Entity Class
An AMPL entity such as a parameter or a variable.
An entity can either represent a single instance of an AMPL algebraic entity
or, if the corresponding declaration has an indexing expression, a mapping
from keys to instances.In the derived classes, it has methods to access
instance-level properties which can be used in case the represented entity is
scalar.
To gain access to all the values in an entity (for all instances and all
suffixes for that entities), use the function ampl.Entities.Entity.GetValues()
.
The algebraic entities which currenty have an equivalent class in the API are:
Variables (see ampl.Entities.Variable
)
Constraints (see ampl.Entities.Constraint
)
Objectives (see ampl.Entities.Objective
)
Sets (see ampl.Entities.Set
)
Parameters (see ampl.Entities.Parameter
)
- Namespace
ampl.Entities
- Assemblies
-
public class Entity : IEnumerable
-
class ampl.Entities.Entity
-
GetEnumerator()
- Return type
System.Collections.IEnumerator
public virtual IEnumerator GetEnumerator()
-
GetValues()
Get the principal values of this entity as a DataFrame. The specific returned
value depends on the
type of entity(see list below).
For:
Variables and Objectives it returns the suffix val
Parameters it returns their values
Constraints it returns the suffix dual
Sets it returns all the members of the set, Note that it does not apply to indexed sets. See ampl.SetInstance.GetValues
- Return type
ampl.DataFrame
- Returns
A DataFrame containing the values for all instances
public virtual DataFrame GetValues()
-
GetValues(System.String[])
Get the specified suffixes value for all instances in a DataFrame
- Arguments
suffixes (System.String<System.String>[]) – Suffixes to get
- Return type
ampl.DataFrame
- Returns
A DataFrame containing the specified values
public DataFrame GetValues(params string[] suffixes)
-
SetValues(ampl.DataFrame)
Set the values of this entiy to the correponding values of a
DataFrame indexed over the same sets(or a subset).
This function assigns the values in the first data column of
the passed dataframe to the entity the function is called from.
In particular, the statement:
`x.SetValues(y.GetValues());`
is semantically equivalent to the AMPL statement:
`let { s in S } x[s] := y[s];`
- Arguments
data (ampl.DataFrame) – The data to set the entity to
public void SetValues(DataFrame data)
-
ToString()
Returns a textual representation of this entity
- Return type
System.String
public override string ToString()
-
ampl.Entities.Entity.Indexarity
Get the indexarity of this entity (sum of the dimensions of the indexing
sets).
This value indicates the arity of the tuple to be passed to the method
ampl.Entities.Entity.Get
in order to access an instance of this entity.
See the following AMPL examples:
var x; # indexarity = 0
var y {1..2}; # indexarity = 1
var z {1..2,3..4}; # indexarity = 2
var zz {{ (1, 2)} }; # indexarity = 2
Get the sum of the dimensions of the indexing sets or 0 if the
entity is not indexed
- Return type
System.Int32
public int Indexarity { get; }
-
ampl.Entities.Entity.IndexingSets
Get the AMPL string representation of the sets on which this entity is
indexed.The obtained vector can be modified without any effect to the
entity.
Is equal to the string representation of the indexing sets for this entity or
an empty array if the entity is scalar
- Return type
System.String<System.String>[]
public string[] IndexingSets { get; }
-
ampl.Entities.Entity.IsScalar
Check whether this entity is scalar. Equivalent to testing whether
indexarity is equal to zero, is true if the entity is scalar
(not indexed over any set)
- Return type
System.Boolean
public bool IsScalar { get; }
-
ampl.Entities.Entity.Name
Get the name of this entity
- Return type
System.String
public string Name { get; }
-
ampl.Entities.Entity.NumInstances
Get the number of instances in this entity
- Return type
System.Int32
public int NumInstances { get; }
-
ampl.Entities.Entity.XRef
Get the names of all entities which depend on this one.
- Return type
System.String<System.String>[]
public string[] XRef { get; }