Charm++ parallel programming system

[Gengbin Zheng <gzheng AT illinois.edu>]

There is a recent change in charm git that may affect people using
charm++ load balancing (e.g. NAMD).
In an effort to reduce the size of load balancing database, we changed
the default type for time measurement (i.e. cpu load) from double to
float (by default).

To override the default float type, for example to use double as
before, at build time, use option:   --with-lbtime-type=type
for example,

./build charm++ net-linux-x86_64 --with-lbtime-type=double

charm internally defines (typedef) a type for the time:    LBRealType
To be consistent, it is recommended that you use this type instead of
directly using float/double if one is writing a load balancer (e.g. in
NAMD).

please let us know if you have any question/concern on this change.

Gengbin