ilog.concert

Interface IloLPMatrix

All Superinterfaces:

IloAddable, IloConstraint, IloIntExpr, IloNumExpr

public interface IloLPMatrix
extends IloConstraint

As a modeling object, an instance of IloLPMatrix allows you to treat a set of variables and range constraints (instances of IloRange) as a matrix.

Objects of this class represent a set of linear constraints of the form L <= A x <= U, where L and U are vectors and A is a matrix. This modeling object allows you to edit A directly as a sparse matrix.

Every row of an instance of IloLPMatrix corresponds to an instance of IloRange representing a linear constraint. Every column of this matrix is linked to an IloNumVar object. An IloNumVar object cannot be linked to more than one column of A. An IloRange object cannot be linked to more than one row of an IloLPMatrix. The rows of an LP matrix are referenced by integer values, called the row indices, ranging from 0 (zero) to getNrows-1. Similarly, the columns of an LP matrix are referenced by integer values, called the column indices, ranging from 0 (zero) to getNcols-1. Nonzero values in the LP matrix correspond to linear coefficients in the range constraints corresponding to its rows. For example, a nonzero coefficient A[i][j] in row i and column j is equivalent to the linear coefficient for the variable corresponding to column j of the LP matrix in the expression of the range constraint corresponding to row i of the LP matrix.

                  Column indices
               0  1  2  ....  n-1
              +--+--+--+--+--+--+
    r i   0   |  |  |  |  |  |  | ----->   IloRange ra;
    o n       +--+--+--+--+--+--+
    w d   1   |  |  |  |  |  |  | ----->   IloRange rb;
      i       +--+--+--+--+--+--+
      c   .   |  |  |  |  |  |  |   .
      e   .   +--+--+--+--+--+--+   .
      s   .   |  |  |  |  |  |  |   .
              +--+--+--+--+--+--+
          m-1 |  |  |  |  |  |  | ----->   IloRange rc;
              +--+--+--+--+--+--+
               |  |           |
               |  |    ...    |
               |  |           |
               V  V           V
    IloNumVar  x, y,   ...    z;
  

Create an instance of IloLPMatrix by calling the method IloMPModeler.LPMatrix or IloMPModeler.addLPMatrix. These methods create an empty instance of IloLPMatrix, that is, an LP matrix with 0 (zero) rows and 0 (zero) columns. Populate the LP matrix by using the methods addRow, addRows, addColumn, and addCols.

Although you can add multiple ranges (that is, instances of IloRange) and multiple variables (that is, instances of IloNumVar) to an instance of IloLPMatrix, it still remains a single modeling object. Any objects of IloRange or IloNumVar added to an instance of IloLPMatrix that is subsequently added to an instance of IloCplex are not directly accessible through the methods of IloCplex. For example, consider r1, an instance of IloRange added to an instance of IloLPMatrix subsequently added to an instance of IloCplex, and r2, an instance of IloRange added directly to the instance of IloCplex. The range r1 differs from the range r2; r1 cannot be modified directly by the methods of IloCplex; in contrast, you can use methods of IloCplex to modify r2.

See Also:

IloMPModeler.LPMatrix(), IloMPModeler.addLPMatrix()

