How to integrate a symbolic function?
2 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Max
am 22 Jan. 2016
Kommentiert: Max
am 23 Jan. 2016
Hello,
I´m trying to integrate a symolic expression. Therefore I use the MATLAB command "int". But the problem is that it seems like Matlab doesn´t calculate that integral. If I try to convert the result into a numeric number: double(result) then I will get an error.
Could somebody help me, please?
This is my code:
tfail = [5571.760,5573.742,5654.457]
n = length(tfail)
beta_hat = 4.2915822
B_hat = 1861.6186657
C_hat = 58.9848692
syms t B beta C
y(t) = (exp(-B_hat/((heaviside(t)-heaviside(t-2000))*(330)+(heaviside(t-2000)-heaviside(t-3000))*(350)+...
(heaviside(t-3000)-heaviside(t-14000))*(390))))/C_hat;
logL=0;
for i=1:n
tfail(i)
I(i) = int(y(t),t,0,tfail(i))
y_new(i)=subs(y,t,tfail(i))
logL =logL+log((beta*y_new(i)*(I(i))^(beta-1))*exp(-((I(i))^beta)))
end
PS: for i=1, I should get for the integral I(t=5571.76)=0.57185
0 Kommentare
Akzeptierte Antwort
Walter Roberson
am 23 Jan. 2016
You have subs(y,t,tfail(i)) when y is a function. You invoke functions on values, not subs() the values.
y_new(i) = y(tfail(i))
Weitere Antworten (0)
Siehe auch
Kategorien
Mehr zu Symbolic Math Toolbox finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!