Merge faster Riemann R function #67

Job	Run time
linux_gcc (ubuntu-latest, Debug)	4m 59s
linux_gcc_sanitizers	2m 21s
linux_gcc_valgrind	1m 8s
linux_gcc (ubuntu-latest, Release)	2m 6s
linux_clang (ubuntu-latest, Debug)	3m 31s
linux_clang (ubuntu-latest, Release)	1m 56s
macos_clang (macos-latest, Debug)	6h 0m 16s
windows_mingw64 (windows-latest, Debug)	5m 45s
macos_clang (macos-latest, Release)	1m 31s
windows_msvc2022	2m 46s
windows_mingw64 (windows-latest, Release)	3m 21s
	6h 29m 40s

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