I have a problem in writing the code for quad2d

Hi

Could anyone tell me what's the problem with this code:

 fun = @(x,y) (1./(2.* pi.* rint)) .* exp( - (x.^2 + y.^2)/(2.*rint)).*fint;

 Q = @(theta,r) fun(r.*cos(theta),r.*sin(theta)).*r;

 q = quad2d(Q,0,pi/2,0,rint);

rint is function based on a parameter that I want to estimate later.

Thanks

[Walter Roberson]

What problem are you observing ?

[Ferra]

It says:

Error using quad2d (line 124) D must be a finite, scalar, floating point constant or a function handle.

Error in myfunstar (line 51) q = quad2d(Q,0,pi/2,0,rint);

Answer 1

[Ferra]

Any idea? Please someone tell me what's the problem with this code!

I really appreciate it!

Answer 2

[Walter Roberson]

Your "rint" is not a finite scalar floating point constant or a function handle, and so is not value as the last parameter in quad2d()

Please show the content of rint. You mention it being a function: is it a function handle or is it the name of a function defined with "function ... = rint ..." ?

[Ferra]

Thank you for your response.The following is the code that I wrote and I want to minimize the function and estimate x (in another file I wrote the code for fminsearch). So you mean I should define rint as a function and bring it as a function handle as the last parameter in quad2d? But how?!

function f = myfunstar2(x,T,H,R)

p=1000; D=100;

lams=sqrt(x(1)*exp(-x(3)/(T)));

lamw=sqrt(x(2)*exp(-x(4)/(T)));

As = p^2 - (pi* (D^2) /4); d = 1000;

rint = lams + (D/2);

b = sqrt ((d.^2)+2.*(rint.^2)+rint.*(2.*D)+2.*(D.^2));

fint = (((2.*(asin (b ./2.*rint)./180).*(pi.*rint .^2) - (b .* d)./2)).^4) ./ (As .^ 4);

fun = @(x,y) (1./(2 .* pi .* rint)) .* exp( - (x.^2 + y.^2)/(2.*rint)).*fint;

Q = @(theta,r) fun(r.*cos(theta),r.*sin(theta)).*r;

q = quad2d(Q,0,pi/2,0,rint);

ks = 4 * ((pi*(rint^2))/pi* ((D^2)/4))* q *(((lams^2))/((D^2)/4));

kw=((pi*D*H)/(pi*(D^2)/4)*(lamw/H));

rate= ks+kw;

f = sum((rate - R)^2);

 end