Setting up CLASS with classy libclass.a

[matthemattix]

My end goal with CLASS is to modify it to test new physics. However, I seem to have an issue getting started. I have downloaded CLASS from github on Mac Sonoma 14.6.1. Have cleaned and compiled with no errors. However, when I go to the python directory and run setup.py to set up classy I get this:

g++ -bundle -undefined dynamic_lookup -arch x86_64 -g build/temp.macosx-10.9-x86_64-3.8/Users/username/class_public-master/python/../python/classy.o -L/Users/username/class_public-master/python/.. -L/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16/lib/darwin -lclass -o build/lib.macosx-10.9-x86_64-3.8/classy.cpython-38-darwin.so
ld: library 'class' not found
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
error: command 'g++' failed with exit status 1

From what I can tell there should be a libclass.a or an libclass.so that is created in the build directory when CLASS compiles. All I have is an empty lib directory in the build directory and no libclass files.

Without this I can't use classy.

Is my approach wrong here? Do I have to alter something?

Thanks,
-Matt

[lesgourg]

Dear Matt, it sounds like you only did 'make class'. This would only compile the C code - but not the library libclass, nor the wrapper classy. Instead, you are supposed to do 'make clean' and then just 'make' (or 'make -j' for a faster compilation). This will compile everything in a row: C code, library, and classy wrapper. You don't need to worry about setup.py ever, this will be run through the 'make' command. (Note: In a few days, we will release class v3.3.0, and there it will be even simpler: you'll just need to do 'make install .')

[matthemattix]

Thanks! That fixed my issue.

-Matt