====== Mapped index list ======

The indices of a mapped index lists are mapped to another index list, and make it possible to create categories of indices. A typical example in the world of radio physics is the mapping of isotopes to elements.

==== Example ====

Assume you have created an index list for different types of //Animals//. This index list is used when calculating the life expectancy of different animals, and means that your model contains a long list of complicated expressions that are using it.

^Animals^
|Lion   |
|Lamb   |
|Cow    |
|Python |
|Pike   |

One of the essential factors in life expectancy prediction is the //digestion// parameter. The parameter can be approximated to be the same for all carnivores, and the same for all herbivores.

Rather than using the //Animals// index list for the parameter, which would mean having to enter the same value in many places, you can create a new index list named //Diet//:

^Diet     ^
|herbivore|
|carnivore|

The list can then be mapped to the //Animals// index list as such:

^Animals^Diet     ^
|Lion   |carnivore|
|Lamb   |herbivore|
|Cow    |herbivore|
|Python |carnivore|
|Pike   |carnivore|

The //digestion// [[Parameter|parameter]] can now be assigned the //Diet// index list. When the [[Parameter|parameter]] is used by an [[Expression|expression]] which is vectorized using the //Animals// index list, Ecolego will automatically use values corresponding to the mapping.

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

  * [[Index_list|Index list]]