Contents

• Contents
• Constant and indexed fields
• CellML integration
• Components

Constant and indexed fields

In CMISS currently a field that is defined as a constant for a region is still actually defined individually on each element and node. Richard and I reckon that it is more sensible that a constant field defined on a region applies to and is defined on all entities in that region. Sometimes a quantity, say a cell parameter, is a constant but is only defined on a subset of the cells (represented by nodes). The definition of a constant just stated would not allow this.

Instead an indexed field could be used. The field has several values which are constant for the entire field but each object in the field has an integer field which selects which one of the whole field constants applies to that object. This also means that a entity that does not define a value for the integer field will not have a value for the indexed field.

   <fieldml xmlns:fieldml="http://www.physiome.org.nz/fieldml/0.1#" xmlns="http://www.physiome.org.nz/fieldml/0.1#">
     <field name="conductivity" value_type="real" coordinate_system="rectangular cartesian">
      0.235234          
     </field>

     <field name="home" value_type="real" coordinate_system="rectangular cartesian">
       <component name="latitude">
        -41.00
       </component>
       <component name="longitude">
        174.00
       </component>
     </field>
   </fieldml>

CellML integration

David Nickerson is updating the export of cells from his CellML computation in CMISS and is now considering using this new definition of Fieldml to store his values (and hence prompted the discussion above).

Components

Components are a restrictive grouping of different field quantities. It may be preferable that every component is just a field in it's own right and that you can group fields together to form fields with more quantities.