consider refining dispatch to retain variable references longer

[GoogleCodeExporter]

We sometimes implement specific versions of an algorithm with more general
versions of the algorithm.  For example, we can implement
   find(Iterator first, Iterator last, T& value)
with 
   find_if(Iterator first, Iterator last, Predicate pred)
by defining a Predicate that does the comparison.

An unintended side effect of this scheme is that the Predicate must hold a
copy of 'value' and not a reference, because it might be copied to the
device.  A more correct implementation would retain a distinct find() path
through the host/device dispatch and only implement find with find_if in
the device backend.

Like issue #119 this is a case of where Thrust is a little too presumptuous.

Original issue reported on code.google.com by wnbell on 7 Apr 2010 at 11:08

[GoogleCodeExporter]

If we really cared, we could give the predicate to find_if a reference instead 
of a value

Original comment by jaredhoberock on 7 Apr 2010 at 3:01

[GoogleCodeExporter]

The new dispatch layer eliminates this problem.

Original comment by wnbell on 2 Nov 2011 at 4:48

• Changed state: WontFix