Can I assign one element of a vector to a variable?

Hi everybody,

I have a question concerning my recent work. Isn't it possible to assign one element of a vector to a variable and get that saved in a cell array in a loop?

Later on I want to find the biggest element out of these and work with it. This is the error:

I also uploaded my code, as you can see the failure occures in line 219.

Here is a quick screenshot of the part of the code in case you don't need the full code.

Thank you very much for your help in advance, I'm a beginner at Matlab so thanks a lot everybody.

Johnny

Answer 1

[Ameer Hamza]

verschyl{allepunkte} is a row vector, whereas you are accessing it as a column vector. Reverse the order to correct the error. See the attached file. It should run without error.

[Jonathan Babitsch]

Thanks a lot Ameer, woulnd't have found that one..

Have a nice day sir,

Johnny

[Ameer Hamza]

I am glad to be of help.

[Jonathan Babitsch]

I have another simple question, would be nice if you could help me out. Can I find a max in a cell array? Like in my code now the max value in verschy1{allepunkte}? I get this error code if I try to do so:

Thanks a lot again in advance and I am sorry for wasting your time.

Johnny

[Ameer Hamza]

Is verschyl{allepunkte} a vector or scalar at this line of code? If it is a vector, then how many elements are in it? What is the value of allepunkte?

[Jonathan Babitsch]

Wow big thank you for your fast replying. I´m doing the step where I first needed your help to make it a scalar i guess so I extracted one element of the vector. Then afterwards i have it written in a cell array every iteration.

So it is a scalar. In the cell array there are some free cells, does that matter?

Here is a screenshot of what verschy1{allepunkte} looks like here:

And now I want the biggest element out here, that would be great. Thank you once again Ameer.

[Ameer Hamza]

Jonathan, you can try the following syntax to find the max of all the elements of the cell arrays

max([verschy1{:}])

I feel like what you are trying to do can be done quite easily in MATLAB with several if blocks. However, I don't understand the logic of your code. If the performance is fine for you and you understand the code, then you can continue using other; otherwise, you can attach a simple example of what you are trying to do in the first place. I will try to suggest a simple solution.

[Jonathan Babitsch]

Hi Ameer,

I did it with the if-blocks earlier.

However I tried your suggestion and it works for me as well.

As your code seems shorter and more simple I think I am going to use it. That´s pretty nice thanks a lot.

I really don´t know whether my code is clever or if there is a simpler way to do it. I started MATLAB because of my bachelors thesis and this is one of the parts I have to do within my project. Can I describe what I am working on? Are you willing to give it a thought?

I really don´t know whether this is common but is there a way of contacting you?

It is not ultimately necessary, given the fact that I at least have a solution now, even if it maybe isn´t the fastest and shortest. If you offer your help anyways I´ll gladly help it.

Big THANK YOU Ameer for your help this far, you really helped me getting forward with my work.

Have a nice evening!! (If it is evening in your place, I´m from germany :))

Jonathan

[Ameer Hamza]

Thanks!! I guess if it for a thesis, then execution speed might not be a critical requirement. It just needs to work to get the results. However, as a future reference, I recommend studying about vectorization in MATLAB and understanding the indexing in MATLAB. These are really powerful features that can help in writing code in just a few lines and avoid several if-else and for-loops. I wish you the best for your research.

[Jonathan Babitsch]

It´s not you are right, even though I´m doing it for a company where we are building a simulation together with Catia and the CFD. However one iteration takes like 18 seconds, which are peanuts compared to what the CFD is gonna take so I guess we are just fine. Thanks a lot for your advice Ameer, I will do some research there.

Once again thanks for your overall help, wouldn`t have made it without your advice today.

[Ameer Hamza]

I am glad to be of help!