Improve Squirrel's Rsqrt and refactoring Logisitic #669
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- Change degree-4 polynomial to degree-3 polynomial for the 1/(1+exp(-x)) approximation - A customized Rsqrt to support a large input, i.e., rsqrt(x) for x > 2^fxp
fionser
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Pull Request
What problem does this PR solve?
Change degree-4 polynomial to degree-3 polynomial for the 1/(1+exp(-x)) approximation.
The degree-3 polynomial seems enough.
A customized Rsqrt to support a large input, i.e., rsqrt(x) for x > 2^fxp
We need the Rsqrt to accept a very large value for XGBT. However the current SPU's implementation can
work properly only when |x| < 2^fxp where the fxp is the fixed-point precision.
Issue Number: Fixed #
Possible side effects?
Performance:
Backward compatibility: