Calculation of distance automatically at height h and from point O for different curve

Hi all,

I hope you are doing well in this pandemic. I am new at Matlab, and i would like to solve one problem, which i am thinks very difficult to solve with the Matlab. I have one formula which calculates the curve at different K value. I need to evaluate the value of X1 , X2, X3 , X4, , X5, and X6 at height "H" from point "O" automatically for further condition. How can i caculate automatically by algorithm and use those different X1 , X2, X3 , X4, , X5 and X6 value in further algorithm. (For explnation, You can see it in the picture and you willl understand it much better)

My mind is stopped working for this, so any ray of light from you guys will be highly appreciable.

Thanks a ton

Jenny Lee

Answer 1

[Image Analyst]

Isn't it just

% Find the index where the curve, for some particular k value, first drops below -0.05.
index = find(kCurve < -0.05, 1, 'first');
% Use that index to get the x value where the curve first drops below -0.05.
xN = x(index);

[Image Analyst]

Do you want to find the nearest existing point, or do you need to interpolate between existing points?

[Image Analyst]

The blue horizontal lines are shown in the image. Their lengths are given by the deltax variable.

I had 2 particles in your program so there are 2 lines, not 26 or 52.

I picked an absolute value for h since the bottom y limit depends on the size of the figure and it doesn't make sense to go up 0.04 from some arbitrary, variable y value.

[Devyani Sankhe]

@Jenny Lee, @Image Analyst I am also interested in this solution, have you solved the problem? Because my problem is same but different context. Tell me, if you find the solution.

[Image Analyst]

So I did this:

V_new = 10; %30e3; % set range here(from 10 to 40)

and I get this, where both particles are overlapped and deltax has two values that are the same.

[image snipped] at request of Mathworks.

[Image Analyst]

Please just give me the program.

When I do

V_new = [10 : 40]; %30e3; % set range here(from 10 to 40)

it throws an error.

[Image Analyst]

Jenny:

Again, please just attach your program. That V_new doesn't work, and if it did, you still have only 2 particles.

Maybe you need to have a loop over V_new.

[Jenny Lee]

@Image Analyst I did not understand, can you tell me loop over means ? I tried multiple way but it did not work. Thats why i am asking to you.

Thanks a lot

[Devyani Sankhe]

@Image Analyst , I believe, she want the different curve at V_new value , similar way i wanted to implement this concept. @Jenny Lee?

[Jenny Lee]

@Jenny Lee , you are right, i want different curve at V_new value. But the code shows error and i do not know where is the problem. I hope on the @Image Analyst, whether it is possible to solve the problem or not.

[Image Analyst]

Once you manage to get the curve you want, the code I added to your plotting function should find the delta X for all the existing curves.

Maybe you just need to have a for loop over different V_new.

[Jenny Lee]

@Image Analyst, how can do loop over different value , That is the problem i am facing. Please can you tell me how to do it ?

I am having bad time to do it, please help me

Many thanks

Jenny

[Devyani Sankhe]

How to do it loop over different value ? @Image Analyst

[Jenny Lee]

@Image Analyst, any idea to perform loop so it can plot the multiple curve ???

Thanks

Jenny

[Image Analyst]

Jenny, not all your discrete particle locations are at the Point A y value. I check the first one that goes lower than that. If you want one exactly at that exact y value you'd have to interpolate the x and y values to get a new point at the exact level as point A. Is this precision necessary? Is that what you want to do? Because it will add come complexity, only a few lines though.

[Image Analyst]

I think it's within your abilities, nonetheless I'm working on it now.

[Image Analyst]

OK, I think I've got it, though I've spent way more time for you than I usually spend for people, but you're just so nice. 🙂

[image snipped] at request of Mathworks.