parma_polyhedra_library::PIP_Problem Class Reference
[Java Language Interface]

A Parametric Integer Programming problem. More...

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List of all members.

Public Member Functions

 PIP_Problem (long dim)
 Builds a trivial PIP problem.
 PIP_Problem (long dim, Constraint_System cs, Variables_Set params)
 Builds a PIP problem from a sequence of constraints.
 PIP_Problem (PIP_Problem y)
 Builds a copy of y.
native void free ()
 Releases all resources managed by this, also resetting it to a null reference.
Functions that Do Not Modify the PIP_Problem

native long max_space_dimension ()
 Returns the maximum space dimension an PIP_Problem can handle.
native long space_dimension ()
 Returns the space dimension of the PIP problem.
native long number_of_parameter_space_dimensions ()
 Returns the number of parameter space dimensions of the PIP problem.
native Variables_Set parameter_space_dimensions ()
 Returns all the parameter space dimensions of problem pip.
native long get_big_parameter_dimension ()
 Returns the big parameter dimension of PIP problem pip.
native long number_of_constraints ()
 Returns the number of constraints defining the feasible region of pip.
native Constraint constraint_at_index (long dim)
 Returns the i-th constraint defining the feasible region of the PIP problem pip.
native Constraint_System constraints ()
 Returns the constraints .
native String ascii_dump ()
 Returns an ascii formatted internal representation of this.
native String toString ()
 Returns a string representation of this.
native long total_memory_in_bytes ()
 Returns the size in bytes of the memory occupied by the underlying C++ object.
native long external_memory_in_bytes ()
 Returns the size in bytes of the memory managed by the underlying C++ object.
native boolean OK ()
 Returns true if the pip problem is well formed, i.e., if it satisfies all its implementation invariants; returns 0 and perhaps makes some noise if broken. Useful for debugging purposes.
Functions that May Modify the PIP_Problem

native void clear ()
 Resets this to be equal to the trivial PIP problem.
native void add_space_dimensions_and_embed (long pip_vars, long pip_params)
 Adds pip_vars + pip_params new space dimensions and embeds the PIP problem in the new vector space.
native void add_to_parameter_space_dimensions (Variables_Set vars)
 Sets the space dimensions in vars to be parameter dimensions of the PIP problem.
native void set_big_parameter_dimension (long d)
 Sets the big parameter dimension of PIP problem to d.
native void add_constraint (Constraint c)
 Adds a copy of constraint c to the PIP problem.
native void add_constraints (Constraint_System cs)
 Adds a copy of the constraints in cs to the PIP problem.
Computing the Solution of the PIP_Problem

native boolean is_satisfiable ()
 Checks satisfiability of *this.
native PIP_Problem_Status solve ()
 Optimizes the PIP problem.
native PIP_Tree_Node solution ()
 Returns a solution for the PIP problem, if it exists.
native PIP_Tree_Node optimizing_solution ()
 Returns an optimizing solution for the PIP problem, if it exists.
Querying/Setting Control Parameters

native
PIP_Problem_Control_Parameter_Value 
get_pip_problem_control_parameter (PIP_Problem_Control_Parameter_Name name)
 Returns the value of control parameter name.
native void set_pip_problem_control_parameter (PIP_Problem_Control_Parameter_Value value)
 Sets control parameter value.

Protected Member Functions

native void finalize ()
 Releases all resources managed by this.

Private Member Functions

native void build_cpp_object (long dim)
 Builds the underlying C++ object.
native void build_cpp_object (long dim, Constraint_System cs, Variables_Set vars)
 Builds the underlying C++ object.
native void build_cpp_object (PIP_Problem y)
 Builds the underlying C++ object.

Detailed Description

A Parametric Integer Programming problem.

An object of this class encodes a parametric integer (linear) programming problem. The PIP problem is specified by providing:

Note that all problem variables and problem parameters are assumed to take non-negative integer values, so that there is no need to specify non-negativity constraints.

The class provides support for the (incremental) solution of the PIP problem based on variations of the revised simplex method and on Gomory cut generation techniques.

