Problem with time series analysis function using detrended fluctuation analysis

Hi,

this is quite a specialized question.

I am trying to analyze a time series (standard matrix) using detrended fluctuation analysis. The script/function I am using is dfaedit (see attachment). The problem I am facing is that the results come out negative even though the results are only meant to be positive between 0-2. Hence there must be an issue with the calculation but I can not identify what it is.

Does anyone have an idea?

Answer 1

[Star Strider]

How does this differ from How to loop through cell array and apply script to each double? that you did not follow up on, instead posting this?

load('standard_matrix.mat')
whos('-file','standard_matrix')

  Name                   Size            Bytes  Class     Attributes

  standard_matrix      512x1              4096  double              

The ‘dfaedit’ function still requires as arguments ‘file_name’, ‘plot_flag’, ‘outfile_flag’, and ‘out_command_flag’.

How are you calling it?

What are the data and whatt do you want from them?

.

[lil brain]

Thats true, I did not think those two questions werediscussing the same thing. In How to loop through cell array and apply script to each double? I was wondering why I wasnt able to apply the fucntion to the entire cell in a loop.

But to test if I get the right output I simply tested H = dfaedit(standard_matrix(:,1),0,0,0). But as the output is negative I wondered why this is. And if there is an inherent mistake I am making in this test. The other question is a seperate issue in my opinion.

The data is simply a movement time-series and I am expecting a single result for the result of the analysis.

[Star Strider]

First, it is always best to post the relevant code and data you are working with. Posting a single file and the function without any explanation justt does not provide enough information.

Second, I do not understtand the reason that you are using that function. What problem are you solving? (What are the data? What result do you want from them?)