# About the use of find

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A on 23 Aug 2021
Commented: A on 23 Aug 2021
I want to detect values greater than 10 and get their indices.
In my case, I'm using find to get the index as follows.
y = find( x > 10 );
I think find is finding the value greater than 10 in all elements of x and getting the index.
So I have a question.
Does find start computing at the moment when all the elements of x are given, rather than at the moment when any element of x is given?
I would like to perform the computation at the moment when even one element of x is given, do the same process as find, get the same index, and store it in the same way.
In that case, what kind of program should I write? It would be great if you could post your program.
A on 23 Aug 2021
Dear　Stephen Cobeldick
I learned that find returns the linear/subscript index of the logical array.
If I want to get the linear/subscript index of a logical array, is there any other way than find?
I am sorry that my questions are poorly written and difficult to understand.
"Does find start computing at the moment when all the elements of x are given, rather than at the moment when any element of x is given"
Regarding the above question...
In this case, we run Simulink and consider the data to be acquired in real time as x.
In this case, does find calculate the value of x in real time?
Or does it start calculating after the Simulink simulation is finished and all the data for x is available?
As for the array example, here's what the workspace looks like after a Simulink simulation.
It may be difficult to understand...

Wan Ji on 23 Aug 2021
Find is not at all faster than logical inices.
IF you know how to use logical indices to get elements from matrix. I believe you will like it.
A = [true, false, true, false]; % logical inices
B = [4,3,5,6];
B(A) % this gets the value in B corresponds to true element in A
Then
ans =
4 5
But find should have such a following process
p = find(A);
B(p)
Also,
ans =
4 5
Find sometimes can be implemented by
n = 1:1:length(A);
p = n(A)
Then
p =
1 3
A on 23 Aug 2021
Thank you for your answer, and thank you for writing the program that turns into find.
Also, I apologize for my bad way of asking the question, it is not so clear.
In this case, I think x is the data to be retrieved from the simulator in real time.
In this case, is it still possible to detect x greater than 10 with the program you taught me?

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