+preconditioners.
+
+In Figure~\ref{fig:01}, the number of iterations per second corresponding to
+Table~\ref{tab:01} is displayed. It should be noticed that for TSIRM, only the
+iterations of the Krylov solver are taken into account. Iterations of CGLS or
+LSQR are not recorded but they are time-consuming. It can be noticed that the
+number of iterations per second of FMGRES is constant whereas it decrease with
+TSIRM with both preconditioner. This can be explained by the fact that when the
+number of core increases the time for the minimization step also increases but
+it is also more efficient to reduce the number of iterations.