CODEWITHSUNDEEP
matlab
user3003027
user3003027

Reputation: 11

integral2 with fun calculated using vector

Im new to MATLAB. Want to use integral2 as follows 

function num = numer(x)
fun=@(p,w) prod((p+1-p).*(1-w).*exp(w.*x.*x/2))
num= integral2(fun ,0,1,0,1)
end

I get several errors starting with

Error using  .* 
Matrix dimensions must agree.

Error in numer>@(p,w)prod(p+(1-w).*exp(w.*x.*x/2)) (line 5)
fun=@(p,w) prod(p+(1-w).*exp(w.*x.*x/2))

Can you please tell me what I do wrong. Thanks

Upvotes: 0

Views: 203

Answers (1)

horchler
horchler

Reputation: 18504

From the help for integral2:

All input functions must accept arrays as input and operate
elementwise. The function Z = FUN(X,Y) must accept arrays X and Y of
the same size and return an array of corresponding values.

When x was non-scalar, your function fun did not do this. By wrapping everything in prod, the function always returned a scalar. Assuming that your prod is in the right place to begin with and taking advantage of the properties of the exponential, I believe this version will do what you need for vector x:

x = [0 1];
lx = length(x);
fun = @(p,w)(p+1-p).^lx.*(1-w).^lx.*exp(w).^sum(x.*x/2);
num = integral2(fun,0,1,0,1)

Alternatively, fun = @(p,w)(p+1-p).^lx.*(1-w).^lx.*exp(sum(x.*x/2)).^w; could be used.

Upvotes: 2

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