[legacy] move communication and nn to legacy and refactor logger (#4671)

* [legacy] move communication to legacy (#4640)

* [legacy] refactor logger and clean up legacy codes (#4654)

* [legacy] make logger independent to gpc

* [legacy] make optim independent to registry

* [legacy] move test engine to legacy

* [legacy] move nn to legacy (#4656)

* [legacy] move nn to legacy

* [checkpointio] fix save hf config

* [test] remove useledd rpc pp test

* [legacy] fix nn init

* [example] skip tutorial hybriad parallel example

* [devops] test doc check

* [devops] test doc check

colossalai/nn/layer/utils.py

@@ -0,0 +1,14 @@
+def divide(numerator, denominator):
+    """Only allow exact division.
+
+    Args:
+        numerator (int): Numerator of the division.
+        denominator (int): Denominator of the division.
+
+    Returns:
+        int: the result of exact division.
+    """
+    assert denominator != 0, 'denominator can not be zero'
+    assert numerator % denominator == 0, \
+        '{} is not divisible by {}'.format(numerator, denominator)
+    return numerator // denominator