How to implement a function within another one ?

Hi, I'd like to use the bisection method to find the root of a function "Fetoile" The method works but I have to iterate it for some values of a parameter "i". The problem is, the bisection function does not use "i".
Here is the code that gives me the results for "Fetoile" :
function Fetoile = q4(v)
% datas
vitesse_rotation= [83.7758040957278, 119.587013890941, 155.398223686155, 191.209433481369, 227.020643276582, 262.831853071796, 298.643062867009, 334.454272662223, 370.265482457437, 406.07669225265, 441.887902047864, 477.699111843078, 513.510321638291, 549.321531433505, 585.132741228718, 620.943951023932, 656.755160819146, 692.566370614359, 728.377580409573, 764.188790204786]
couple=[206.41064280052, 243.796265372056, 256.741969803922, 258.849308707433, 255.11836152428, 247.801181783381, 238.039957653591, 226.445249315901, 213.320493034029, 198.699623003111, 181.889713594511, 163.718280099678, 145.175662563345, 126.558747418095, 108.009552378088, 89.6025609484197, 71.3773301900352, 53.3538548851947, 35.5406860579882, 17.9395273160688]
rho=1.2;
S=2.28;
Cx=0.31;
mveh=1360;
g=9.81;
f0=0.0136;
f2=4.*10.^(-7);
ntrans=0.92;
atrans=1.04;
btrans=0.0025;
R=0.31;
i=[9.62,5.87,3.91,2.90,2.31];
teta=0;
%end of datas
for m = 1:5
Cmax=spline(vitesse_rotation,couple,i(m).*(v)/R);
Faero = (1/2)*rho*S*Cx*(v).^2;
Frlt = mveh*g*cos(teta)*(f0+f2*(v).^2);
Fgrav = mveh*g*sin(teta);
Fmotmax = ntrans*(i(m)/R)*Cmax;
Fetoile = Faero + Frlt + Fgrav - Fmotmax;
tabFetoile(m) = Fetoile;
end %end of for loop
disp('The results are :');
disp(tabFetoile);
And here is the code for the bisection, I tried a loop on the values of "vmin" are values that I'm sure are negatives.
function root = bishoz(f,vmin,vmax)
resultat = [];
for m = 1:5
vmin=[6,9.5,13.5,16.5,19];
vmax = 150;
fvmin(m) = f(vmin(m));
fvmax = f(vmax);
if fvmax*fvmin(m) > 0
disp('Valeurs de même signe.');
else
root = (vmax + vmin(m))/2;
err = abs(f(root));
end
while err > 1e-7
if fvmax*f(root)<0
vmin(m) = root;
else
vmax = root;
end %end of if
root = (vmax + vmin(m))/2;
err = abs(f(root));
end %end of while loop
resultat(m)=root;
end %end of for loop
disp(resultat);

 采纳的回答

I read through your example and it looks like the language functionality you are looking for are nested functions. Please see this for more info http://www.mathworks.com/help/matlab/matlab_prog/nested-functions.html

3 个评论

Thanks it seems like a good idea ! I was wondering something though.
When I call the function on MatLab, I have to call the first one, obviously. But in the help section, I don't find the syntax to make the first one call all the other. How should I write it ?
I do not understand what you are looking for Martin. Are you having problems calling the nested function from the outer main function?
It would help if you could provide a simple code example. That would help greatly. I have a feeling the answer you are looking for is close to hand. So please help us with a small example.
It is okay, I finally did by making a script which I looped 5 times and I used a function handle to call q4.

请先登录,再进行评论。

更多回答(1 个)

Sorry I read your code twice but got lost. Would you please epitomize your question by a simple example? Maybe it'll be a little better for other guys to get into this question..

1 个评论

I have a function that depends of "i" and "v" I have another function, bisecting the first one.
I want to make to make the bisection vary in terms of "i". But because the reach of "i" is only the first one, it doesn't work. It gives me 5 times the last value of "i".

请先登录,再进行评论。

类别

帮助中心File Exchange 中查找有关 Loops and Conditional Statements 的更多信息

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by