow->{0, 0} , ImageSize->400];
],
{iteration, 10}]
$RecursionLimit::reclim: Recursion depth of 256 exceeded.
what's going on here? and how do i fix it so that i can run it
automatically?
thanks all in advance.
sean