Mixing tee ROM failed #237

Hello There!

I've read tutorial 1 and 2, and try to apply the same ROM workflow on my own tests of cold and hot flow in mixing tee.
The space lists below:

and there are four paramters:

• velocity of inlet1
• temperature of inlet1
• velocity of inlet2
• temperature of inlet2

The outputs are velocity of x, velocity of y, and pressure. I generated 300 snapshots by uniform sampling and splitted 200 snapshots for trainning, 50 for validation, and 50 for testing.

print(train_mus.shape)
print(test_mus.shape)
print(train_snapshots.shape)
print(test_snapshots.shape)

>(200, 4)
>(50, 4)
>(200, 1466)
>(50, 1466)

rom = ROM(db, POD(), RBF())
rom.fit();

errors = rom.kfold_cv_error(n_splits = 10)
print('Average error for each fold:')
for e in errors:
print('  ',e)
print('\nAverage error = {}'.format(errors.mean()))

Finally, the average error is 0.8
I don't figure out what's wrong with my experience. Could you please give me some hits on how to make it work? Thanks a lot!