Wrapping NDSolve within a function
- To: mathgroup at smc.vnet.net
- Subject: [mg126337] Wrapping NDSolve within a function
- From: bbeckage <Brian.Beckage at uvm.edu>
- Date: Thu, 3 May 2012 04:32:31 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
When I try to return the interpolating function produced by NDSolve from
within a function, the object returned has an unexpected $7360 appended,
e.g.,
out = predState[1.5, 0.4, 0.2, 0.1, 0.0002, 0.0099]
(where predState is defined further below) results in
=
{{g$7360->InterpolatingFunction[{{0.,1000.}},<>],p$7360->InterpolatingFunction[{{0.,1000.}},<>],q$7360->InterpolatingFunction[{{0.,1000.}},<>]}}
Note the g$7360 rather than just g. If NDSolve is not wrapped within
the function, it returns a plain 'g', i.e., g->InterpolatingFunction....
The appended $7360 makes it difficult to use the interpolating function
as I can't reference it within other functions as the integer changes
with each function call, e.g., g$7360[10] /. out, then g$7370[10] /.
out, rather than being able to access it using the expected g[10]/.out.
Why is this $7360 appended to g? How can NDSolve be wrapped in a
function, but be made to return a plain g?
Thanks for your help.
Best wishes,
Brian
predState[rg_, rp_, rh_, Mg_, Mp_, Mh_] :=
Module[{parmList3woC, parmListND3woC, A, B, Rb, Rc, g, p, q, solND},
parmListND3woC = {A -> Mg/rg, B -> Mp/rg, C -> Mh/rg, Rb -> rp/rg,
Rc -> rh/rg};
solND =
NDSolve[{
g'[t] == g[t]*(1 - g[t] - p[t] - q[t]) - A*g[t]*g[t] /. parmListND3woC,
p'[t] == Rb*p[t]*(1 - p[t] - q[t]) - B*p[t]*g[t] /. parmListND3woC,
q'[t] == Rc*q[t]*(1 - q[t]) - C*q[t]*g[t] /. parmListND3woC, g[0] == 0.5,
p[0] == 0.5, q[0] == 0.5}, {g, p, q}, {t, 0, 1000}];
Return[solND]
]