Method Summary

Methods

Modifier and Type	Method and Description
int	addCols(IloNumVar[] var) Adds new empty columns to the LP matrix.
int	addCols(IloNumVar[] var, int[][] indices, double[][] values) Adds new columns to the LP matrix.
int	addCols(IloNumVar[] var, int start, int num) Adds new empty columns to the LP matrix.
int	addColumn(IloNumVar var) Adds a new empty column to an LP matrix.
int	addColumn(IloNumVar var, int[] ind, double[] val) Adds a new column to an LP matrix.
int	addRow(double lb, double ub, int[] ind, double[] val) Adds a new row to the LP matrix.
int	addRow(IloRange rng) Adds a range constraint as a new row to an LP matrix.
int	addRows(double[] lb, double[] ub, int[][] ind, double[][] val) Adds a set of new rows to LP matrix.
int	addRows(IloRange[] rng) Adds range constraints as new rows to an LP matrix.
int	addRows(IloRange[] rng, int start, int num) Adds a set of range constraints as new rows to an LP matrix.
void	clear() Removes all rows and columns from the invoking LP matrix.
void	getCols(int begin, int num, int[][] ind, double[][] val) Returns columns in a sparse matrix representation.
int	getIndex(IloNumVar var) Returns the column index corresponding to a variable in the invoking LP matrix.
int	getIndex(IloRange rng) Returns the row index corresponding to a ranged constraint in the invoking LP matrix.
int	getNcols() Returns the number of columns in the invoking LP matrix.
int	getNNZs() Returns the number of nonzeros in the invoking LP matrix.
int	getNrows() Returns the number of rows in the invoking LP matrix.
IloNumVar	getNumVar(int i) Returns the variable corresponding to the i-th column of the LP matrix.
IloNumVar[]	getNumVars() Returns an array of variables corresponding to the columns of the LP matrix.
double	getNZ(int row, int column) Returns the value of the matrix element row and col from the invoking LP matrix.
IloRange	getRange(int i) Returns the ranged constraint corresponding to the i-th row of the LP matrix.
IloRange[]	getRanges() Returns an array of range constraints corresponding to the rows of the LP matrix.
void	getRows(int start, int num, double[] lb, double[] ub, int[][] ind, double[][] val) Returns rows in a sparse matrix representation.
void	removeCols(int[] ind) Removes a set of columns from the invoking LP matrix.
void	removeCols(int[] ind, int start, int num) Removes a set of columns from the invoking LP matrix.
void	removeCols(int begin, int num) Remove a range of columns from the LP matrix.
void	removeColumn(int ind) Removes one column from the LP matrix.
void	removeRow(int ind) Removes one row from the LP matrix.
void	removeRows(int[] ind) Removes a set of rows from the invoking LP matrix.
void	removeRows(int[] ind, int start, int num) Removes as set of rows from the invoking LP matrix.
void	removeRows(int start, int num) Removes a range of rows from the LP matrix.
void	setNZ(int rowind, int colind, double val) Sets one nonzero of the coefficient matrix of the invoking LP matrix.
void	setNZs(int[] rowind, int[] colind, double[] val) Sets nonzero elements of the coefficient matrix of the invoking LP matrix.

Methods inherited from interface ilog.concert.IloAddable

getName, setName

Method Detail

getNcols

int getNcols()
             throws IloException

Returns the number of columns in the invoking LP matrix.

Throws:

IloException

Returns:

The number of columns in the invoking LP matrix.

getNrows

int getNrows()
             throws IloException

Returns the number of rows in the invoking LP matrix.

Throws:

IloException

Returns:

The number of rows in the invoking LP matrix.

getNNZs

int getNNZs()
            throws IloException

Returns the number of nonzeros in the invoking LP matrix.

Throws:

IloException

Returns:

The number of nonzeros in the invoking LP matrix.

getCols

void getCols(int begin,
           int num,
           int[][] ind,
           double[][] val)
             throws IloException

Returns columns in a sparse matrix representation.

For every column, an array of row indices and an array of values is returned, corresponding to the nonzeros in the specified columns.

Throws:

IloException

Parameters:

begin - The index of the first column being queried.

num - The number of consecutive columns being queried.

ind - An array of arrays of integers to where the row indices of the queried columns will be copied. The nonzero indices of column begin+i will be copied into an array returned as ind[i]. This array must be initialized at least to size num.

val - An array of arrays of doubles to where the nonzero coefficients of the queried columns will be copied. The nonzero values of column begin+i will be copied into an array returned as val[i]. This array must be initialized to at least size num.

getRows

void getRows(int start,
           int num,
           double[] lb,
           double[] ub,
           int[][] ind,
           double[][] val)
             throws IloException

Returns rows in a sparse matrix representation.

For every row, an array of column indices and an array of values is returned, corresponding to the nonzeros in the specified rows, as well as the bounds of the constraints corresponding to the queried rows. This implies that the expression of the range constraint of a queried row can be expressed as the scalar product of the values returned for the queried row and the variables corresponding to the column indices returned for the queried row.

Throws:

IloException

Parameters:

start - The index of the first row being queried.

num - The number of consecutive rows being queried.

lb - An array where to copy the lower bound values for the range constraints corresponding to the queried rows. The lower bound of the range corresponding to row begin+i will be returned as lb[i]. This array must be allocated at least length num.

ub - An array where to copy the upper bound values for the range constraints corresponding to the queried rows. The upper bound of the range corresponding to row begin+i will be returned as ub[i]. This array must be allocated at least length num.

ind - An array of arrays of integers to which the column indices of the queried rows will be copied. The nonzero indices of row begin+i will be copied into an array returned as ind[i]. This array must be initialized to at least size num.

val - An array of arrays of doubles to which the nonzero coefficients of the queried rows will be copied. The nonzero values of row begin+i will be copied into an array returned as val[i]. This array must be initialized to at least size num.

getNZ

double getNZ(int row,
           int column)
             throws IloException

Returns the value of the matrix element row and col from the invoking LP matrix.

Throws:

IloException

Parameters:

row - The row index of the matrix element to query.

column - The column index of the matrix element to query.

Returns:

The value of the matrix element.

getIndex

int getIndex(IloRange rng)
             throws IloException

Returns the row index corresponding to a ranged constraint in the invoking LP matrix.

If the constraint is not linked to any row of the invoking LP matrix, -1 is returned.

Throws:

IloException

Parameters:

rng - Ranged constraint for which to query the row index.

Returns:

The row index of a range constraint.

getRange

IloRange getRange(int i)
                  throws IloException

Returns the ranged constraint corresponding to the i-th row of the LP matrix.

Throws:

IloException

Parameters:

i - The row index of the ranged constraint to be queried.

Returns:

The ranged constraint corresponding to row i.

getRanges

IloRange[] getRanges()
                     throws IloException

Returns an array of range constraints corresponding to the rows of the LP matrix.

Throws:

IloException

Returns:

An array of range constraints corresponding to the rows of the LP matrix.

getIndex

int getIndex(IloNumVar var)
             throws IloException

Returns the column index corresponding to a variable in the invoking LP matrix.

If the variable is not linked to any column of the invoking LP matrix, -1 is returned.

Throws:

IloException

Parameters:

var - The variable whose column index is queried.

Returns:

The column index of the variable var.

getNumVar

IloNumVar getNumVar(int i)
                    throws IloException

Returns the variable corresponding to the i-th column of the LP matrix.

Throws:

IloException

Parameters:

i - The column index of the variable to be queried.

Returns:

The variable corresponding to column i.

getNumVars

IloNumVar[] getNumVars()
                       throws IloException

Returns an array of variables corresponding to the columns of the LP matrix.

Throws:

IloException

Returns:

An array of variables corresponding to the columns of the LP matrix.

addRow

int addRow(double lb,
         double ub,
         int[] ind,
         double[] val)
           throws IloException

Adds a new row to the LP matrix.

The row being added is represented in sparse matrix notation. That is, the nonzero coefficients of the new row are given as an array ind of column indices, and an array of corresponding values val. These arrays must match in length.

A new range constraint is implicitly constructed for the added row. Its lower and upper bound values are provided as parameters lb and ub. The expression of the implicitly added range constraint is the scalar product of the values specified by parameter val and the variables corresponding to the columns specified by parameter ind.

Throws:

IloException

Parameters:

lb - The lower bound for the newly created range constraint added as a new row to the invoking LP matrix.

ub - The upper bound for the newly created range constraint added as a new row to the invoking LP matrix.

ind - An array of column indices for the nonzeros of the new row. An index must appear at most one time, and must be in the range 0 through getNcols()-1.

val - An array of the corresponding values of the nonzeros of the row to be added.

Returns:

The row index of the new row.

addRows

int addRows(double[] lb,
          double[] ub,
          int[][] ind,
          double[][] val)
            throws IloException

Adds a set of new rows to LP matrix.

The rows being added are represented in sparse matrix notation. That is, the nonzero coefficients of the new rows are given as arrays of column indices and corresponding arrays of values. Each pair of corresponding arrays must match in length.

For each of the added rows, a new range constraint is implicitly constructed. The lower and upper bound value of the i-th newly created range constraint are provided in the arguments lb[i] and ub[i]. Its expression is the scalar product of the values specified in the array val[i] and the variables corresponding to the columns specified in the array ind[i].

