I am tyring to implement a code with a loop. But my output variable is a NaN, but it must be a number in output. I am not sure what's wrong. Can anyone help?

a = (D1/2)-(D2_cor/2) % the major axis the ellipse - ??

b = a*0.75

ellipse = [a,b]

ellipse_length = 0 % inlitialize integral

integral_start = 0 % Integrate from ...

ns = 18 % number of streamlines

np = 40 % number of points per streamlines

% Integrate to end of ellipse , minus a small part to avoid infinite integral. ..??

integral_end = ellipse(1) - 0.0001

integral_step = 100000 % integral step

dx = (integral_end - integral_start)/integral_step % initializing dx

%now we make integral start to find the length of the ellipse along ring

for x = integral_start : dx : integral_end

dydx = (1/2)*ellipse(2)*(1-(x/ellipse(1)^2)^(-0.5))*(-(2*x/(ellipse(1)^2)));

ellipse_length = ellipse_length + sqrt(1+(dydx)^2)*dx;

end

% here the output in the variable "ellipse_length" is a NaN. I don't know whats wrong. Can anyone suggest me what is wrong here?

[KSSV]

Check the formula for dydx...this is giving -inf....you need to check the brackets and power. Are they correctly represented?

[ravi poudel]

Thanks for the suggestion KSSV

Answer 1

[Sam Chak]

@ravi poudel

Please check your code if singularity occurs in this line:

dydx = (1/2)*ellipse(2)*(1-(x/ellipse(1)^2)^(-0.5))*(-(2*x/(ellipse(1)^2)));

[ravi poudel]

thanks