Recent content by johnpjust

Thanks for your response. I've tried the obvious stuff already (including a sweep over n powers). While I agree with your implicit point (that one does not want to over-fit the data) in trying to generalize the fit, I'm at the point where I need to "step up" to another level of complexity...

Warning...this requires scripting and iteration, and is not theoretical -- it is a real problem I haven't been able to solve, but I'm sure someone here can... :-) Data: each .csv file is a test recorded at a time interval of 7.5Hz and each file has 3 columns. The first column is time in...

Hi lavinia - can you please elaborate for me regarding your response? Thank you!

Thank you for the response. A is indeed an nxn matrix, but we cannot assume n different eigenvalues. Also, f(A) is more like a polynomial function or power series, and so cannot be assumed to be a matrix transformation equation. I incorrectly used the word "scales" in the question title...

Statement: I can prove that if I apply a function to my matrix (lets call it) "A"...whatever that function does on A, it will do the same thing to the eigenvalues (I can prove this with a similarity transformation I think), so long as the function is basically a linear combination of the powers...

Homework Statement find the state transition matrix of a time varying system where: dX/dt = A*X with A = [-1 , exp(-t - (t^2)/2) ; ; 0 , t] (Matlab format - sorry but its easier) Homework Equations How to go about solving such problems in a systematic way? The Attempt at a Solution...

Cool. Well done, and thank you.

For the low values of 'x', the fit curve you've given APPEARS to generally be "under" the data points. Is there a way to manipulate the curve to better fit the data points for low low values of 'x'?

Very impressive! You must do this often to be able to "eye" a fit?! Can you explain a little more (maybe in a different way) on what you've done here? I don't quite understand "y*x as function of x". This is a model to describe relative changes in bulk density of a material, so no physical...

I'm doing research and I have some data (attached -- 'y' = first column, 'x' = second column in CSV format) that I need to find a general curve fit for (function = f(x)/x). This will help me do future predictions. Here are my stipulations: The fit curve must have the format of f(x)/x. Two...

Edit: I think you are right after thinking more about this...since I do have a linear system here...

Hi, yes, I am minimizing the error. But the problem is that I will have many, many equations with only two variables. I am almost certain that this will require some kind of iterative solution. I don't think it has a closed form solution, does it? edit - ok i understand your last question...

Hi guys, I'm a bit rusty on optimization, but i remember enough to be able to setup some problems that I am facing in my research, and would like to know how to go about solving such problems in general. The equations below may have more variables and be in slightly different forms at times...

Folks - doing some research and just needed a reality check on acceleration - let me know if this makes sense: If I drop an object, it should take roughly 5 cm (.102 sec) to reach 1 m/s, correct? I'm using the classical physics equations for this (please do a quick verification on this)...

I appreciate your response, but I'm not going to lie...i can't really follow it. What is the significance that it is a linear operator? I assume that the uniqueness theorem only proves true in a finite domain? Which is fine...but just curious because in electromagnetics we apply it to...