Triangular Backsubstitution about cusp-library HOT 4 OPEN

Not to my knowledge.  In general, I don't know of any to implement 
backsubstitution
efficiently with 1000s of threads on a GPU.

However, if find any references that explain how it can be done, I'd be happy 
to look
at them.

The algorithm in Cusparse works reasonably well.

There is version of the triangular solve method by Li and Saad in one of the 
clones.  In my opinion it isn't very robust without additional functionality to 
perform reordering to reduce the number of sequential stages.