No plot in double integral

3 views (last 30 days)
Hexe
Hexe on 29 Jan 2023
Commented: Hexe on 30 Jan 2023
Hi! I try to solve the double integral, but there is an empty plot. Could you please tell me, what is wrong? In MathCad this integral is solved well.
n=1;
t=1;
r=1;
s=0:0.1:5;
fun = @(x,z,k) (x.*exp(2*n*t.*x.^2)./sqrt(1-x.^2)).*(exp(-2*t.*z.^2).*besselj(0,z.*k.*x).*(1+(sqrt(-pi)./(z*r)).*(1+((z*r).^2)/2).*(erfi(z*r/2)).*(exp(-((z*r).^2)/4))));
f3 = arrayfun(@(k)integral2(@(x,z)fun(x,z,k),0,Inf,0,1),s)
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
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Warning: The integration was unsuccessful.
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Warning: The integration was unsuccessful.
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Warning: The integration was unsuccessful.
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Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
Warning: Inf or NaN value encountered.
Warning: The integration was unsuccessful.
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Warning: The integration was unsuccessful.
f3 = 1×51
NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN
Cor = ((-2*r*sqrt(2*n*t)*exp(-2*n*t))/(pi*erf(sqrt(2*n*t))*(atan(r/(2*sqrt(2*t)))-sqrt(2*t)/(2*r*(1/4+2*t/(r^2))))))*f3;
plot(s,Cor,'g-');
  6 Comments
Walter Roberson
Walter Roberson on 29 Jan 2023
I did not notice that. I wonder what it would look like if you used sqrt(pi) instead?
n=1;
t=1;
r=1;
syms x z k s real
Pi = sym(pi);
fun = (x.*exp(2*n*t.*x.^2)./sqrt(1-x.^2)).*(exp(-2*t.*z.^2).*besselj(0,z.*k.*x).*(1+(sqrt(Pi)./(z*r)).*(1+((z*r).^2)/2).*(erfi(z*r/2)).*(exp(-((z*r).^2)/4))));
f3 = subs(int(int(fun,x,0,inf), z, 0, 1), k, s)
f3 = 
fun_zhalf = limit(subs(fun, k, 1), z, 1/2)
fun_zhalf = 
xlimited = limit(fun_zhalf, x, 1)
xlimited = 
case_to_plot = children(children(xlimited, 3),1)
case_to_plot = 
fplot(case_to_plot, [0 2])
xlimited = limit(fun_zhalf, x, 2)
xlimited = 
vpa(xlimited)
ans = 
You get rid of the real-valued portion of the function (at least at some values), but the complex portion remains.
Hexe
Hexe on 30 Jan 2023
Dear all, thank you for your replies. Yes, there is an imaginary part where sqrt(pi). And you are right, the integration is from 0 to 1 for x and 0-Inf for z. The math form is attached.

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