*** empty log message ***

Mesh/Field.cpp

@@ -217,7 +217,9 @@ class StructuredField : public Field
     text_format = false;
     options["TextFormat"] = new FieldOptionBool(text_format, "True for ASCII input "
 						"files, false for binary files\n"
-            "(4 bite signed integers for n, double precision floating points for v, D and O)",
+						"(4 bite signed integers for n, "
+						"double precision floating points "
+						"for v, D and O)",
 						&update_needed);
     data = 0;
   }
@@ -1000,8 +1002,14 @@ class PostViewField : public Field
     view_index = 0;
     options["IView"] = new FieldOptionInt(view_index, "Post-processing view index",
 					  &update_needed);
-    crop_negative_values=true;
-    options["CropNegativeValues"] = new FieldOptionBool(crop_negative_values,"return LC_MAX instead of a negative value (this option is needed for backward compatibility with the BackgroundMesh option",&update_needed);
+    crop_negative_values = true;
+    options["CropNegativeValues"] = new FieldOptionBool(crop_negative_values, 
+							"return LC_MAX instead of a "
+							"negative value (this option "
+							"is needed for backward "
+							"compatibility with the "
+							"BackgroundMesh option",
+							&update_needed);
   }
   ~PostViewField()
   {

demos/fields.geo

@@ -3,21 +3,24 @@ Point(1) = {0.0,0.0,0,lc};
 Point(2) = {1,0.0,0,lc};
 Point(3) = {1,1,0,lc};
 Point(4) = {0,1,0,lc};
+Point(5) = {0.2,.5,0,lc};
 Line(1) = {3,2};
 Line(2) = {2,1};
 Line(3) = {1,4};
 Line(4) = {4,3};
-Point(55) = {0.2,.5,0,lc};
 Line Loop(5) = {1,2,3,4};
 Plane Surface(6) = {5};
 
-// Attractors field on points 1 and 55, and on line 1
+// Attractor field on points 5 and on line 1. This field returns the
+// distance to point 5 and to (100 equidistant points on) line 1.
 Field[1] = Attractor;
+Field[1].NodesList = {5};
 Field[1].NNodesByEdge = 100;
-Field[1].NodesList = {1,55};
 Field[1].EdgesList = {1};
 
-// Threshold field defined on the attractors
+// Threshold field using the return value of the attractor field 1 in
+// order to define a simple change in element size around the
+// attractors (i.e., around point 5 and line 1)
 //
 // LcMax -                         /------------------
 //                               /
@@ -28,18 +31,38 @@ Field[1].EdgesList = {1};
 //     Attractor       DistMin   DistMax
 Field[2] = Threshold;
 Field[2].IField = 1;
-Field[2].LcMin = lc/20;
+Field[2].LcMin = lc / 30;
 Field[2].LcMax = lc;
 Field[2].DistMin = 0.15;
 Field[2].DistMax = 0.5;
-//Field[2].Sigmoid = 1;
 
-// Function field
+// MathEval field with a function depending on the model coordinates
 Field[3] = MathEval;
 Field[3].F = "Cos(4*3.14*x) * Sin(4*3.14*y) / 10 + 0.101";
 
-// Use minimum of threshold and function field as background field
-Field[4] = Min;
-Field[4].FieldsList = {2, 3};
+// Attractor around point 1
+Field[4] = Attractor;
+Field[4].NodesList = {1};
 
-Background Field = 4;
+// MathEval field with a function depending on the return value of the
+// attractr field 4, i.e., depending on the distance to point 1 (here
+// using a cubic law, with minumum element size = lc / 100)
+Field[5] = MathEval;
+Field[5].F = Sprintf("F4^3 + %g", lc / 100);
+
+// Box field to impose a step change in element sizes inside a box
+Field[6] = Box;
+Field[6].VIn = lc / 15;
+Field[6].VOut = lc;
+Field[6].XMin = 0.3; 
+Field[6].XMax = 0.6;
+Field[6].YMin = 0.3;
+Field[6].YMax = 0.6;
+
+// Use minimum of all the fields as the background field
+Field[7] = Min;
+Field[7].FieldsList = {2, 3, 5, 6};
+Background Field = 7;
+
+// Don't extend the elements sizes from the boundary inside the domain
+Mesh.CharacteristicLengthExtendFromBoundary = 0;

doc/texinfo/opt_fields.texi

@@ -6,7 +6,7 @@
 @ftable @code
 @item Attractor
 Compute the distance from the nearest node in a list. It can also be used to compute distance from curves, in this case each curve is replaced by NNodesByEdge equidistant nodes and the distance from those nodes is computed. @*
-The ANN library is used to find the nearest node : http://www.cs.umd.edu/~mount/ANN/ @*
+The ANN library is used to find the nearest node: http://www.cs.umd.edu/~mount/ANN/ @*
 Options:@*
 @table @code
 @item EdgesList
@@ -146,7 +146,7 @@ default value: @code{@{@}}
 @end table
 
 @item MaxEigenHessian
-Compute the maximum eigen value of the Hessian matrix of Field[IField]. Gradients are evaluated by finite differences, eigenvalues are computed using the GSL library.@*
+Compute the maximum eigen value of the Hessian matrix of Field[IField]. Gradients are evaluated by finite differences, eigenvalues are computed using the GSL library.F = max ( eigenvalues ( grad ( grad ( Field[IField] ) ) ) ) @*
 Options:@*
 @table @code
 @item Delta
@@ -217,6 +217,28 @@ type: integer@*
 default value: @code{0}
 @end table
 
+@item Restrict
+Restrict the application of a field to a given list of geometrical curves, surfaces or volumes. @*
+Options:@*
+@table @code
+@item EdgesList
+Curve indices@*
+type: list@*
+default value: @code{@{@}}
+@item FacesList
+Surface indices@*
+type: list@*
+default value: @code{@{@}}
+@item IField
+Field index@*
+type: integer@*
+default value: @code{1}
+@item RegionsList
+Volume indices@*
+type: list@*
+default value: @code{@{@}}
+@end table
+
 @item Structured
 Linearly interpolate between data provided on a 3D rectangular structured grid. The format of the input file is : @*
 Ox Oy Oz @*