What should be modified inside the for loop?

For each value of f_x_loop, I need x_a to take one of the five values from s_x_index for each iteration instead of one value for all the iteration.

 s_x_index=[0.01 0.02 0.03 0.04 0.05]
for  i = 1:length(s_x_index)
     x_a = s_x_index(i);
     f_x_loop = (F*x_a)/(s*Q)
     f_x_loop_save(i) = f_x_loop(i)
end

Please let me know if the given information is not sufficient.

Thanks

Answer 1

[Sara]

Change these lines:

f_x_loop = (F*x_a)/(s*Q)
f_x_loop_save(i) = f_x_loop(i)

into:

f_x_loop_save(i) = (F*x_a)/(s*Q)

in addition, put:

f_x_loop_save = zeros(numel(s_x_index),1);

before the for loop

[Priya]

I get this error.

 In an assignment  A(I) = B, the number of elements in B and I must be the same.

 Error in test_contact_ellipse (line 392)
     f_x_loop_save(i) = (F*x_a)/(s*Q)

[Sara]

what are the sizes of F, s, and Q?

[Joseph Cheng]

it also appears you need to do is

 x_a(i) = s_x_index(i);

or change the plot to be plot(s_x_index, f_x_loop_save, 'o') as you are overwriting x_a each time the loop occurs so when you plot you're plotting all f_x_loop_save at the last value of x_a from the loop.

[Joseph Cheng]

At the start before you do their suggestion just do mine. what i suggest will get it so that all your values are not for one value on the X axis.

what was originally suggested is good practice as you're doing an un-necessary temporary calculation (b=a then c=b, why not just c=a since you aren't using b anywhere) and initialization of the array for memory optimization (faster to fill in matrix than keep adding to the end of an array).

[Sara]

Try this:

f_x = (F.*s_x_index)/(s*Q);
figure(5);
plot(s_x_index, f_x, 'o')
xlabel('Longitudinal creepage');ylabel('coefficient of adhesion')
hold on;