Matlab Numerical integral improvement
6 visualizzazioni (ultimi 30 giorni)
Mostra commenti meno recenti
Hi, I have the integral below:
F_A_I=@(x) besselj(1,x.*3.5).*besselj(1,x.*0.5);
A=integral(F_A_I,0,Inf,'RelTol',1e-6,'AbsTol',1e-12,'ArrayValued',true);
But Matlab said:
Warning: Reached the limit on the maximum number of intervals in use. Approximate bound on error is 1.7e+00. The integral may not exist, or it may be difficult to approximate numerically to the requested accuracy.
while Mathematica can give the answer straightforward A=0.0205664
Could you please help me to improve my code. Thanks
1 Commento
Niels
il 4 Feb 2017
probably a definition gap in your function, integral might converge to inf, in these cases matlab displays -> Reached the limit on the maximum number of intervals in use.
Risposta accettata
Karan Gill
il 13 Feb 2017
Modificato: Karan Gill
il 17 Ott 2017
>> syms x
f = int(besselj(1, x/2)*besselj(1, (7*x)/2),x,0,inf)
f =
-(4*(100*ellipticE(1/49) - 99*ellipticK(1/49)))/(21*pi)
>> f_dbl = double(ans)
f_dbl =
0.0022
>> f_vpa = vpa(f)
f_vpa =
0.0022054352588140668793354496265733
OLD ANSWER from 13-Feb-2017
The convert to double using "double".
2 Commenti
Walter Roberson
il 14 Feb 2017
Modificato: Walter Roberson
il 14 Feb 2017
vpaintegral() with up to 10000 MaxFunctionCalls complains it cannot reach required precision.
The ratio oscillates a lot.
Più risposte (0)
Vedere anche
Categorie
Scopri di più su Calculus in Help Center e File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!