Merge faster Riemann R function #83

Job	Run time
linux_clang (ubuntu-latest, Debug)	3m 25s
linux_gcc (ubuntu-latest, Debug)	4m 24s
linux_clang (ubuntu-latest, Release)	1m 13s
linux_gcc_sanitizers	2m 36s
linux_gcc (ubuntu-latest, Release)	2m 5s
linux_gcc_valgrind	1m 39s
macos_clang (macos-latest, Debug)	2m 51s
macos_clang (macos-latest, Release)	1m 37s
windows_mingw64 (windows-latest, Debug)	5m 26s
windows_msvc2022	1m 6s
windows_mingw64 (windows-latest, Release)	3m 1s
	29m 23s

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