How to ensure two vectors are the same size when using findpeaks?

I am using findpeaks to determine the local minima and maxima in a given input signal. I am then calculating the peak-to-peak difference between each of these minima/maxima pairs throughout the entire signal. Shown is my current code:

signal = myvector;

[pksmax,locsmax] = findpeaks(signal);
[pksmin,locsmin] = findpeaks(-signal);
 
realpksmin = -1*pksmin;

for j = 1:size(realpksmin)
    pk2pkmaxmin(j) = abs(pksmax(j) - realpksmin(j));
end 

Most of the time,

size(pksmax) == size(pksmin)

Sometimes these two vectors differ in size very slightly. If the above statement is false, then I have an error in my loop,

Index exceeds the number of array elements (154).

How can I ensure that

size(pksmax) == size(pksmin)

is always true upon using findpeaks(signal)?

Answer 1

[Utkarsh Belwal]

The number of local maxima and minima need not be same for every signal so you can’t get size of both the arrays same every time. A possible solution is to use array slicing and reduce the size of the large array to smaller one. Refer to the code below,

commonLength = min(length(pksmax) , length(pksmin));
pksmax_new = pksmax(1:commonLength);
pksmin_new = pksmin(1:commonLength);

Alternatively you can also insert zeros to the shorter array so that it’s length becomes equal to the longer one.