it is consitent with the program provided by Oxford Univ
Interest readers can visit that page
and download a complied DFA program that runs much faster.
In stochastic processes, chaos theory and time series analysis, detrended fluctuation analysis (DFA) is a method for determining the statistical self-affinity of a signal. It is useful for analysing time series that appear to be long-memory processes.
Reference: Peng C-K, Havlin S, Stanley HE, Goldberger AL. Quantification of scaling exponents and crossover phenomena in nonstationary heartbeat time series. Chaos 1995;5:82-87.
Hello, can someone please tell me what values i have to use for win lenght, and order? Thank you!
How can I implement two dimensional DFA using this code. Thank you
How can one obtain the distribution of the scaling exponent obtained from DFA? How to obtain the standard deviation (that I have seen in many papers employing DFA) of the estimate?
Thank your for the program.
Can you please tell me what is the Alpha value for the DATA1 that exists in the download submission?
do you have the MF_DFA code?
i have a signal of 700 points,what necessary changes should i make in the program..pls reply soon..
Please let me know if I can have the input as row vector? I am having time series of different length and when I run, I am getting values more than 1.Do I need to change the value of n accordingly?
Dear Guan Weye;
There is sample frequency that works better with DFA?
Dear Guan Wenye;
Thanks for you answer. I do have time series of diferent lengths. However, I find cross-overs. I am not sure whether I should take just one cross-over, the one that has the best fit for all the experiments. In other words, I am taking just boxes size up to 200ms. thanks Erika
To Erika Rodriguez :
you can use time series of different lengths if the length is long enough to have statistical value.
I should use the same size of n (n<=10,000) if I am comparing the DFA values in different types of lesions in spinal cord.
Dear Guan, the function output "function output1 = DFA (DATA, win_length, order)" with which data have to enter: DATE, win_length, order??
The file dfm.m seems to be truncated at 26 lines leaving the for-loop unfinished.
hi meysam abed
it is consitent with the program provided by oxford univ
i have checked with it
dear Guan have you checked your DFA code with the code in Physionet.org and it's sample data with results???
to mehak gandhi :it would definitely runs faster if you code it in C or Fortran
is the program supposed to run slow
For fewer points, you may get incorrect result :).
this may be a stupid question...but why do you need a minimum of 2000 data points?
add some description