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call large equation to ode solver

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shahin hashemi
shahin hashemi on 5 Jun 2018
Commented: Torsten on 5 Jun 2018
dear all
i want solve equation with using ode113
clc
clear all
tic
initialcond=[-0.001,-0.001,-0.001,-0.001,-0.001,-0.001]
[T X]=ode113(@solver2link,[0 40],initialcond);
toc
this is my ode file and the following file is my equation
function dy = shebhestatici1(t,y)
X1=y(1,1);
X2=y(2,1);X3=y(3,1);X4=y(4,1);X5=y(5,1);X6=y(6,1);
M
G
xdd=inv(M)*(-G);
dy=xdd;
end
i calculate M and G from different file
previously M and G are short equation and i could copy theme directly to my ode solver
but now after some changes it become large file and i cant copy them
so my question is how could i call them to my ode solver for example :
function dy = shebhestatici1(t,y)
X1=y(1,1);
X2=y(2,1);X3=y(3,1);X4=y(4,1);X5=y(5,1);X6=y(6,1);
function M G
xdd=inv(M)*(-G);
dy=xdd;
end
i know its wrong but just to clear my point
thank you all

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Accepted Answer

Torsten
Torsten on 5 Jun 2018
function dy = shebhestatici1(t,y)
X1=y(1,1);
X2=y(2,1);
X3=y(3,1);
X4=y(4,1);
X5=y(5,1);
X6=y(6,1);
M = function_where_you_supply_M(X1,X2,X3,X4,X5,X6);
G = function_where_you_supply_G(X1,X2,X3,X4,X5,X6);
xdd=-M\G;
dy=xdd;
end

  5 Comments

Show 2 older comments
Torsten
Torsten on 5 Jun 2018
Make your code a function with output argments G and M and call it from where you need M and G.
shahin hashemi
shahin hashemi on 5 Jun 2018
i can change my code to a function but just with one output
function M = shebhestatici1
.
.
.
.
end
how should i do that for 2 ?
maybe like this ?
this doesnt work
function [M G] = shebhestatici1
and for last question should i put smth in front of shebhestatici1 ?
like :
function M = shebhestatici1(x)
Torsten
Torsten on 5 Jun 2018
https://de.mathworks.com/help/matlab/ref/function.html
In your case:
function [M,G] = shebhestatici1
If X1,...,X6 are needed to generate M and G,
function [M,G] = shebhestatici1(X1,X2,X3,X4,X5,X6)
Best wishes
Torsten.

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