# How to compute harmonic average on the blocks of an array?

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Nisar Ahmed on 17 Aug 2022
Commented: Nisar Ahmed on 18 Aug 2022
Hi,
I have attached the data Mmin, I want to compute the harmonic average of first 4 values and then next 4 and so on. In short in the blocky form and each block is of 4 values.
Just like shown in the attached figure. after taking harmonic mean of first four values, there will be one value instead of four and so on.
Can someone help me to write it code?
Thanks

David Hill on 17 Aug 2022
a=randi(100,1,100);%some vector
for k=1:length(a)-3
A(k)=harmmean(a(k:k+3));
end
David Hill on 18 Aug 2022
Edited: David Hill on 18 Aug 2022
I misunderstood you. I thought you wanted a rolling harmonic mean 1-4 then 2-5, then 3-6, 4-7, etc. I simple change will correct.
a=randi(100,1,32);%some vector
c=1;
for k=1:4:length(a)-3
A(c)=harmmean(a(k:k+3));
c=c+1;
end
A
A = 1×8
7.1646 42.5475 57.0370 11.6593 49.3414 59.0867 62.9062 33.5323
Or
A=4./m(1:4:end)
A = 1×8
7.1646 42.5475 57.0370 11.6593 49.3414 59.0867 62.9062 33.5323
Nisar Ahmed on 18 Aug 2022
@David Hill thanks, One more thing is if I want to compute moving harmonic mean (like 1-4 then 2-5, then 3-6, 4-7, etc. ) as you did in your previous comment and want to keep the length of array same as before applying moving harmonic mean. How I can do it? e.g.
a=randi(100,1,100);%some vector
for k=1:length(a)-3
A(k)=harmmean(a(k:k+3));
end
length(A) should be equal to length(A)