VariableInstance
================

.. java:package:: com.ampl
   :noindex:

.. java:type:: public class VariableInstance extends BasicInstance<VariableInstanceBase>

   A decision variable instance. Each member of this class belongs to a single \ :java:ref:`Variable`\ . Note that accessors available here are replicated at \ :java:ref:`Variable`\  level for ease of use when dealing with scalar variables.

   All AMPL suffixes for an algebraic variable are available through methods with the same name in this class. See http://www.ampl.com/NEW/suffbuiltin.html for a list of the available suffixes.

   All the accessors in this class throw a :java:ref:`IllegalArgumentException` if the instance has been deleted in the underlying AMPL interpreter.

Constructors
------------
VariableInstance
^^^^^^^^^^^^^^^^

.. java:constructor::  VariableInstance(VariableInstanceBase impl)
   :outertype: VariableInstance

Methods
-------
astatus
^^^^^^^

.. java:method:: public String astatus()
   :outertype: VariableInstance

   Get the AMPL status (fixed, presolved, or substituted out)

defeqn
^^^^^^

.. java:method:: public int defeqn()
   :outertype: VariableInstance

   Get the index in \ ``_con``\  of "defining constraint" used to substitute variable out

dual
^^^^

.. java:method:: public double dual()
   :outertype: VariableInstance

   Get the dual value on defining constraint of variable substituted out

fix
^^^

.. java:method:: public void fix()
   :outertype: VariableInstance

   Fix all instances of this variable to their current value, equivalent to:

   .. parsed-literal::

      fix varname;

fix
^^^

.. java:method:: public void fix(double value)
   :outertype: VariableInstance

   (for scalar variables) fix the variable to the specified value, equivalent to:

   .. parsed-literal::

      fix varname := value;

impl
^^^^

.. java:method::  VariableInstanceBase impl()
   :outertype: VariableInstance

init
^^^^

.. java:method:: public double init()
   :outertype: VariableInstance

   Get the current initial guess

init0
^^^^^

.. java:method:: public double init0()
   :outertype: VariableInstance

   Get the original initial guess (set by \ ``:=``\  or \ ``default``\  or by a data statement)

lb
^^

.. java:method:: public double lb()
   :outertype: VariableInstance

   Returns the current lower bound. See :ref:`secVariableSuffixesNotes`.

lb0
^^^

.. java:method:: public double lb0()
   :outertype: VariableInstance

   Returns the initial lower bounds, from the var declaration

lb1
^^^

.. java:method:: public double lb1()
   :outertype: VariableInstance

   Returns the weaker lower bound from AMPL's presolve phase

lb2
^^^

.. java:method:: public double lb2()
   :outertype: VariableInstance

   Returns the stronger lower bound from AMPL's presolve phase

lrc
^^^

.. java:method:: public double lrc()
   :outertype: VariableInstance

   Returns the reduced cost at lower bound

lslack
^^^^^^

.. java:method:: public double lslack()
   :outertype: VariableInstance

   Return the slack at lower bound (\ ``val - lb``\ ). See :ref:`secVariableSuffixesNotes`.

rc
^^

.. java:method:: public double rc()
   :outertype: VariableInstance

   Get the reduced cost (at the nearer bound)

setValue
^^^^^^^^

.. java:method:: public void setValue(double value)
   :outertype: VariableInstance

   Set the current value of this variable instance

   :param value: Value to be set

slack
^^^^^

.. java:method:: public double slack()
   :outertype: VariableInstance

   Returns the bound slack which is the lesser of :java:ref:`lslack` and :java:ref:`uslack`. See :ref:`secVariableSuffixesNotes`.

sstatus
^^^^^^^

.. java:method:: public String sstatus()
   :outertype: VariableInstance

   Solver status (basis status of variable)

status
^^^^^^

.. java:method:: public String status()
   :outertype: VariableInstance

   AMPL status if not \ ``in``\ , otherwise solver status

ub
^^

.. java:method:: public double ub()
   :outertype: VariableInstance

   Returns the current upper bound. See :ref:`secVariableSuffixesNotes`.

ub0
^^^

.. java:method:: public double ub0()
   :outertype: VariableInstance

   Returns the initial upper bound, from the var declaration

ub1
^^^

.. java:method:: public double ub1()
   :outertype: VariableInstance

   Returns the weaker upper bound from AMPL's presolve phase

ub2
^^^

.. java:method:: public double ub2()
   :outertype: VariableInstance

   Returns the stronger upper bound from AMPL's presolve phase

unfix
^^^^^

.. java:method:: public void unfix()
   :outertype: VariableInstance

   Unfix all instances of the current variable, equivalent to the AMPL code:

   .. parsed-literal::

      unfix varname;

urc
^^^

.. java:method:: public double urc()
   :outertype: VariableInstance

   Returns the reduced cost at upper bound

uslack
^^^^^^

.. java:method:: public double uslack()
   :outertype: VariableInstance

   Return the slack at upper bound (\ ``ub - val``\ ). See :ref:`secVariableSuffixesNotes`.

value
^^^^^

.. java:method:: public double value()
   :outertype: VariableInstance

   Get the current value of this variable instance