ampl Namespace

namespace ampl


class AMPL

An AMPL translator. An object of this class can be used to do the following tasks:

Run AMPL code. See ampl.AMPL.Eval.

Read models and data from files. See and ampl.AMPL.ReadData.

Solve optimization problems constructed from model and data (see ampl.AMPL.Solve).

Access single elements of an optimization problem. See the generic ampl.AMPL.GetEntity and the generic ampl.AMPL.GetVariable, ampl.AMPL.GetObjective, ampl.AMPL.GetConstraint, ampl.AMPL.GetSet and ampl.AMPL.GetParameter.

Access lists of available elements of an optimization problem. See ampl.AMPL.GetVariables, ampl.AMPL.GetObjectives, ampl.AMPL.GetConstraints, ampl.AMPL.GetSets and ampl.AMPL.GetParameters.

AMPL stores one or more problems which may consume substantial amount of memory. An AMPL object without any references to it will eventually be freed by the Java garbage collector and all the memory and other resources associated with it will be released. This includes any resources which are out of scope of the garbage collector such as open files or memory managed by the native code. Call ampl.AMPL.Close to release these resources explicitly.

The initialization of the Java representation of the AMPL entities (any class derived from ampl.Entities.Entity) is lazy and consists of two steps. When a function listing available elements is called, only a shallow list with names, types and declarations of the elements is populated. The same happens when a reference to a Java representation of one entity is obtained (through a call to ampl.AMPL.GetEntity or any other single entity factory function). When accessing any instance of an entity (through the methods 'get' of any class), the (memory hungry) list of instances for that entity is created.

Consistency is maintained automatically. Any command issued to the translator through ampl.AMPL.Eval and similar functions invalidates all entities, and any further access to any entity will require communication between the native translator and the Java code. Conversely, any operation called through the Java equivalent function, like fixing variables or solving the model will invalidate only the entities involved. A list of dependencies between entities is automatically updated.

Error handling is two-faced:

1. Errors coming from the underlying AMPL translator (e.g. syntax errors and warnings obtained calling the ampl.AMPL.Eval method) are handled by the event ampl.AMPL.Error. Note that by default the event is disabled. To enable it, call ampl.AMPL.EnableErrorAndWarningRouting.

2. Generic errors coming from misusing the API, which are detected in .NET, are thrown as exceptions.

The default implementation of the error handler throws exceptions on errors and prints to console on warnings.

The output of every user interaction with the underlying translator is handled by the event ampl.AMPL.Output, which is called at each block of output from the translator after the function ampl.AMPL.EnableOutputRouting is called.

class DataFrame

A DataFrame object, used to communicate data to and from the AMPL entities.

An object of this class can be used to do the following tasks:

Assign values to AMPL entities (once the DataFrame is populated, use ampl.AMPL.SetData to assign its values to the modelling entities in its columns)

Get values from AMPL, decoupling the values from the AMPL entities they originate via ampl.Entities.Entity.GetValues.

A DataFrame object can be created in various ways via the various constructors: create a skeleton manually specifiying the number of indexing columns and the column headers; get column names (and number of indexing columns) from entities of the API passing them directly to the appropriate constructor, get values from AMPL, decoupling the values from the AMPL entities they originate from (via ampl.Entities.Entity.GetValues()).

Populating a DataFrame object can be done adding row by row to a pre-existing skeleton via ampl.DataFrame.AddRow, setting whole columns of a pre-existing skeleton via ampl.DataFrame.SetColumn or adding columns (including indexing columns) via ampl.DataFrame.AddColumn. Modifying a DataFrame object can be done via ampl.DataFrame.SetColumn or via ampl.DataFrame.SetArray or ampl.DataFrame.SetMatrix Accessing data in a DataFrame can be done row by row using ampl.DataFrame.GetRow or by column via ampl.DataFrame.GetColumn.

class Column
class Row
class Environment

This class provides access to the environment variables and provides facilities to specify where to load the underlying AMPL interpreter.

class Instance

Represent an instance of a modelling entity

class SetInstance

A SetInstance object stores the information regarding a specific instance of a set.The instances can be accessed through the function ampl.Entities.Set.Get of the parent entity or through its indexer.

class Tuple

AMPL immutable tuple

class Variant

AMPL base type, can store a number or a string

class VariantRef

AMPL base type, can store a number or a string


interface IVariant
interface IVariantRef