[tmva][sofie] Enhance Softplus stability in ROperator_BasicUnary#21092
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AdityaDRathore wants to merge 1 commit intoroot-project:masterfrom
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[tmva][sofie] Enhance Softplus stability in ROperator_BasicUnary#21092AdityaDRathore wants to merge 1 commit intoroot-project:masterfrom
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sanjibansg
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Hi @AdityaDRathore,
Thanks for this PR. Can you add the tests following the convention we have in the SOFIE sub-directory?
https://github.com/root-project/root/tree/master/tmva/sofie/test
This commit specializes the `UnaryOpTraits` for `kSoftplus` within `ROperator_BasicUnary` to address numerical instability issues (Issue root-project#21071). Changes: - Implemented exact hexfloat thresholding (0x1.4p+4f) to prevent overflow for inputs > 20.0. - Replaced `std::log(std::exp(x)+1)` with `std::log1p(std::exp(x))` to preserve precision for negative inputs. - Validated via dedicated `TestSofieSoftplus` suite unit testing overflow and bit-exact generation. Fixes root-project#21071
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Hi @sanjibansg, thanks for the review I've added tests following the convention in the Sofie test directory, as you mentioned. |
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Description
This PR implements numerical stability improvements for the
Softplusoperator, addressing overflow issues identified in Issue #21071.It supersedes PR #21023 (which was closed due to branch history alignment).
Changes
0x1.4p+4f(20.0f) to preventexp()overflow for large inputs.log(exp(x)+1)withstd::log1p(std::exp(x))to preserve precision for negative inputs.TestSofieSoftplus.cxxverifying bit-exact hexfloat emission and overflow protection.Technical Context
ROperator_BasicUnary(viaUnaryOpTraitsspecialization).Fixes #21071
cc: @sanjibansg @lmoneta @bellenot