How to apply moving harmonic average on an array?

Hi,

I have attached the data Kd_i = (115*1), I want to keep first and last values as it is in the data (or also shown in the figure below) and in the row want compute the harmonic average of first and second values (red square), in the 3rd row I want to compute the harmonic average of second and thrid values (green square) asn so on...

I mean first and last values remain same (just to have final array/vector of equal length), and then from second row it moves the by computing the harmonic mean of first and second row, until second last row. Can someone help me to write it code?

Thanks

Answer 1

[Abhishek Tiwari]

Hi,

A 'For' loop and harmmean() may do the same thing, as shown.

n = numel(Kd_i);
harmonicMean = Kd_i;

for idx = 2:n-1
    harmonicMean(idx) = harmmean(Kd_i(idx-1 : idx, 1));
end

[Nisar Ahmed]

@Abhishek Tiwari In that case, which wil be the new Kd_i? I mean after applying harmonic ave. Is the new array harmonicMean = Kd_i;

[Abhishek Tiwari]

Yeah, harmonicMean has first and last values from Kd_i, and the remaining are the harmonic means of two rows (prev. and current).

[Nisar Ahmed]

thanks

Answer 2

[Star Strider]

If you want to calculate it as described in the harmmean More About section, perhaps something like this would work —

movhm = @(x) 2./movsum(1./x,2);

v = 1:5

v = 1×5

1 2 3 4 5

movhm(v)

ans = 1×5

2.0000 1.3333 2.4000 3.4286 4.4444

would work.

.

Answer 3

[dpb]

Simplest is probably just brute-force --

HM=[Kd_1(1) arrayfun(@(i)harmmean(Kd_1(i:i+1)),1:numel(Kd_1)-1) Kd_1(end)].';

[Nisar Ahmed]

@dpb What is K here; harmmean(K(i:i+1)), is it the same Kd_i? and if I change as K = Kd_i, following error appears

Error using vertcat

Dimensions of arrays being concatenated are not consistent.

Error in Const_Q_Full_Mackbeth (line 90)

Kd_HM = [Kd_i(1); arrayfun(@(i)harmmean(Kd_i(i:i+1)),1:numel(Kd_i)-1);Kd_i(end)];

[dpb]

Yeah, I made a local array of K=Kd_1(1:15) so wasn't too much to look at in command window...then didn't fix -- and arrayfun returns row vector didn't transpose...