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How do I plot/evaluate a function at specific time point?
Posted Oct 19, 2011, 10:23 a.m. EDT 3 Replies
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Hi all,
I' ve following Question. When I define under Global->Function->Interpolation an function (for example test(t) ), is there a possibilty to plot/evaluate this function for postprocessing only at specific time points. I need the value of test(t) only at the time points t=20s, 30s, 40s... and so on.
Thanks for any help.
Johannes
I' ve following Question. When I define under Global->Function->Interpolation an function (for example test(t) ), is there a possibilty to plot/evaluate this function for postprocessing only at specific time points. I need the value of test(t) only at the time points t=20s, 30s, 40s... and so on.
Thanks for any help.
Johannes
3 Replies Last Post Oct 19, 2011, 1:14 p.m. EDT
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Posted:
1 decade ago
Hi
first remark, be careful with the naming, test() is normally an internally defined COMSOL operator (used in the weak expressions) so pls choose another name to be sure there is no collision there
But then I do not understand your question, you can select in the plot node all items for a time series, or only a few or interpolated ones, see the doc on the higher level plot node
--
Good luck
Ivar
first remark, be careful with the naming, test() is normally an internally defined COMSOL operator (used in the weak expressions) so pls choose another name to be sure there is no collision there
But then I do not understand your question, you can select in the plot node all items for a time series, or only a few or interpolated ones, see the doc on the higher level plot node
--
Good luck
Ivar
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Posted:
1 decade ago
Hi
thanks for the hint with the naming.
My question concerns the following problem. I want to know the residual between a defined interpolation function, e.g. experiment() as interpolation of some measured data from a diffusion experiment and the results of the simulation, but i want the the residuals only at the experimental time points. It's the residual between the experimental and simulated diffusive flux, so I thougt of something like (experiment(t=20,30,40)-(-D*ux(t=20,30,40)))^2
--
Johannes
thanks for the hint with the naming.
My question concerns the following problem. I want to know the residual between a defined interpolation function, e.g. experiment() as interpolation of some measured data from a diffusion experiment and the results of the simulation, but i want the the residuals only at the experimental time points. It's the residual between the experimental and simulated diffusive flux, so I thougt of something like (experiment(t=20,30,40)-(-D*ux(t=20,30,40)))^2
--
Johannes
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Posted:
1 decade ago
Hi
not sure what to propose, that needs some thinking ;)
By defaut, if you are driving your simulation by the difference of the experimantal to the calulcated points, it would take the residual of the interpolated values, at least that is how I understand COMSOL's default behaviour
--
Good luck
Ivar
not sure what to propose, that needs some thinking ;)
By defaut, if you are driving your simulation by the difference of the experimantal to the calulcated points, it would take the residual of the interpolated values, at least that is how I understand COMSOL's default behaviour
--
Good luck
Ivar