Encountered problems while compiling Yade.

Hello everyone,

I am writing to seek help with installing the Yade from source code on Ubuntu 18.04. The source code was downloaded on February 23, 2023. I made modifications to the polyhedra02.cpp file and its corresponding hpp file, and encountered errors during the compilation and installation process following the installation instructions.

Specifically, I encountered the following issues:

After entering the command "sudo add-apt-repository ppa:yade-users/external" and "sudo apt-get update", I received the following error message:
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Error:7 http://ppa.launchpad.net/yade-users/external/ubuntu bionic Release
  404 Not Found [IP: 185.125.190.52 80]
Reading the package list... Done
E: The repository "http://ppa.launchpad.net/yade-users/external/ubuntu bionic Release" does not have a Release file.
N: This source cannot be used securely for updates, so it is disabled by default.
N: See the apt-secure(8) manual for details on repository creation and user configuration.
********************************************************************************************
After installing the external software listed in the Prerequisites, I encountered the following error during the Yade compilation process:
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/home/x/myYade/trunk/pkg/dem/CapillaryPhysDelaunay.cpp: In function ‘boost::python::api::object boost::python::detail::make_function_dispatch(F, const CallPolicies&, const Signature&, mpl_::false_) [with F = boost::python::detail::member<double, yade::ElastMat>; CallPolicies = boost::python::default_call_policies; Signature = boost::mpl::vector3<void, yade::ElastMat&, const double&>]’:
/home/x/myYade/trunk/pkg/dem/CapillaryPhysDelaunay.cpp:34:1: internal compiler error: 段错误
 } // namespace yade
 ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-7/README.Bugs> for instructions.
CMakeFiles/pkg_dem.dir/build.make:121: recipe for target 'CMakeFiles/pkg_dem.dir/pkg/dem/CapillaryPhysDelaunay.cpp.o' failed
make[2]: *** [CMakeFiles/pkg_dem.dir/pkg/dem/CapillaryPhysDelaunay.cpp.o] Error 1
CMakeFiles/Makefile2:356: recipe for target 'CMakeFiles/pkg_dem.dir/all' failed
make[1]: *** [CMakeFiles/pkg_dem.dir/all] Error 2
Makefile:149: recipe for target 'all' failed
make: *** [all] Error 2
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Regarding the above errors, I have two questions:
1) How can I solve the above problems?
2) As the compilation process has partially completed (build folder has generated some files), do I need to delete the generated files (or registry entries created elsewhere) before recompiling?

Thank you for your kind assistance.

xue