alphashapes2d can handle degenerate inputs (thanks to Taras Galkovskyi for the bug report and the fix)
#include <utilities/log.h>
#ifdef LOGGING
static rlog::RLogChannel* rlFiltration = DEF_CHANNEL("topology/filtration/info", rlog::Log_Debug);
static rlog::RLogChannel* rlFiltrationDebug = DEF_CHANNEL("topology/filtration/debug", rlog::Log_Debug);
#endif // LOGGING