How to calculate moving average

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Mekala balaji
Mekala balaji el 16 de Nov. de 2017
Editada: dpb el 25 de Nov. de 2020
Hi,
I have following data:
0.10
0.24
0.30
0.25
0.33
0.35
0.46
0.47
0.48
0.51
0.52
0.53
0.53
0.57
0.58
0.58
0.58
0.59
0.63
0.64
0.66
0.72
I want to take 3-points moving average,
Please help some one
  2 comentarios
Quin Silk
Quin Silk el 11 de Dic. de 2019
Can someone write code to do it without using movmean?
Star Strider
Star Strider el 11 de Dic. de 2019
@Quin Silk — See the Moving Average Filter link in my Answer.

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Respuestas (6)

Bandar
Bandar el 11 de Dic. de 2019
Take a look this data
file=[1 2 3 4];
movmean(file,3)
which returns
1.5000 2.0000 3.0000 3.5000
The filter works as follows:
1 2 (1+2)/2 = 1.5 when k points at 1
1 2 3 (1+2+3)/3 = 2.0 when k points at 2
2 3 4 (2+3+4)/3 = 3.0 when k points at 3
3 4 (3+4)/2 = 3.5 when k points at 4
Now it is easy to convert it to a logical code or merely use movmean().
  3 comentarios
Bandar
Bandar el 11 de Dic. de 2019
A=[1 2 3 4 5 6];
m=ones(1,length(A));
for i=1:length(A)
if i == 1
m(i) = (A(i)+A(i+1))/2;
elseif i == length(A)
m(i) = (A(i-1)+A(i))/2;
else
m(i) = (A(i-1)+A(i)+A(i+1))/3;
end
end
movmean(A,3)
m
Micheal Omojola
Micheal Omojola el 8 de Sept. de 2020
@Bandar Aldhafeeri: Thank you! Your answer was helpful.

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KL
KL el 16 de Nov. de 2017
If you have 2016b or later, use movmean,
mean_arr = movmean(your_array,3)

Star Strider
Star Strider el 16 de Nov. de 2017
Use the movmean (link) function (introduced in R2016a).
You can also use the filter function. See the section on Moving-Average Filter (link).
  1 comentario
Pallavi Bharati
Pallavi Bharati el 25 de Nov. de 2020
How to do centered moving average ...three point centred moving average in matlab without the movmean command as i have matlab 2015

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dpb
dpb el 16 de Nov. de 2017

Sudhakar Rayabarapu
Sudhakar Rayabarapu el 8 de Sept. de 2018
Editada: Sudhakar Rayabarapu el 8 de Sept. de 2018
Name your data array A; and keep as a column; then use this command
OutPut = tsmovavg(A, 's', 3, 1)
this will give you the simple moving average

Pallavi Bharati
Pallavi Bharati el 24 de Nov. de 2020
Can anyone help me to compute three point moving average of a 5 year data.I used the filter command but the result are erroneous .I am using MATLAB 2015.And I have a huge data 5 year day wise data and i have to compute three point moving average for each month .
  2 comentarios
Pallavi Bharati
Pallavi Bharati el 24 de Nov. de 2020
Using looping can be erroneous for so large data please suggest something else
dpb
dpb el 24 de Nov. de 2020
Editada: dpb el 25 de Nov. de 2020
The results aren't "erroneous" (presuming you defined the coefficients correctly), they just depend on how one treats the end conditions...examine the following:
>> x=1:10;
>> movmean(x,3)
ans =
1.5000 2.0000 3.0000 4.0000 5.0000 6.0000 7.0000 8.0000 9.0000 9.5000
>> filter(ones(1,3)/3,1,x)
ans =
0.3333 1.0000 2.0000 3.0000 4.0000 5.0000 6.0000 7.0000 8.0000 9.0000
>> conv(x,ones(1,3)/3,'same')
ans =
1.0000 2.0000 3.0000 4.0000 5.0000 6.0000 7.0000 8.0000 9.0000 6.3333
>> conv(x,ones(1,3)/3,'valid')
ans =
2.0000 3.0000 4.0000 5.0000 6.0000 7.0000 8.0000 9.0000
>>
movmean special-cases the end positions to change the divisor to match the number of elements from 2:N on each end; filter and conv do not.
It's up to you to determine the solution you wish to use; none is theoretically any more or less correct than any other; just different assumptions are made.

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