drasys.or.mp.util
Class MPSWriter

java.lang.Object
  |
  +--java.io.Writer
        |
        +--java.io.PrintWriter
              |
              +--drasys.or.mp.util.MPSWriter

public class MPSWriter

extends java.io.PrintWriter

implements ProblemWriterI

Outputs a mathematical programming problem to an MPS stream. There are two predominate versions of the MPS format. An older format that uses fixed field records and a newer format that uses white-space delimited records. The fixed record format limits row/column names to eight characters and the delimited format allows names of arbitrary length. An MPS reader that reads delimited records can read fixed records with no changes if the row/column names don't contain embedded spaces. This class writes records using the fixed format if the names contain eight or fewer characters and uses the delimited format if they are longer.

Any value that is equal to zero to within the 'epsilon' parameter for the problem will not be written to the stream. Variables of type INTEGER and BOOLEAN will be grouped inside integer marker records in the columns section. Variables of type BOOLEAN will have either a 'BV' or a 'UP' record in the bounds section dependent on the value of 'useBooleanBound'. A RANGE constraint will be output as an EQUAL constraint in the rows section with the lower range in the right-hand-side section and upper-lower in the ranges section. If the problem has a non-null value for the 'lp.name' metadatum, a NAME record will be written with the value.

References:

Linear Programming
    Vasek Chvatal / Paperback / Published 1983
Integer and Combinatorial Optimization
    George L. Nemhauser, Laurence A. Wolsey / Paperback / Published 1988
Integer Programming
    Laurence A. Wolsey / Hardcover / Published 1998

Fields inherited from class java.io.PrintWriter

out

 

Fields inherited from class java.io.Writer

lock

 

Constructor Summary

MPSWriter(java.io.OutputStream out)

MPSWriter(java.io.OutputStream out, boolean autoFlush)

MPSWriter(java.io.Writer out)

MPSWriter(java.io.Writer out, boolean autoFlush)

 

Method Summary
void	setBoundName(java.lang.String name)           Sets the name to use for the bound row.
void	setObjectiveName(java.lang.String name)           Sets the name to use for the objective row.
void	setRangeName(java.lang.String name)           Sets the name to use for the range column.
void	setRightHandSideName(java.lang.String name)           Sets the name to use for the right-hand-side column.
void	setUseBooleanBound(boolean useBooleanBound)           If 'useBooleanBound' is 'true' then a variable of type BOOLEAN will be designated with a bound data record of type 'BV'.
void	setWriteMetadata(boolean writeMetadata)           If 'writeMetadata' is 'true' then the metadata will be written as comments.
void	writeProblem(ProblemI problem)           Writes 'problem' to an MPS formatted stream.

 

Methods inherited from class java.io.PrintWriter

checkError, close, flush, print, print, print, print, print, print, print, print, print, println, println, println, println, println, println, println, println, println, println, setError, write, write, write, write, write

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Constructor Detail

MPSWriter

public MPSWriter(java.io.OutputStream out)

MPSWriter

public MPSWriter(java.io.OutputStream out,
                 boolean autoFlush)

MPSWriter

public MPSWriter(java.io.Writer out)

MPSWriter

public MPSWriter(java.io.Writer out,
                 boolean autoFlush)

setUseBooleanBound

public void setUseBooleanBound(boolean useBooleanBound)

If 'useBooleanBound' is 'true' then a variable of type BOOLEAN will be designated with a bound data record of type 'BV'. If it is 'false' then a variable of type BOOLEAN will be designated with a bound data record of type 'UP' and a value of '1.0'. The default is to use a 'BV' record.

setWriteMetadata

public void setWriteMetadata(boolean writeMetadata)

If 'writeMetadata' is 'true' then the metadata will be written as comments. If it is 'false' then the metadata will not be written. The default is to write the metadata.

setRightHandSideName

public void setRightHandSideName(java.lang.String name)

Sets the name to use for the right-hand-side column. The default is 'RHS';

setObjectiveName

public void setObjectiveName(java.lang.String name)

Sets the name to use for the objective row. The default is 'OBJ';

setRangeName

public void setRangeName(java.lang.String name)

Sets the name to use for the range column. The default is 'RNG';

setBoundName

public void setBoundName(java.lang.String name)

Sets the name to use for the bound row. The default is 'BND';

writeProblem

public void writeProblem(ProblemI problem)
                  throws java.io.IOException

Writes 'problem' to an MPS formatted stream. If a variable or constraint has no name then an arbitrary name will generated.

Specified by:

writeProblem in interface ProblemWriterI