Matt Borland

@jzmaddock I don't know if it matters but these are the policies being used in the build: ``` cpp_args = [ '-DBOOST_MATH_DOMAIN_ERROR_POLICY=ignore_error', '-DBOOST_MATH_EVALUATION_ERROR_POLICY=user_error', '-DBOOST_MATH_OVERFLOW_ERROR_POLICY=user_error' '-DBOOST_MATH_OVERFLOW_ERROR_POLICY=user_error', '-DBOOST_MATH_PROMOTE_DOUBLE_POLICY=false' ] ``` On M1...

> OK, is it a release build as well? [Here ](https://github.com/scipy/scipy/blob/main/meson.build)is the file with all the compiler flags. I don't see anything specifying debug or release builds. I am likely...

> Hmm, still passing, what's the clang version? We have "Clang version 14.0.0 (clang-1400.0.29.202)" C++ compiler for the host machine: c++ (clang 13.1.6 "Apple clang version 13.1.6 (clang-1316.0.21.2.3)")

> I can't reproduce on your branch with M1 using clang 14 and GCC-12 with C++14,17,20,and 2b. I also had a slightly modified version [here](https://github.com/boostorg/math/pull/936/files) that runs cleanly.

@mckib2 can you try running [this then](https://github.com/boostorg/math/pull/936/files)? Correct me if I am wrong but it should be a direct translation of the minimal python reproducer.

> Some questions: > > * What is the impact on compile time of using concepts rather than SFINAE or nothing at all? Concepts [decrease compile times](https://thecppdev.com/2022/05/21/concepts-vs-sfinae-compilation-time-comparison/?noamp=available) when replacing SFINAE...

Here's a small comparison of the impacts running `../../../b2 test_beta toolset=clang cxxstd=11,14,17,20` using current develop: `60.35s user 6.04s system 543% cpu 12.204 total` with concepts: `60.41s user 6.56s system 544%...

@jzmaddock and @NAThompson I think this is good for review and comments. ccmath/abs, beta, and univariate statistics have been converted to use concepts. As usual Apple's Clang needed some help,...

@jzmaddock I would concur that we probably only need to implement concepts in the user facing functions and not in the detail namespace unless it will save us compile time...

@jzmaddock How do you want to proceed on this one? I grabbed the changes to log1p off your branch, and CI is green with all of the changes so far....