Array math: The logical indices contain a true value outside of the array bounds.

Question

Rob 2023-4-9

编辑： KALYAN ACHARJYA 2023-4-9

I have 1-dimensional vectors, x and y. To return the x value corresponding to the maximum y value, I can use:

x(y==max(y))

Cool!

Now I need to do this for several 1-dimensional y vectors. I could make a loop. But how could I use an array instead?

Similarly, I was able to use this function to return multiple amplitudes in a array, 1 for each y vector.

amplitude = abs( max(y) - min(y) )/2;

Answer 1

KALYAN ACHARJYA 2023-4-9

编辑：KALYAN ACHARJYA 2023-4-9

The y value can be store in a cell array and use the cellfun to get the result. Here is an example-

#Without Loop

x=[10 12 13 7 0 9];
y={[50 11 9 19 10 49],[30 11 9 19 10 49],[10 11 9 79 10 49]};
dat=cellfun(@(n)x(n==max(n)),y)
dat = 1×3
    10     9     7

#Using loop

n=length(y);
dat=zeros(1,n);
for i=1:n
     dat(i)=x(y{i}==max(y{i}));
end 
dat
dat = 1×3
    10     9     7

Avoiding a loop in all cases is no better decision, instead it can be used loops with proper pre-allocation. Use as per your requirements.