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Set boost options in CMakeLists.txt to not promote doubles to long doubles. Promotion
incurs performance penalty on all platforms, and particularly aarch64.
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Closing as part of a housekeeping pass — with thanks; this was a real find (silent long-double promotion in Boost.Math is exactly the kind of thing nobody suspects until they profile), and the one-line policy define was the right minimal fix. The reason for closing rather than merging: the repository's mainline is now the ground-up Rust implementation, which carries neither Boost nor the CMake build this patches, so there is no target for the change. The C++ 1.x line is frozen; anyone building it from source via the v1.10.x tags can apply |
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Fixes #966
This fix resolves performance issue where Boost::math unnecessarily promotes doubles to long double, which is not fully supported by hardware leading to slow-downs.
The change is to set a define during cmake process which prevents promotion ( -DBOOST_MATH_PROMOTE_DOUBLE_POLICY=false )