Don't crash when color cluster size == number of points (#150) #442

Job	Run time
prepare_matrix	5s
Cross platform build (Windows-msvc2019, windows-2019, msvc-2019, 16, MD, Release)	8m 58s
Cross platform build (Linux_gcc11, ubuntu-22.04, gcc, g++, gcc, 11, Release, Linux, libstdc++11)	4m 10s
Cross platform build (Macos_xcode14.3, macos-13, apple-clang, 14, Release, Macos, 14.3, libc++)	4m 53s
	18m 6s

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