Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

non-uniform interpolation function

Please login with a confirmed email address before reporting spam

Hi,
recently, I'm trying to change the material properties(electric conductivity); f(x,y,z,t)
however, i only know make interpolation function t,f(t).
but my data is non-uniform distribution.
how can i do it?
summary, not just for t,f(t) but plus x,y,z

best wishes.

3 Replies Last Post 2017年2月2日 GMT-5 08:50
Jeff Hiller COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 8 years ago 2017年2月1日 GMT-5 11:51
Hello Min,
Interpolation functions are documented in the Reference Manual for COMSOL Multiphysics version 5.2a, see page 277 and following. Interpolation functions support up to 3 arguments, but not 4.
You can access all manuals through File > Help > Documentation.
Best,
Jeff
Hello Min, Interpolation functions are documented in the Reference Manual for COMSOL Multiphysics version 5.2a, see page 277 and following. Interpolation functions support up to 3 arguments, but not 4. You can access all manuals through File > Help > Documentation. Best, Jeff

Please login with a confirmed email address before reporting spam

Posted: 8 years ago 2017年2月2日 GMT-5 01:08
thank you for your help Jeff,
I'm trying to make it with 2-D with time,
However, I got one problem which is
In my data,
x y value(at t0) value(t1) value(t2) and so on
so i used interpolation function in global definition
x y value(t0) = first function(named f1)
x y value(t1) = second function(named f2)
.
.
.

and now I'm trying to make piecewise function with functions(f1,f2,...) as i made above
but it doesn't work saying that it wasn't defined.
Can you tell me what's wrong with it?

summary,
I'm trying to make piecewise function
t0~t1 : f1
t1~t2 : f2

but it doesn't work because f1, f2 weren't defined.

Best wishes.
thank you for your help Jeff, I'm trying to make it with 2-D with time, However, I got one problem which is In my data, x y value(at t0) value(t1) value(t2) and so on so i used interpolation function in global definition x y value(t0) = first function(named f1) x y value(t1) = second function(named f2) . . . and now I'm trying to make piecewise function with functions(f1,f2,...) as i made above but it doesn't work saying that it wasn't defined. Can you tell me what's wrong with it? summary, I'm trying to make piecewise function t0~t1 : f1 t1~t2 : f2 but it doesn't work because f1, f2 weren't defined. Best wishes.

Jeff Hiller COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 8 years ago 2017年2月2日 GMT-5 08:50
I would recommend handling this as a function of 3 arguments, but I suspect I do not understand some fundamental reason you may have for staying away from that simpler approach. For further discussion, I invite you to contact COMSOL's technical support team at www.comsol.com/support/ .
Best,
Jeff
I would recommend handling this as a function of 3 arguments, but I suspect I do not understand some fundamental reason you may have for staying away from that simpler approach. For further discussion, I invite you to contact COMSOL's technical support team at www.comsol.com/support/ . Best, Jeff

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.