View Full Version : freeware entropy calculations

David R Collins
04-09-2002, 01:15 AM
Dear colleagues,

I could use some help finding programs or code to perform entropy
(information) calculations on gait data, along with any
recommendations for which of the many particular versions of entropy
is best suited for movement data. Ready-made freeware programs for
Windows or Dos, or code in C/C++ or Matlab would be ideal, but I
could adapt Pascal or Fortran code fairly readily if the algorithms
are straightforward. (There are many sophisticated programs with time
series methods, but at $400 to $1000+ they are not cheap, nor as
flexible as Matlab. Also, I would like to know at least conceptually
just how things are being calculated, without undocumented
proprietary tricks.)

The goal of the entropy measure is to determine whether patients with
cerebral palsy exhibit more or less complex dynamics before and after
a surgical intervention, and how the pre/post data compares to
able-bodied data. The data is from rather irregular gait, so no
direct time series comparisons are obvious, and there is no standard
against which to calculate standard deviations. I have gotten
together a fair literature search and stack of articles, and have
been busy catching up on the variety of entropy (/information/
complexity/ predictability) measures from nonlinear dynamics, physics
and information theory. A measure that is related to phase space
reconstruction would be great so that I can examine dimensionality

The only freeware program that calculates entropy that I am aware of
so far is the Recurrence Quantification Analysis software from Webber
and Zbilut:
The Biomch-L archives only include references to conferences, e.g.

Thank you for you help!

David R. Collins, Ph.D.
Human Performance Laboratory: Barnes-Jewish Hospital
4555 Forest Park Parkway, St. Louis, MO 63108
314-286-1586 (office)
314-286-1568 (fax)

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