Why are the inputs to the functions used in the ODE45 solver not in the right syntax?

My code should solve an ODE that contains functions which are stored in seperate files. My problem is taht i dont know how to prperly give the inputs to the functions so it is transferred over several files. I was told i should try giving the additional inputs to the function when i call it rather than making the variables global (having the variables global worked the other option did not work yet). Should i keep it global or is the other approach also fine with the right syntax? And what is wrong about my code, that it doesnt work when trying to give the inputs to the function?

Thanks in advance.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%This is in thé main script:
field = [1,0,1 ; 1,1,1]; 
%in my script i loop through each element of the field-matrix and excute code afterwards but to make it easier to %understand i left that out since its not important for the question
idx1 = 1;
idx2 = 2;
startA  = 10;
A = 10;
currbugs = 12;

tspan = [0,1];
y0 = [startA];
[t,y]=ode45(@Aph,tspan,y0);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%This is the function which is in a seperate file:
function  sol=Aph(t,y,field,idx1,idx2,currbugs)
rgr = 10;
A = y(1);
P = (PRL1(field,idx1,idx2,A)*currbugs(2,1))+(PRad(field,idx1,idx2,A)*currbugs(7,1));
sol = rgr*A*(1-(A/2500))-P;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Within the calculation of the ODE45 equation other function PRL1 and PRad are called but they %are also  in seperate files:
function out = PRL1(field,idx1,idx2,A)
sr = 39.1;
ht = 10;
if field(idx1,idx2) == 1
    SAI = 1;
else
    SAI = 0.6;
end
out = (sr*(A/SAI))/(1+sr*ht*(A/SAI));
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%and the second function:
function out = PRad(field,idx1,idx2,A)
sr = 0.0139;
ht = 0.0049
if field(idx1,idx2) == 1
    SAI = 1;
else
    SAI = 0.6;
end
out = sr*(A/SAI)/(1+sr*ht*(A/SAI));

Answer 1

[Torsten]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%This is in thé main script:
field = [1,0,1 ; 1,1,1]; 
%in my script i loop through each element of the field-matrix and excute code afterwards but to make it easier to %understand i left that out since its not important for the question
idx1 = 1;
idx2 = 2;
startA  = 10;
A = 10;
currbugs = [1;1;1;1;1;1;7];
tspan = [0,1];
y0 = [startA];
[t,y]=ode45(@(t,y)Aph(t,y,field,idx1,idx2,currbugs),tspan,y0);
plot(t,y)

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%This is the function which is in a seperate file:
function  sol=Aph(t,y,field,idx1,idx2,currbugs)
rgr = 10;
A = y(1);
P = (PRL1(field,idx1,idx2,A)*currbugs(2,1))+(PRad(field,idx1,idx2,A)*currbugs(7,1));
sol = rgr*A*(1-(A/2500))-P;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Within the calculation of the ODE45 equation other function PRL1 and PRad are called but they %are also  in seperate files:
function out = PRL1(field,idx1,idx2,A)
sr = 39.1;
ht = 10;
if field(idx1,idx2) == 1
    SAI = 1;
else
    SAI = 0.6;
end
out = (sr*(A/SAI))/(1+sr*ht*(A/SAI));
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%and the second function:
function out = PRad(field,idx1,idx2,A)
sr = 0.0139;
ht = 0.0049;
if field(idx1,idx2) == 1
    SAI = 1;
else
    SAI = 0.6;
end
out = sr*(A/SAI)/(1+sr*ht*(A/SAI));
end

[Dominik Hüfner]

Hi thanks for the quick answer, in my code it is a vector 7x1 i just simplified the code and left out a lot of stuff to have a better overview for the people that are trying to help me.

currbugs = [1;1;1;1;1;1;7];

In the end my main question is how to give the inputs to the functions so that i dont have to use global variables for it. im talking about the following lines:

[t,y]=ode45(@(t,y)Aph(t,y,field,idx1,idx2,currbugs),tspan,y0);
function  sol=Aph(t,y,field,idx1,idx2,currbugs)
P = (PRL1(field,idx1,idx2,A)*currbugs(2,1))+(PRad(field,idx1,idx2,A)*currbugs(7,1));
function out = PRL1(field,idx1,idx2,A)
function out = PRad(field,idx1,idx2,A)

Im sorry for being a bit confusing with my question its the firts time im asking something in this forum. The difficulty is basicly the fact that there are functions called within a function and im not sure how to give the inputs to them.

[Torsten]

Works, doesn't it ?

(See above).

[Walter Roberson]

http://www.mathworks.com/help/matlab/math/parameterizing-functions.html

[Dominik Hüfner]

thanks for that link, that was the information i was looking for.