Chronos: Change TCNForecaster's default parameter num_channels to [16]*3

[devWangBin]

Description

Chronos: Change TCNForecaster's default parameter of num_channels from [30]*7 to [16]*3

1. Why the change?

Based on experimental results on real datasets, we find that the parameter setting of [16]*3 generally have more stable and superior performance.

Github issue link: https://github.com/intel-analytics/BigDL/issues/5606

[TheaperDeng]

I am pretty sure this should work, but we should be careful about this. @liangs6212 do you have any comments about this?

[liangs6212]

I am pretty sure this should work, but we should be careful about this. @liangs6212 do you have any comments about this?

Can the same modification be used for TF2 TCNForecaster?

[TheaperDeng]

I am pretty sure this should work, but we should be careful about this. @liangs6212 do you have any comments about this?

Can the same modification be used for TF2 TCNForecaster?

Yeah, good catch. @devWangBin Please change bigdl.chronos.forecaster.tf.tcnforecaster as well

[devWangBin]

Yeah, good catch. @devWangBin Please change bigdl.chronos.forecaster.tf.tcnforecaster as well

Okay, no problem.

[TheaperDeng]

@plusbang @rnwang04 Since this default value is used everywhere so I am asking more stakeholders to have a review

[rnwang04]

LGTM

[plusbang]

LGTM