vanderpol.ode
):x = x_0 y = dx_0 d_x = y d_y = mu * (1 - x**2) * y - x
Note the blank line between the initial conditions and the expression for the derivatives. This is the representation of the form using y
as the derivative of x
. The integration variable in QSoas is the time t
. You can learn more about how to specify differential equations in QSoas from the manual. The game is now simply to use fit-ode to launch the fit interface, but before that, one needs data to serve as a template, generated using generate-buffer:
QSoas> generate-buffer 0 100 1 QSoas> fit-ode vanderpol.ode
Now, the fit interface looks like this:
You can play around with the parameters, and in particular the value of mu
... For every modification, hit the Update button, or just Ctrl+U, to see the effect. For data you'd wish to take a closer look at, use the Push current to stack action from the Data... menu, which creates new buffers on the stack. A nice thing is that QSoas keeps the fit parameters as meta-data, which you can see later on using show:
mu
in the terminal above ?This feature of QSoas makes it easy to quickly explore the effect of the parameters of a model on the shape of the resulting curve. I have used that very heavily in my research, I hope others will find it useful too. Enjoy !
1 comment:
Thhis was lovely to read
Post a Comment