The solution for a PIP problem is the lexicographic minimum of the integer points of the feasible region, expressed in terms of the parameters. As the problem to be solved only involves non-negative variables and parameters, the problem will always be either unfeasible or optimizable.

As the feasibility and the solution value of a PIP problem depend on the values of the parameters, the solution is a binary decision tree, dividing the context parameter set into subsets. The tree nodes are of two kinds:

It may happen that a decision node has no false child. This means that there is no solution if at least one of the corresponding constraints is not satisfied. Decision nodes having two or more linear tests on the parameters cannot have a false child. Decision nodes always have a true child.

Both kinds of tree nodes may also contain the definition of extra parameters which are artificially introduced by the solver to enforce an integral solution. Such artificial parameters are defined by the integer division of a linear expression on the parameters by an integer coefficient.

By exploiting the incremental nature of the solver, it is possible to reuse part of the computational work already done when solving variants of a given PIP_Problem: currently, incremental resolution supports the addition of space dimensions, the addition of parameters and the addition of constraints.

Definition at line 97 of file PIP_Problem.java.


Constructor & Destructor Documentation

parma_polyhedra_library::PIP_Problem::PIP_Problem ( long  dim  )  [inline]

Builds a trivial PIP problem.

A trivial PIP problem requires to compute the lexicographic minimum on a vector space under no constraints and with no parameters: due to the implicit non-negativity constraints, the origin of the vector space is an optimal solution.

Parameters:
dim The dimension of the vector space enclosing *this (optional argument with default value $0$).
Exceptions:
std::length_error Thrown if dim exceeds max_space_dimension().

Definition at line 113 of file PIP_Problem.java.

References build_cpp_object().

parma_polyhedra_library::PIP_Problem::PIP_Problem ( long  dim,
Constraint_System  cs,
Variables_Set  params 
) [inline]

Builds a PIP problem from a sequence of constraints.

Builds a PIP problem having space dimension dim from the constraint system cs; the dimensions vars are interpreted as parameters.

Definition at line 123 of file PIP_Problem.java.

References build_cpp_object().

parma_polyhedra_library::PIP_Problem::PIP_Problem ( PIP_Problem  y  )  [inline]

Builds a copy of y.

Definition at line 128 of file PIP_Problem.java.

References build_cpp_object().


Member Function Documentation

native void parma_polyhedra_library::PIP_Problem::add_constraint ( Constraint  c  ) 

Adds a copy of constraint c to the PIP problem.

Exceptions:
std::invalid_argument Thrown if the constraint c is a strict inequality or if its space dimension is strictly greater than the space dimension of this.
native void parma_polyhedra_library::PIP_Problem::add_constraints ( Constraint_System  cs  ) 

Adds a copy of the constraints in cs to the PIP problem.

Exceptions:
std::invalid_argument Thrown if the constraint system cs contains any strict inequality or if its space dimension is strictly greater than the space dimension of *this.
native void parma_polyhedra_library::PIP_Problem::add_space_dimensions_and_embed ( long  pip_vars,
long  pip_params 
)

Adds pip_vars + pip_params new space dimensions and embeds the PIP problem in the new vector space.

Parameters:
pip_vars The number of space dimensions to add that are interpreted as PIP problem variables (i.e., non parameters). These are added before adding the pip_params parameters.
pip_params The number of space dimensions to add that are interpreted as PIP problem parameters. These are added after having added the pip_vars problem variables.

The new space dimensions will be those having the highest indexes in the new PIP problem; they are initially unconstrained.

native void parma_polyhedra_library::PIP_Problem::add_to_parameter_space_dimensions ( Variables_Set  vars  ) 

Sets the space dimensions in vars to be parameter dimensions of the PIP problem.

native String parma_polyhedra_library::PIP_Problem::ascii_dump (  ) 

Returns an ascii formatted internal representation of this.

native void parma_polyhedra_library::PIP_Problem::build_cpp_object ( PIP_Problem  y  )  [private]

Builds the underlying C++ object.

native void parma_polyhedra_library::PIP_Problem::build_cpp_object ( long  dim,
Constraint_System  cs,
Variables_Set  vars 
) [private]

Builds the underlying C++ object.

native void parma_polyhedra_library::PIP_Problem::build_cpp_object ( long  dim  )  [private]

Builds the underlying C++ object.

