define a function which computes numerical integral

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giorgione palma
giorgione palma 2017-4-13
评论： Torsten 2017-4-13
Given 2 function f=@(x),g=@(x) I would like to define the function cg1return =@(t) int(f(s) * int(g(z), z == (0..s)), s == (0..t)) which gives to me the the result of the numeric integral from 0 to t. In other words it takes as input the extreme of integration "t" and gives me back the result of this nasty double integral.

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回答（1 个）

Torsten
Torsten 2017-4-13
function main
t = ...;
cg1return = integral(@fun,0,t);
function y = fun(s)
f = @(s)...;
g = @(z)...;
for i=1:numel(s)
y(i) = f(s(i))*integral(g,0,s(i));
end
But my first solution was much more efficient :-)
Best wishes
Torsten.
  2 个评论
giorgione palma
giorgione palma 2017-4-13
Thank you, but I don't understand how are the function @fun and the vector "s" defined.
Torsten
Torsten 2017-4-13
@fun is defined as a function routine which is below the call "cg1return = integral(@fun,0,t);"
The vector s does not need to be defined by you. You only have to fill in the functions f and g and the end point t of integration.
Best wishes
Torsten.

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