Nested integral within integral2 in matlab

问题

I'm attempting to take the double integral (using integral2) of a function that is defined by an integral.

http://i.imgur.com/gIUsLSw.jpg

Here is what I am currently attempting:

t=linspace(0,1,50);
fun_1= @(v) exp(.071*v)
fun  = @(x,y) exp(0.14*0.00607*integral(@(u)fun_1(u),0,x)).*exp(-(x-y).^2).*exp(0.14*0.00607*integral(@(u)fun_1(u),0,x));
for i=2:length(t)
    for j=i:length(t)
    A(i,j)=integral2(fun,t(i-1),t(i),t(j-1),t(j));
    end
end

I'm receiving the error

Error using integral (line 86) A and B must be floating point scalars.

Can anyone provide any information on how to fix this problem.

回答1:

Here you go:

l=3;
t=linspace(0,1,365);
fun3= @(v) integral(@(v)exp(.071*v),0,v,'ArrayValued',true);
for i=2:length(t)
  for j=i:length(t)
      xx=t(i);
      yy=t(j);
      fun  = @(x,y) exp(0.14*0.00607*fun3(yy)).*exp(-(x-y).^2/l).*exp(0.14*0.00607*fun3(xx));
      y(i,j)=integral2(fun,t(i-1),t(i),t(j-1),t(j));
  end
end

It works, but it is very slow.

来源：https://stackoverflow.com/questions/18407385/nested-integral-within-integral2-in-matlab