update table caption

Author: zingale

astronum_2019_Castro/astronum-castro-2019.tex

@@ -282,8 +282,8 @@ \section{Modeling Reactive Flow}
 \caption{\label{table:convergence} Convergence of carbon mass density
   ($\rho X(\isotm{C}{12})$) and oxygen mass density ($\rho
   X(\isotm{O}{16})$) for the Strang-CTU algorithm and 2nd and 4th
-  order SDC.  Here $\epsilon_{64\rightarrow 128}$ is the norm of the 
-  difference between a $64^2$ and $128^2$ simulation, and similar for the other $\epsilon$s.  Data taken from \cite{castro:sdc}.}
+  order SDC for a simple reacting acoustic pulse.  Here $\epsilon_{64\rightarrow 128}$ is the norm of the 
+  difference between a $64^2$ and $128^2$ simulation, and similar for the other $\epsilon$s.  The convergence rate is the $\log_2$ of the ratio of errors between different resolutions.  Data taken from \cite{castro:sdc}.}
 \end{table}
 
 \section{Performance Portability}