Index: /trunk/src/transform_field/sub_field.m
===================================================================
--- /trunk/src/transform_field/sub_field.m	(revision 519)
+++ /trunk/src/transform_field/sub_field.m	(revision 519)
@@ -0,0 +1,23 @@
+%'sub_field': combines two input fields
+%
+% the two fields are subtstracted when of the same nature (scalar or
+% vector), if the coordinates do not coincide, the second field is
+% interpolated on the cooridintes of the first one
+%
+% when scalar and vectors are combined, the fields are just merged in a single matlab structure for common visualisation
+%-----------------------------------------------------------------------
+% function SubData=sub_field(Field,XmlData,Field_1)
+%
+% OUPUT: 
+% SubData: structure representing the resulting field
+%
+% INPUT: 
+% Field: matlab structure representing the first field
+% Field_1:matlab structure representing the second field
+
+function SubData=sub_field(Field,XmlData,Field_1)
+if exist('Field_1','var')
+SubData=sub_field(Field,XmlData,Field_1);
+else
+    SubData=[];
+end