Bisection method help.

function [f] = Bisection(a, b, Nmax, TOL);
  f=@(x) x.*x.*x.-2;
  i=1;
  BisectA = f(a)
  while i <= Nmax
    p=a+(b-a)/2;
    BisectP=f(p);
    if BisectP == 0 || (b-a)/2 < TOL
      disp('p');
    endif
    i = i+1;
    if BisectA*BisectP > 0
      a = p;
      BisectA = BisectP;
    else
      b = p;
    endif
  end
  fprintf('method failed after %d iterations\n', Nmax);
  endfunction

After entering four numerical values this is the output I'm recieving.

Bisection(2, 4, 6, 8)
BisectA =  6
p
p
p
p
p
p
method failed after 6 iterations
ans =

@(x) x .* x .* x - 2

Is this correct?

Answer 1

[Asad (Mehrzad) Khoddam]

function x = Bisection(a, b, Nmax, TOL)
f=@(x) x.*x.*x-2;
i=1;
ya = f(a);
while i <= Nmax
    m=(a+b)/2;
    ym=f(m);
    if ym == 0 || (b-a)/2 < TOL
        disp(m);
        break;
    end
    i = i+1;
    if ya*ym > 0
        a = m;
        ya = ym;
    else
        b = m;
    end
end
if i==Nmax
    fprintf('method failed after %d iterations\n', Nmax);
    x=NaN;
else
    x=m;
end