Entity#

class Entity#

This is the base class for all entities (Variable , Constraint, Objective, Parameter, Set). It can be used directly in methods such as AMPL.getEntity, and it has the basic functionality shared for all Entity classes.

get(key)#

classmethod Entity.get(key)#

Syntax#

v = get(key)

Description#

v = get(key) returns the instance corresponding to the specified key. Examples will be given for each specialized Entity class. Note that the same effect can be achieved using MATLAB’s indexing operator (round brackets).

Input Arguments#

key: The key of the instance to look up.

Output Arguments#

v: The specified instance

getValues#

classmethod Entity.getValues()#

Syntax#

df = c.getValues()

df = c.getValues(suffixes)

Description#

These functions return a dataframe with all the specified values of the entity, decoupled from the underlying AMPL. To gain access to the data, see DataFrame.

c.getValues() gets the AMPL value (the default suffix for the current entity)

c.getValues(suffixes) allows the user to specify which suffixes to get

Input Arguments#

suffixes: Strings specifying which suffixes of the entity to get (see AMPL built-in suffixes).

Output Arguments#

df: A dataframe containing all the specified values of the entity and its indices

hasIndexing#

classmethod Entity.hasIndexing()#

Syntax#

bool = hasIndexing

Description#

hasIndexing check whether this entity has indexing or is scalar

Output Arguments#

bool: 1 if the entity has indexing, 0 if it is scalar

indexarity#

classmethod Entity.indexarity()#

Syntax#

integer = indexarity

Description#

indexarity Get the indexarity of this entity

Output Arguments#

integer: The indexarity of this function, defined as the number of items necessary to access an instance of this entity

Example#

Indexarity of some functions:

ampl.eval('var x; var y{1..10}; var z{1..2, 3..4, 4..5};');
ampl.getEntity('x').indexarity
ampl.getEntity('y').indexarity
ampl.getEntity('z').indexarity

gives:

ans = 0
    ans = 1
    ans = 3

name#

classmethod Entity.name()#

Syntax#

n = name

Description#

name Access the name of this entity

Output Arguments#

n: The AMPL name (without indexing) of this entity

getIndices#

classmethod Entity.getIndices()#

Syntax#

indices = getIndices

Description#

getIndices get a cell array containing all the indices over which this entity is currently istantiated