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"Update Solution" does not increase the time steps in Results
Posted Jan 4, 2024, 6:55 p.m. EST Studies & Solvers Version 6.1 4 Replies
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Hi Guys,
What I intended to do is 1: First run a short time dependent study to make sure everything works OK in the time dependent study setting. This is already done. And Comsol shall already have a good solution for the whole setup. (This one step took 3h to finish.) 2: Increase the time steps setting in the solver and use the "Update Solution". Now I expect the time dependent study will only need to calculate the value for the increased time steps instead of solving for everything.
But when I tried this, it seems the "Update solution" did nothing. At least in the resuts, the time steps results are still the same as the before.
I am wondering if there is some setting I did wrong in this case, or I misunderstood the functionality of "Update Solution". Could you help me if you encoutered something like this before?
Thank you.
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Hi Duanhui,
Yes, Update Solution is not applicable in this situation. From the COMSOL documentation:
Updating the solution updates the current study (if selected) or all studies if no study is selected. This is useful in the following situations when you have:
- Added or edited variables or parameters and want to use these during postprocessing without having to solve the model again.
- Changed the element order and want to interpolate the solution onto the new elements for results analysis or other purposes.
- Remeshed or modified a geometry and want to interpolate the solution onto the new geometry for results analysis or other purposes.
In all these cases, the COMSOL software passes or interpolates the solution to the resulting datasets but does not recompute it to reflect any changes in variables, equations, mesh, or geometry.
If you make changes to the model that affect the solution, you must recompute the solution; just updating the solution does not take such changes into account.
Best regards,
Magnus
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Hi Duanhui,
Yes, Update Solution is not applicable in this situation. From the COMSOL documentation:
Updating the solution updates the current study (if selected) or all studies if no study is selected. This is useful in the following situations when you have:
- Added or edited variables or parameters and want to use these during postprocessing without having to solve the model again.
- Changed the element order and want to interpolate the solution onto the new elements for results analysis or other purposes.
- Remeshed or modified a geometry and want to interpolate the solution onto the new geometry for results analysis or other purposes.
In all these cases, the COMSOL software passes or interpolates the solution to the resulting datasets but does not recompute it to reflect any changes in variables, equations, mesh, or geometry.
If you make changes to the model that affect the solution, you must recompute the solution; just updating the solution does not take such changes into account.
Best regards,
Magnus
Thank you Magnus. You cleared my confusion. May I ask if I want to take advantages on the solution from step 1 to get results of the increased time steps, what will be the right approach? My goal is to save the time for comsol to get an initial solution, which seems to take the most of the time. Is there a blog or reference I can learn from? Thank you!
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Dear Duanhui,
You should create a new study and set the initial values of the variables to be solved to the solutions you have already obtained (this option is located in the "Values of Dependent Variables " section of the study).
Best,
Jake
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Dear Duanhui,
You should create a new study and set the initial values of the variables to be solved to the solutions you have already obtained (this option is located in the "Values of Dependent Variables " section of the study).
Best,
Jake
Got it. That makes sense. Thank you Jake!