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interpolation functions

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Hi,
As a new COMSOL user, I am currently trying to run a simulation of an Ar plasma. To switch easily between some different conditions I wanted for, I defined some interpolation functions from tables .txt. The functions plot correctly, showing a very OK-looking curve representing the rate coefficient in function of the electron energy. However, I want to plug them in the Reaction parameters sections, in the collision reaction settings, instead of the lookup tables of the rate coefficients. But it sends an error message :

Unknown variable name.
- Table row: 1
- Table column: 2
- Function name: ksig_11_1
Error in multiphysics compilation.

Can you help me ? I defined a variable for the energy, so I don't think it's the problem.

Thanks

Kevin

2 Replies Last Post Jun 9, 2017, 5:33 a.m. EDT
Jeff Hiller COMSOL Employee

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Posted: 7 years ago Jun 8, 2017, 10:07 a.m. EDT
Updated: 7 years ago Jun 8, 2017, 11:06 a.m. EDT
Hello Kevin,
My guess is that you forgot to pass an argument to your function.
To call the function ksig_11_1 with the argument T, the syntax is
ksig_11_1(T)
and if there are several arguments to pass, you separate them with commas, like this ksig_11_1(arg1,arg2,arg3).
If you don't pass the argument(s) between parentheses, COMSOL concludes that you must be talking about a variable called ksig_11_1, not the function called ksig_11_1, and you get an error message like the one you got.
If I misunderstood, please post your mph file.
Best,
Jeff
Hello Kevin, My guess is that you forgot to pass an argument to your function. To call the function ksig_11_1 with the argument T, the syntax is ksig_11_1(T) and if there are several arguments to pass, you separate them with commas, like this ksig_11_1(arg1,arg2,arg3). If you don't pass the argument(s) between parentheses, COMSOL concludes that you must be talking about a variable called ksig_11_1, not the function called ksig_11_1, and you get an error message like the one you got. If I misunderstood, please post your mph file. Best, Jeff

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Posted: 7 years ago Jun 9, 2017, 5:33 a.m. EDT
Hello,
Thanks for your quick reply. The problem is, I never defined any function called ksig_11_1. It seems to be a function of COMSOL itself, related to the concerned reaction node (in which I tried to call the interpolation function HKelMB), where the number _11_ appears to refeer to the intern name of the reaction node I created (e+H=>e+H), but using the order of creation instead of the name I gave to it.

Moreover, I had called my function with my variable name (defined in the global variable node Variable1) wrote into parenthesis for the argument, as you said, so I don't think this is the location of the problem. May my variable be actually badly defined ? Or do I call my function in the wrong way ?


I would post my mph file, but there is an error message keeping telling "file extension error".

Thanks in advance,

Kevin
Hello, Thanks for your quick reply. The problem is, I never defined any function called ksig_11_1. It seems to be a function of COMSOL itself, related to the concerned reaction node (in which I tried to call the interpolation function HKelMB), where the number _11_ appears to refeer to the intern name of the reaction node I created (e+H=>e+H), but using the order of creation instead of the name I gave to it. Moreover, I had called my function with my variable name (defined in the global variable node Variable1) wrote into parenthesis for the argument, as you said, so I don't think this is the location of the problem. May my variable be actually badly defined ? Or do I call my function in the wrong way ? I would post my mph file, but there is an error message keeping telling "file extension error". Thanks in advance, Kevin

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