clearer wording on why we built our own task-based library.

theory/paper_pasc/pasc_paper.tex

@@ -342,13 +342,14 @@ SMP~Superscalar \cite{ref:SMPSuperscalar}, OpenMP~3.0 \cite{ref:Duran2009},
 Intel's TBB \cite{ref:Reinders2007}, and, to some extent,
 Charm++ \cite{ref:Kale1993}.
 
-For convenience, and to make experimenting with different scheduling
-techniques easier, we chose to implement our own task scheduler
+Since none of these existing taks-based libraries provide the flexibility
+required to make experiment with different scheduling and communication
+techniques, we chose to implement our own task scheduler
 in \swift, which has since been back-ported as the general-purpose
 \qs task scheduler \cite{gonnet2013quicksched}.
 This also allowed us to extend the scheduler with the concept of
 task conflicts and integrate the asynchronous communication
-scheme described below.
+scheme described further on.
 
 Despite its advantages, and the variety of implementations,
 task-based parallelism is rarely used in