non-linear analysis

[Paddy1985]

HI guys,

I've got a question some of you might be able to give an answer to straight away, however I'm struggling with it and it's just causing me a massive headache!

I'm looking into variability of gait as in walking where I'm exploring the use of poincare plots. I've managed to plot them in graphs, fit circles onto it and linear trends. However, I'm struggeling taking doing further stats on it such as calculating the Standard deviations in both diagonal orders (see figure attached).

I'm using LabVIEW 8.5 and the VI written so far including data file is attached.

Could some of you please help me out or give me some guidance in order to:

1) calculate the standard deviation (SD1) from the linear fit

2) calculate the standard deviation (SD2) from the centre of the circle

3) possibly replace the circle with a elipse covering all the points as in best fit?

Many thanks,

Patrick

[altenbach]

You forgot to include one of the subVIs.

(Your code is also hurting my computer, because it grabs all CPU forever while running. Place a small wait inside the loop or, even better, recalculate only of one of the inputs change. There are many other things wrong. For example use "index array" to get a column, not "delete from array". Wrong tool!)) 

You can draw an ellipse using e.g. code as follows (from here) given a complex array forming a unit circle:

Slightly streamlined from Ellipse2.vi (from here)