[SolverAbort] Exception to be thrown by solvers when they cannot continue.

dune/istl/istlexception.hh

@@ -33,6 +33,13 @@ namespace Dune {
     : public BCRSMatrixError
   {};
 
+  //! Thrown when a solver aborts due to some problem.
+  /**
+   * Problems that may cause the solver to abort include a NaN detected during
+   * the convergence check (which may be caused by invalid input data).
+   */
+  class SolverAbort : public ISTLError {};
+
   /** @} end documentation */
 
 } // end namespace

dune/istl/solver.hh

@@ -95,6 +95,9 @@ namespace Dune
         \param x The left hand side to store the result in.
         \param b The right hand side
         \param res Object to store the statistics about applying the operator.
+
+        \throw SolverAbort When the solver detects a problem and cannot
+                           continue
      */
     virtual void apply (X& x, Y& b, InverseOperatorResult& res) = 0;
 
@@ -107,6 +110,9 @@ namespace Dune
        \param b The right hand side
        \param reduction The minimum defect reduction to achieve.
        \param res Object to store the statistics about applying the operator.
+
+       \throw SolverAbort When the solver detects a problem and cannot
+                          continue
      */
     virtual void apply (X& x, Y& b, double reduction, InverseOperatorResult& res) = 0;