Referenced by PIP_Problem().

native void parma_polyhedra_library::PIP_Problem::clear (  ) 

Resets this to be equal to the trivial PIP problem.

The space dimension is reset to $0$.

native Constraint parma_polyhedra_library::PIP_Problem::constraint_at_index ( long  dim  ) 

Returns the i-th constraint defining the feasible region of the PIP problem pip.

native Constraint_System parma_polyhedra_library::PIP_Problem::constraints (  ) 

Returns the constraints .

native long parma_polyhedra_library::PIP_Problem::external_memory_in_bytes (  ) 

Returns the size in bytes of the memory managed by the underlying C++ object.

native void parma_polyhedra_library::PIP_Problem::finalize (  )  [protected]

Releases all resources managed by this.

native void parma_polyhedra_library::PIP_Problem::free (  ) 

Releases all resources managed by this, also resetting it to a null reference.

native long parma_polyhedra_library::PIP_Problem::get_big_parameter_dimension (  ) 

Returns the big parameter dimension of PIP problem pip.

native PIP_Problem_Control_Parameter_Value parma_polyhedra_library::PIP_Problem::get_pip_problem_control_parameter ( PIP_Problem_Control_Parameter_Name  name  ) 

Returns the value of control parameter name.

native boolean parma_polyhedra_library::PIP_Problem::is_satisfiable (  ) 

Checks satisfiability of *this.

Returns:
true if and only if the PIP problem is satisfiable.
native long parma_polyhedra_library::PIP_Problem::max_space_dimension (  ) 

Returns the maximum space dimension an PIP_Problem can handle.

native long parma_polyhedra_library::PIP_Problem::number_of_constraints (  ) 

Returns the number of constraints defining the feasible region of pip.

native long parma_polyhedra_library::PIP_Problem::number_of_parameter_space_dimensions (  ) 

Returns the number of parameter space dimensions of the PIP problem.

native boolean parma_polyhedra_library::PIP_Problem::OK (  ) 

Returns true if the pip problem is well formed, i.e., if it satisfies all its implementation invariants; returns 0 and perhaps makes some noise if broken. Useful for debugging purposes.

native PIP_Tree_Node parma_polyhedra_library::PIP_Problem::optimizing_solution (  ) 

Returns an optimizing solution for the PIP problem, if it exists.

native Variables_Set parma_polyhedra_library::PIP_Problem::parameter_space_dimensions (  ) 

Returns all the parameter space dimensions of problem pip.

native void parma_polyhedra_library::PIP_Problem::set_big_parameter_dimension ( long  d  ) 

Sets the big parameter dimension of PIP problem to d.

native void parma_polyhedra_library::PIP_Problem::set_pip_problem_control_parameter ( PIP_Problem_Control_Parameter_Value  value  ) 

Sets control parameter value.

native PIP_Tree_Node parma_polyhedra_library::PIP_Problem::solution (  ) 

Returns a solution for the PIP problem, if it exists.

native PIP_Problem_Status parma_polyhedra_library::PIP_Problem::solve (  ) 

Optimizes the PIP problem.

Solves the PIP problem, returning an exit status.

Returns:
UNFEASIBLE_PIP_PROBLEM if the PIP problem is not satisfiable; OPTIMIZED_PIP_PROBLEM if the PIP problem admits an optimal solution.
native long parma_polyhedra_library::PIP_Problem::space_dimension (  ) 

Returns the space dimension of the PIP problem.

native String parma_polyhedra_library::PIP_Problem::toString (  ) 

Returns a string representation of this.

native long parma_polyhedra_library::PIP_Problem::total_memory_in_bytes (  ) 

Returns the size in bytes of the memory occupied by the underlying C++ object.


The documentation for this class was generated from the following file:
Generated on Sun Feb 27 16:23:05 2011 for PPL Java Language Interface by  doxygen 1.6.3