Be compatible with JAX_ENABLE_X64=1

[dachengx]

The current code does not support export JAX_ENABLE_X64=1 which is a pity.

I can understand that these codes:

INT = np.int32
FLOAT = np.float32

are for memory saving, but we still should be compatible with the usage of 64 bits.

[coveralls]

Pull Request Test Coverage Report for Build 7694156133

• 3 of 6 (50.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.06%) to 84.009%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
appletree/plugin.py	0	1	0.0%
appletree/randgen.py	3	5	60.0%

Totals
Change from base Build 7510500909:	-0.06%
Covered Lines:	1970
Relevant Lines:	2345

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💛 - Coveralls