Throws:

IloException

Parameters:

lb - An array of double values containing the lower bounds for the range constraints to be created and added as rows to the invoking LP matrix.

ub - An array of double values containing the upper bounds for the range constraints to be created and added as rows to the invoking LP matrix.

ind - An array or arrays of column indices for the nonzeros of the new rows. An index must appear at most one time for each new row and must be in the range 0 through getNcols()-1.

val - An array or arrays of the corresponding values of the nonzeros of the rows to be added.

Returns:

The row index of the first new row.

addRow

int addRow(IloRange rng)
           throws IloException

Adds a range constraint as a new row to an LP matrix.

The range to be added must have a linear expression. The added row of the LP matrix will contain the linear terms of the range expression as nonzeros. If the expression of the ranged constraint being added contains variables that do not correspond to columns of the invoking IloLPMatrix, new columns are automatically added as needed.

Throws:

IloException

Parameters:

rng - The range constraint that is to become the new row.

Returns:

The row index of the added row.

addRows

int addRows(IloRange[] rng)
            throws IloException

Adds range constraints as new rows to an LP matrix.

The ranges to be added must all have linear expressions. The added rows of the LP matrix will contain the linear terms of the range expression as nonzeros. If the expression of a ranged constraint being added contains variables that do not correspond to columns of the invoking IloLPMatrix, new columns are automatically added as needed.

Throws:

IloException

Parameters:

rng - The array of range constraints to be added as new rows.

Returns:

The row index of the first added row.

addRows

int addRows(IloRange[] rng,
          int start,
          int num)
            throws IloException

Adds a set of range constraints as new rows to an LP matrix.

The ranges to be added must all have linear expressions. The added rows of the LP matrix will contain the linear terms of the range expression as nonzeros. If the expression of a ranged constraint being added contains variables that do not correspond to columns of the invoking IloLPMatrix, new columns are automatically added as needed.

Throws:

IloException

Parameters:

rng - An array containing the range constraints to be added as new rows.

start - The index of the first range in rng to be added as a new row.

num - The number of consecutive ranges in rng to be added as new rows.

Returns:

The row index of the first added row.

removeRow

void removeRow(int ind)
               throws IloException

Removes one row from the LP matrix.

The remaining rows will be kept in the same order.

Throws:

IloException

Parameters:

ind - The index of the row to be removed.

removeRows

void removeRows(int start,
              int num)
                throws IloException

Removes a range of rows from the LP matrix.

The remaining rows will be kept in the same order.

Throws:

IloException

Parameters:

start - The index of the first row to be removed.

num - The number of consecutive rows to be removed.

removeRows

void removeRows(int[] ind)
                throws IloException

Removes a set of rows from the invoking LP matrix.

The indices of the rows to be removed are specified in the array ind. Rows that are not removed remain in their original order, but they are assigned new row indices from 0 to getNrows()-1.

Throws:

IloException

Parameters:

ind - An array containing row indices of the rows to be removed.

removeRows

void removeRows(int[] ind,
              int start,
              int num)
                throws IloException

Removes as set of rows from the invoking LP matrix.

The indices of the rows to be removed are specified in the array ind[start], ..., ind[start+num-1]. Rows that are not removed remain in their original order, but they are assigned new row indices from 0 (zero) to getNrows()-1.

Throws:

IloException

Parameters:

ind - An array containing row indices of the rows to be removed.

start - The first index in ind of the rows to be removed.

num - The number of consecutive indices in ind of the rows to be removed.

addColumn

int addColumn(IloNumVar var,
            int[] ind,
            double[] val)
              throws IloException

Adds a new column to an LP matrix.

The column being added is represented in sparse matrix notation. The nonzero coefficients of the new column are given as an array ind of row indices, and an array of corresponding values val. These arrays must match in length.

The added column is linked to the variable provided as parameter var. This variable must not originally be linked to a column of the invoking LP matrix.

Throws:

IloException

Parameters:

var - The variable to be linked with the added column.

ind - An array of row indices of the nonzeros of the new column. An index must appear at most one time and must be in the range 0 through getNrows()-1.

val - An array of the corresponding values of the nonzeros of the column to be added.

Returns:

The column index of the added column.

addColumn

int addColumn(IloNumVar var)
              throws IloException

Adds a new empty column to an LP matrix.

All elements in an empty column are 0 (zero). The added column is linked to the variable provided as parameter var. This variable must not originally be linked to a column of the invoking LP matrix.

Throws:

IloException

Parameters:

var - The variable to be linked with the new column.

