what is wrong when using fzero

95 views (last 30 days)
Vicky
Vicky on 27 Feb 2013
hi!
i would like to compute this:
function z=theta(m)
digits 250;
s=sym('s');
p=0;
q=0;
for i=0:m
p=p+(factorial(2*m-i)*factorial(m)*s^i)/factorial(2*m)*factorial(m-
i)*factorial(i);
q=q+(factorial(2*m-i)*factorial(m)*(-s)^i)/factorial(2*m)*factorial(m-
i)*factorial(i);
end;
r=p/q;
s=taylor(exp(-s)*r-1, s, 150); %taylor expansion
coeff=vpa(sym2poly(sym(s)),250); % c_i
x=sym('x');
sum1=0;
l=1;
for j=(2*m+1):(150+2*m)
sum1=sum1+abs(coeff(l))*x^j;
l=l+1;
end;
bound=vpa((-log(1-sum1))/x,250);
n=fzero(bound,3);
just the last part is important. i think there is something wrong with my use of fzero.. when i want to calculate this, i get this error:
>> theta(2)
??? Error using ==> fzero at 181
If FUN is a MATLAB object, it must have an feval method.
Error in ==> theta at 27
n=fzero(bound,3);

Sign in to answer this question.

Answers (2)

Walter Roberson
Walter Roberson on 27 Feb 2013
You cannot use fzero() on symbolic objects.
If you are going to use symbolic objects, use solve(), or use
feval(symengine, 'numeric::solve', bound, 3)
  5 Comments
Show 3 older comments
Vicky
Vicky on 28 Feb 2013
or if i can use fsolve, where there is an initial point, what i would like. How to form that...

Sign in to comment.

Carlos
Carlos on 28 Feb 2013
You can use solve instead of fzero

Categories

Find more on Conversion in Help Center and File Exchange

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!