Hi Alexander,

To the 2nd item: we had a comparable proposal for the conventional V ops in the past (see https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/23). It seems like this proposal requires still all P entries in all arrays and thus has the \Omega(P) time and space overhead that we're trying to push down to O(k) (while we assume that k=O(log(P)) at very large scale).

All the Best, Torsten -- bash$ :(){ :|:&};: --------------------- http://www.unixer.de/ ----- Torsten Hoefler | Performance Modeling and Simulation Lead Blue Waters Directorate | University of Illinois (UIUC) 1205 W Clark Street | Urbana, IL, 61801 NCSA Building | +01 (217) 244-7736