====== Sub-set index list ======

A sub-set index list contains only a sub-set of the indices of another index list. One example of a sub-set is the built-in //radionuclides// index list.

One of the main uses of the sub-set index list is to remove unnecessary indices from the computations.

===== Example =====

Consider a model which deals with different types of pesticides. Thus, a [[Material|material]] is created for each pesticide. Important when modeling pesticides is also the water content, so water transport must be modelled as well.

^Materials^
|DDT      |
|ametryne |
|nicotine |
|propham  |
|Water    |

The equations for water transport are naturally very different from those of pesticide evolution, and for simplicity the model is divided into two parts.

Here two sub-sets of the //Materials// index list can be made: one sub-set that contains only water, and one containing the pesticides. The equations for water transport are given the //Water// sub-set index list and the others are given the //Pesticides// sub-set.

===== See also =====

  * [[Index_list|Index list]]