-Adding smoothers and solvers to MLD2P4
-
+Adding new smoothers and solvers to MLD2P4
+
@@ -53,37 +53,53 @@ original version by: Nikos Drakos, CBLU, University of Leeds
-Adding smoothers and solvers to MLD2P4
+Adding new smoothers and solvers to MLD2P4
-Da ampliare e completare - SALVATORE.
-
-
-Completely new smoother and/or solver classes derived from the
-base objects in the library may be used without recompiling the
-library itself. Once the new smoother/solver class has been
-developed, the user can declare a variable of that new type in the
-application, and pass that variable to the p%set(solver,info)
-call; the new solver object is then dynamically included in the
-preconditioner structure.
+Developers can add completely new smoother and/or solver classes
+derived from the base objects in the library may be used without
+recompiling the library itself. To do so it is necessary first to
+select the base type to be extended; in our experience, it is quite
+likely that the new application needs only require the definition of a
+``solver'' object, which is almost always acting only on the local
+part of the distributed matrix. The parallel actions required to
+connect the various solver objects are most often already provided by
+the Block Jacobi or the Additive Schwarz smoothers.
+To define a new solver, the developer will then have to define its
+components and methods, perhaps taking one of the predefined solvers
+as a starting point if possible.
-
-
-
-If the user has developed a new type of smoother and/or
-solver by extending one of the base MLD2P4 types, and has declared a
-variable of the new type in the main program, it is possible to pass
-the new smoother/solver variable to the setup routine as follows:
+Once the new smoother/solver class has been developed, to use it in
+the context of the multilevel preconditioners it is necessary to:
+
+
+- Declare in the application program a variable of the new type;
+
+- Pass that variable as the argument to the se routine as in the
+ following:
call p%set(smoother,info [,ilev, ilmax,pos])
call p%set(solver,info [,ilev, ilmax,pos])
-In this way, the variable will act as a mold to which the
-preconditioner will conform, even though the MLD2P4 library is not
-modified, and thus has no direct knowledge about the new type.
+
+- Link into the application executable the code implementing the
+ various methods.
+
+
+The new solver object is then dynamically included in the
+preconditioner structure, and will act as a mold to which the
+preconditioner will conform, even though the MLD2P4 library has not
+been modified to account for this new development.
+
+
+It is possible to define new values for the keyword WHAT in the
+set routines; if the library code does not recognize a keyword,
+it passes it down the composition hierarchy (levels containing
+smoothers containing solvers), so that it can be eventually caught by
+the new solver.
diff --git a/docs/html/node25.html b/docs/html/node25.html
index 31ff396e..a0e6da22 100644
--- a/docs/html/node25.html
+++ b/docs/html/node25.html
@@ -44,7 +44,7 @@ original version by: Nikos Drakos, CBLU, University of Leeds
Up: userhtml
Previous: Adding smoothers and solvers
+ HREF="node24.html">Adding new smoothers and
-The translation was initiated by Salvatore Filippone on 2017-04-21
+The translation was initiated by Salvatore Filippone on 2017-04-24