+bool
+Beaming_pattern::is_next_to_invisible_stem (vsize i) const
+{
+ return infos_[i].invisible_
+ || (i > 0 && infos_[i-1].invisible_);
+}
+
+/*
+ Finds the best point at which to subdivide a beam. In order of priority
+ (highest to lowest) this is
+ - before or after an invisible beam
+ - at the start of a beat group
+ - at the start of a beat
+ - whose position in its beat has the smallest denominator (that is,
+ a stem that starts halfway through a beat will be preferred over stems
+ that start 1/3 or 2/3s of the way through the beat).
+ - any other beam
+ - at the start of a beat group
+ - at the start of a beat
+ - whose position in its beat has the smallest denominator
+
+ If the split point occurs at the start of a beat group or at the start of a
+ beat, at_boundary will be set to true. Otherwise, it will be set to false.
+*/