How do I average a data which runs on a cycle?

I have a data file that goes like -1 0.2 -0.5 0.15 0 0.143 0.5 0.122 1 0.1234 1 0.233 0.5 0.32 0 0.322 -0.5 1.22 -1 1.333 then cycle 2 which has same x values but different y values . the cylce continues for 100 times. i want to have a average of y values for each x values.so finally i have the average y value

Answer 1

[John D'Errico]

You could use my consolidator , found on the file exchange.

It can form the mean y value for each independent x. It could even be used to compute a standard deviation of y within each x.

[DebiPrasad]

Thats a really great function. and it works but I need the data to be cylcic . -1 to 1 and then 1 to -1. the function averages all the duplicities and gives me -1 to 1.

[DebiPrasad]

I should get data from -2 to 2 and then again from 2 to -2. so it gives me a cycle!

[John D'Errico]

Then you need to tell consolidator that there are two types of points. Thus you have an increasing section and a decreasing one. Flag each point with a 1 or -1 that indicates which way the cycle is going. Then use consolidator with the 2 dimensional input to distinguish which elements to average.

Answer 2

[Thorsten]

Read your data into one big 100xN matrix D (e.g., using dlmread) and then use mean(D). Voila.

[DebiPrasad]

Thanks Thorsten. But I dont want the mean of all y values. But y values of each x values. Since its a cycle, i will get 100 x values of values from -1,5 to 1.5, and corresponding y values. the y data should be the y mean of the each y value in the x value.

[Thorsten]

Oh, I see. Is your example one actual line of your file? It does not contain x values -1.5 and 1.5. Are the x values always in the same order -1, -0.5, 0.5, 1, 1, 0.5, -0.5, -1? Then you can construct your Y matrix from the big data matrix D as

Y = [D(:, 2:2:10); D(:, 20:-2:12)];

and compute the mean as

mean(Y)

for values of a = -1:0.5:1;

If you need something else, please provide more information about the file; maybe you should post the file or the first, say, 10 lines.

[DebiPrasad]

I should get data from -2 to 2 and then again from 2 to -2. so it gives me a cycle!

[Thorsten]

But in your example you have only x values that run from -1 to 1 and back from 1 to -1. So what do the real data look like? Could you provide the file?