Updating README.md

README.md

@@ -61,36 +61,69 @@ Giambellino 7, 35129 Padova, Italy);
   at [University of Padova](https://www.unipd.it/en).
 
 ## Parameters ##
-The parameters needed to set-up the AMG preconditioner in ChronosLab are the following:
-
-* **problem type** can be either **mech** or **lapl** and denotes the origin of the linear
-  system at hand. The first one sets the default for mechanical problems, the second one
-  for system arising from the discretization of Laplace equations.
-* **tspace_ntv** is the number of test vector (approximation of the near kernel) of the problem
-  at hand. In general the size of the test space equals the size of the test space that is
-  given as input but can be overwritten by the user through **tspace_ntv**. If there is no
-  test space as input, the default value is 1.
-* **tspace_iter** is the number of iterations of SRQCG (Simultaneous minimization of
-  the Rayleight Quotient though CG). By default the number of iterations is 0.
-* **smooth_type** defines the type of smoother that is used. Possible values are **jacobi**,
-  **ligthFSAI**, **mediumFSAI**, **heavyFSAI** and **nestFSAI**. The first one is the simple
-  Jacobi preconditioner. Those from light to heavy denote different FSAI set-up from the
-  cheapest and less accurate to the more expensive and more accurate. The last one denotes
-  a novel type to compute FSAI that is recommended for highly ill-conditioned problems.
-* **coars_tau** is the strength of connection threshold that is used for coarsening. In case
-  of **mech** problems, the symmetric strength of connection is used with default 0.01.
-  In case of **lapl** problems, the classical strength of connection is used with default
-  0.25.
-* **prolo_smooth** is a parameter used only for **mech** problems and can take value **none**
-  if the prolongation is not improved by smoothing, **smooth** if the prolongation is smoothed
-  and **emin** if the prolongation is improved by energy minimization. The default value is
-  **emin**
-
-There are other parameters in ChronosLab that an advanced user can access to better tune
-the AMG set-up on the problem at hand. These parameters and their meaning can be found by
-inspecting the main driver in each folder (e.g. coarsen.m in the folder coarsen, tspace.m
-in the folder tspace, etc.). Moreover the FSAI smoother can be also used as stand-alone
-preconditioner.
+The parameters needed to set-up the AMG preconditioner in ChronosLab are the
+following:
+
+* **problem type** can be either **mech** or **lapl** and denotes the origin of
+  the linear system at hand. The first one sets the default for mechanical
+  problems, the second one for system arising from the discretization of
+  Laplace equations.
+* **tspace_ntv** is the number of test vector (approximation of the near
+  kernel) of the problem at hand. In general the size of the test space equals
+  the size of the test space that is given as input but can be overwritten by
+  the user through **tspace_ntv**. If there is no test space as input, the
+  default value is 1.
+* **tspace_iter** is the number of iterations of SRQCG (Simultaneous
+  minimization of the Rayleight Quotient though CG). By default the number of
+  iterations is 0.
+* **smooth_type** defines the type of smoother that is used. Possible values
+  are **jacobi**, **ligthFSAI**, **mediumFSAI**, **heavyFSAI** and
+  **nestFSAI**. The first one is the simple Jacobi preconditioner. Those from
+  light to heavy denote different FSAI set-up from the cheapest and less
+  accurate to the more expensive and more accurate. The last one denotes a
+  novel type to compute FSAI that is recommended for highly ill-conditioned
+  problems.
+* **coars_tau** is the strength of connection threshold that is used for
+  coarsening. In case of **mech** problems, the symmetric strength of
+  connection is used with default 0.01. In case of **lapl** problems, the
+  classical strength of connection is used with default 0.25.
+* **prolo_smooth** is a parameter used only for **mech** problems and can take
+  value **none** if the prolongation is not improved by smoothing, **smooth**
+  if the prolongation is smoothed and **emin** if the prolongation is improved
+  by energy minimization. The default value is **emin**.
+
+There are other parameters in ChronosLab that an advanced user can access to
+better tune the AMG set-up on the problem at hand. These parameters and their
+meaning can be found by inspecting the main driver in each folder (e.g.
+coarsen.m in the folder coarsen, tspace.m in the folder tspace, etc.). Moreover
+the FSAI smoother can be also used as stand-alone preconditioner.
+
+Here two examples of input file. The first one for a structural problem:
+
+```xml
+<ChronosLab>
+  <problem type="mech"/>
+  <preconditioner
+    tspace_ntv="6"
+    smooth_type="mediumFSAI"
+    coars_tau="0.01"
+    prolo_smooth="EMIN"
+  />
+</ChronosLab>
+```
+
+while the next is for linear system arising from the Laplace equation:
+
+```xml
+<ChronosLab>
+  <problem type="lapl"/>
+  <preconditioner
+    tspace_ntv="1"
+    smooth_type="lightFSAI"
+    coars_tau="0.25"
+  />
+</ChronosLab>
+```
 
 ## Terms of usage ##
 **ChronosLab** is an open source software under the MIT license and can be

examples/lapl/config.xml

@@ -1,11 +1,8 @@
 <ChronosLab>
-  <problem
-    type="lapl"
-  />
+  <problem type="lapl"/>
   <preconditioner
     tspace_ntv="1"
     smooth_type="lightFSAI"
-    coars_tau="-30.0"
-    prolo_smooth="EMIN"
+    coars_tau="0.25"
   />
 </ChronosLab>

examples/mech/config.xml

@@ -1,13 +1,10 @@
 <ChronosLab>
-  <problem
-    type="mech"
-  />
-
-  <!--preconditioner
+  <problem type="mech"/>
+  <preconditioner
     tspace_ntv="6"
     tspace_iter="100"
     smooth_type="lightFSAI"
-    coars_tau="-30.0"
+    coars_tau="0.01"
     prolo_smooth="EMIN"
-  /!-->
+  />
 </ChronosLab>