Doc update.

git-svn-id: https://svn.dealii.org/trunk@3121 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/lac/include/lac/solver_control.h b/deal.II/lac/include/lac/solver_control.h
index f2d9f25b0ba5b9c621772b60697be2949b89fec0..afb9a12a4512dae9148c9b1755db2eda8cfbd451 100644 (file)
--- a/deal.II/lac/include/lac/solver_control.h
+++ b/deal.II/lac/include/lac/solver_control.h
@@ -73,15 +73,17 @@ class SolverControl : public Subscriptor
                                      * tolerance to determine success
                                      * of the iteration.
                                      *
-                                     * @p{log_history} specifies whether
-                                     * the history (i.e. the value to
-                                     * be checked and the number of
-                                     * the iteration step) shall be
-                                     * printed to @p{deallog} stream.
-                                     * Default is: do not print. Similarly,
-                                     *  @p{log_result}
-                                     * specifies the whether the final result is logged
-                                     * to @p{deallog}. Default is yes.
+                                     * @p{log_history} specifies
+                                     * whether the history (i.e. the
+                                     * value to be checked and the
+                                     * number of the iteration step)
+                                     * shall be printed to
+                                     * @p{deallog} stream.  Default
+                                     * is: do not print. Similarly,
+                                     * @p{log_result} specifies the
+                                     * whether the final result is
+                                     * logged to @p{deallog}. Default
+                                     * is yes.
                                      */
     SolverControl (const unsigned int n = 100,
                   const double tol = 1.e-10,
@@ -128,12 +130,14 @@ class SolverControl : public Subscriptor
                                      * @p{last_value()} and
                                      * @p{last_step()}.
                                      *
-                                     * Derived classes may overload this
-                                     * function, e.g. to log the convergence
-                                     * indicators (@p{check_value}) or to do
+                                     * Derived classes may overload
+                                     * this function, e.g. to log the
+                                     * convergence indicators
+                                     * (@p{check_value}) or to do
                                      * other computations.
                                      */
-    virtual State check (const unsigned int step, const double check_value);
+    virtual State check (const unsigned int step,
+                        const double check_value);
 
                                     /**
                                      * Return the convergence value of last
@@ -163,6 +167,23 @@ class SolverControl : public Subscriptor
                                      * @p{ReturnState} @p{failure} if
                                      * @p{residual>failure_residual} with
                                      * @p{failure_residual:=rel_failure_residual*first_residual}.
+                                     *
+                                     * If a failure criterion was set
+                                     * using this method, then the
+                                     * iteration is also aborted if
+                                     * the residual becomes a
+                                     * denormalized value
+                                     * (@p{NaN}). Note, however, that
+                                     * this check is only performed
+                                     * if the @p{isnan} function is
+                                     * provided by the operating
+                                     * system, which is not always
+                                     * the case. The @p{configure}
+                                     * scripts checks for this and
+                                     * sets the flag @p{HAVE_ISNAN}
+                                     * in the file
+                                     * @p{Make.global_options} is
+                                     * this function was found.
                                      */
     void set_failure_criterion (const double rel_failure_residual);