Temperature difference between two steps does not decrease with reducing step interval about underworld2 HOT 16 OPEN

re-invited @julesghub

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Hi Ting, I think the following line is the problem
if its == dT_maxIts - 1:

It will only fire when its == 4, which is what your output shows.

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Thanks, Julian.
You are right, this coding mistake occurred when I tried to simplify the original script.
However, this 'temperature difference does not decrease with reducing step interval' issue persists even when this coding mistake is corrected. See screenshots below.

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The three columns of max_dT_Array in the standard output are iteration (its), dt, and dT_max, respectively.

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In the code every iteration is using a different initial temperature and temperatureDot. This isn't what you want right?

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I thought it is the same initial temperature and temperatureDot. Since I used
temperatureField.data[:] = T_old.data[:]
temperatureDotField.data[:] = Tdot_old.data[:]

to reset the temperature after each iteration.

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oh I see. Why don't you create fields temperature0 and temperatureDot0 for the initial conditions. Just to ensure you don't have to write over the numpy arrays.

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How do I create and temperatureDot0 for the initial conditions?

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The initial values of temperatureDot0 should always be zero. So I suggest
using temperatureDot0.data[:] = 0 in the loop.

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temperature reset in the while loop is changed as below:
temperatureField.data[:] = T_old.data[:]
temperatureDotField.data[:] = 0.0 #Tdot_old.data[:]

The temperature difference is as below, it does not show any dependence on dt.

At an earlier step, the temperature difference does reduce with reducing dt.

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Instead of doing
T_old = temperatureField.copy()
Can you make T_old a new mesh variable, i.e.
T_old = mesh.add_variable(....)

I think the copy() is not a 'deep' copy and is potentially causing the issue.

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creating a new mesh variable for T_old does not make any difference. Values of the derived dT_max are exactly the same as before.

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Can you upload a version of the model file and I can look at it more closely. The easiest way would be to make a private github repo and invite me to it. Remember to let me know the version of the code you're using.

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OK, I will do that.

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Hi Julian, I have invited you to my temporal repository. The swarm file exceeds the 25 Mb limit, so I shared it using my net-disk. You can download it through the link in README.md. Thanks!

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@tingyang2004 Could you re-invite me to the repo - unfortunately the invitation expired. opps

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