Returns:

The column index of the added column.

addCols

int addCols(IloNumVar[] var,
          int[][] indices,
          double[][] values)
            throws IloException

Adds new columns to the LP matrix.

The columns being added are represented in sparse matrix notation. That is, the nonzero coefficients of the j-th new column to be added are provided by array ind[j] containing the row indices, and by array val[j] containing corresponding values. Each pair of arrays ind[j] and val[j] must match in length.

The added columns will be linked to the variables provided as parameter var. These variables must not currently be linked to a column of the invoking LP matrix, nor may a variable be listed more than once in var.

Throws:

IloException

Parameters:

var - An array of variables to be linked to the new columns.

indices - An array or arrays of row indices of the nonzeros of the new columns. An index must appear at most one time in each column and must be in the range 0(zero) through getNrows()-1.

values - An array or arrays containing the corresponding values of the nonzeros of the columns to be added.

Returns:

The column index of the first added column.

addCols

int addCols(IloNumVar[] var)
            throws IloException

Adds new empty columns to the LP matrix.

Empty columns have no nonzeros. The added columns will be linked to the variables provided as parameter var. These variables must not currently be linked to a column of the invoking LP matrix, nor may a variable be listed more than once in var.

Throws:

IloException

Parameters:

var - An array of variables to be linked to the new columns.

Returns:

The column index of the first added column.

addCols

int addCols(IloNumVar[] var,
          int start,
          int num)
            throws IloException

Adds new empty columns to the LP matrix.

Empty columns have no nonzeros. The added columns will be linked to the variables provided in parameter var. These variables must not currently be linked to a column of the invoking LP matrix, nor may a variable be listed more than once in var[start], ... var[start+num-1].

Throws:

IloException

Parameters:

var - An array containing the variables to be added as columns.

start - The first variable in var to be added.

num - The number of variables in var to be added.

Returns:

The column index of the first added column.

removeColumn

void removeColumn(int ind)
                  throws IloException

Removes one column from the LP matrix.

The remaining columns will be kept in the same order.

Throws:

IloException

Parameters:

ind - The index of the column to be removed.

removeCols

void removeCols(int begin,
              int num)
                throws IloException

Remove a range of columns from the LP matrix.

The remaining columns will be kept in the same order.

Throws:

IloException

Parameters:

begin - The index of the first column to be removed.

num - Number of columns to be removed.

removeCols

void removeCols(int[] ind)
                throws IloException

Removes a set of columns from the invoking LP matrix.

The indices of columns to be removed are specified in the array ind. Columns that are not removed remain in their original order but are assigned new column indices from 0 (zero) to getNcols-1.

Throws:

IloException

Parameters:

ind - An array containing the indices of the columns to be removed.

removeCols

void removeCols(int[] ind,
              int start,
              int num)
                throws IloException

Removes a set of columns from the invoking LP matrix.

The indices of columns to be removed are specified in the array ind[start], ..., ind[start+num-1]. Columns that are not removed remain in their original order but are assigned new column indices from 0 to getNcols()-1.

Throws:

IloException

Parameters:

ind - An array containing the indices of the columns to be removed.

start - The first index in ind of the columns to be removed.

num - The number of indices in ind of the columns to be removed.

clear

void clear()
           throws IloException

Removes all rows and columns from the invoking LP matrix.

Throws:

IloException

setNZ

void setNZ(int rowind,
         int colind,
         double val)
           throws IloException

Sets one nonzero of the coefficient matrix of the invoking LP matrix.

By doing this, you are implicitly changing the expression of the range constraint corresponding to the row index of the affected nonzero element.

Throws:

IloException

Parameters:

rowind - The row index of the matrix coefficient to be set.

colind - The column index of the matrix coefficient to be set.

val - The value of the matrix coefficient to be set.

setNZs

void setNZs(int[] rowind,
          int[] colind,
          double[] val)
            throws IloException

Sets nonzero elements of the coefficient matrix of the invoking LP matrix.

By doing this, you are implicitly changing the expressions of the range constraints corresponding to the row indices of the affected nonzero elements.

Throws:

IloException

Parameters:

rowind - An array containing the row indices of the matrix coefficients to be set.

colind - An array containing the column indices of the matrix coefficients to be set.

val - An array containing the values of the new matrix coefficients to be set.