Passing Functions and m-files to functions

Hi Mathworks,

I have an m-file which codes up a system of differential equations;

9D_system

This has various parameters in it, and I have a few parameter schemes for specifying the values to these parameters;

P1.m, P2.m, P3.m

I want to be able to specify which parameter scheme I endow the system with, and then solve this system of differential equations with ode15s.

How do I do this?

Moreover, the parameter schemes

P1.m, P2.m, P3.m

each call functions (some of the parameters are functions of other parameters, and so must be calculated by these called functions). Thus the ode will have a series of nested functions being called!!

Any help on this would be greatly appreciated. :)

Linford

[José-Luis]

Pass them as a string and evaluate inside your function.

Answer 1

[Sean de Wolski]

@Linford, these are the ways we recommend passing extra parameters:

http://www.mathworks.com/help/releases/R2012b/optim/ug/passing-extra-parameters.html

e.g:

ode45(@(t,y)myfun(t,y,@p1)

And

function x = myfun(t,y,pfun)

stuff = pfun(); 

x = do_things_with(stuff,t,y)

[Jan]

Or add the parameters as additional arguments to the anoymous function directly. See also: http://www.mathworks.de/matlabcentral/answers/1971

Answer 2

[Azzi Abdelmalek]

f=@P1
f=@P2

Answer 3

[José-Luis]

myStr = 'P1.m'

function [result] = myFun(someArg, myStr)
    [str str] = fileparts(myStr);
    run(str); %calling your script
    %Do your thing

[Linford Briant]

Hi Jose-Luis,

Thanks for this; it works a treat for my parameter functions, but it isn't working for my ODE files. For example, the following is the first 4 lines of a file making my ODE file.

function xprime = 9D_system(t,x,myStr,L)
    [str str] = fileparts(myStr);
    run(str); %calling your script
    %Do your thing

When I call this in MATLAB I get the error:

[t,x] = ode15s(@(t,x) 9D_system(t,x,myStr,0.001),[0 2e6],x0);
??? Input argument "myStr" is undefined.

Even though I have previously defined

myStr='Parameter1.m'