What are the differences for x86 vs x64?

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1

I see the error log; "Machine Learning is not available for [linux-x86]".

I wonder the differences between running in x86 and running in x64?

2

Machine Learning does require a 64-bit operating system. This is recommended for the rest of the stack too.

3

Thanks for your reply.
I additionally wonder that what's mean your word;"the rest of the stack".
Also, besides Machine Learning, IS all the other functions running well on x86?