Class WeightedStaticScheduling
 java.lang.Object

 org.cicirello.search.problems.scheduling.WeightedStaticScheduling

 All Implemented Interfaces:
SingleMachineSchedulingProblemData
public final class WeightedStaticScheduling extends Object implements SingleMachineSchedulingProblemData
This class provides a representation of, and means of generating, instances of single machine scheduling problems involving weights and due dates, but without release dates (i.e., all jobs are released at the start of the problem at time 0, thus, the term "static" in the class name).
This class generates instances using a procedure based on that used to generate the benchmark instances for weighted tardiness scheduling that are available in the ORLibrary of J.E. Beasley. Note that this is NOT the implementation that generated those instances. Rather, this implementation is based on the description of that generator. That description, along with a set of benchmark instances, is mirrored in the following GitHub repository: https://github.com/cicirello/schedulingbenchmarks
The ChipsnSalsa library separates the representation of the scheduling problem instance data (e.g., processing times, weights, etc) from the implementations of scheduling cost functions deliberately to enable defining additional problems (i.e., different cost functions to optimize) using the same scheduling problem generators. This is very much like what was suggested in the following paper:
 Vincent A. Cicirello. The Challenge of SequenceDependent Setups: Proposal for a Scheduling Competition Track on One Machine Sequencing Problems. Proceedings of the International Conference on Automated Planning and Scheduling (ICAPS) Workshop on Scheduling a Scheduling Competition. AAAI Press, September 2007.


Field Summary
Fields Modifier and Type Field Description static int
MAX_PROCESS_TIME
Defines the maximum process times.static int
MAX_WEIGHT
Defines the maximum weight.static int
MIN_PROCESS_TIME
Defines the minimum process times.static int
MIN_WEIGHT
Defines the minimum weight.

Constructor Summary
Constructors Constructor Description WeightedStaticScheduling(int n, double rdd, double tf)
Generates random single machine scheduling problem instances.WeightedStaticScheduling(int n, double rdd, double tf, long seed)
Generates random single machine scheduling problem instances.WeightedStaticScheduling(String filename, int n, int instanceNumber)
Constructs a single machine scheduling problem instance by parsing an instance data file that follows the format specified in the ORLibrary of J.E.

Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int[]
getCompletionTimes(Permutation schedule)
Computes the completion times of all of the jobs if they were scheduled in the order defined by the specified Permutation.int
getDueDate(int j)
Gets the due date of a job, for scheduling problems that have due dates.int
getProcessingTime(int j)
Gets the processing time of a job, which is the amount of time required by the machine to process the job.int
getWeight(int j)
Gets the weight of a job, for weighted scheduling problems, where a job's weight indicates its importance or priority (higher weight implies higher priority).boolean
hasDueDates()
Checks whether this single machine scheduling instance has due dates.boolean
hasWeights()
Checks whether this single machine scheduling instance has weights.int
numberOfJobs()
Gets the number of jobs of this scheduling problem instance.void
toFile(String filename)
Outputs a description of the instance data in the format described by the ORLibrary of J.E.
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.cicirello.search.problems.scheduling.SingleMachineSchedulingProblemData
getEarlyWeight, getReleaseDate, getSetupTime, getSetupTime, hasEarlyWeights, hasReleaseDates, hasSetupTimes




Field Detail

MIN_PROCESS_TIME
public static final int MIN_PROCESS_TIME
Defines the minimum process times. Process times are generated uniformly at random from the interval: [MIN_PROCESS_TIME, MAX_PROCESS_TIME]. See Also:
 Constant Field Values

MAX_PROCESS_TIME
public static final int MAX_PROCESS_TIME
Defines the maximum process times. Process times are generated uniformly at random from the interval: [MIN_PROCESS_TIME, MAX_PROCESS_TIME]. See Also:
 Constant Field Values

MIN_WEIGHT
public static final int MIN_WEIGHT
Defines the minimum weight. Weights are generated uniformly at random from the interval: [MIN_WEIGHT, MAX_WEIGHT]. See Also:
 Constant Field Values

MAX_WEIGHT
public static final int MAX_WEIGHT
Defines the maximum weight. Weights are generated uniformly at random from the interval: [MIN_WEIGHT, MAX_WEIGHT]. See Also:
 Constant Field Values


Constructor Detail

WeightedStaticScheduling
public WeightedStaticScheduling(int n, double rdd, double tf, long seed)
Generates random single machine scheduling problem instances. Parameters:
n
 The number of jobs in the instance, must be positive.rdd
 The relative range of duedates. See the links in the class comments for an explanation of this parameter. Must be in the interval (0.0, 1.0].tf
 The tardiness factor. See the links in the class comments for an explanation of this parameter. Must be in the interval [0.0, 1.0].seed
 A seed for the random number generator, to enable easily generating the same problem instance. If all parameters, including the seed are the same, then the same instance will be generated. Throws:
IllegalArgumentException
 if n is not positive, or rdd ≤ 0 or rdd > 1 or tf < 0 or tf > 0.

WeightedStaticScheduling
public WeightedStaticScheduling(int n, double rdd, double tf)
Generates random single machine scheduling problem instances. Parameters:
n
 The number of jobs in the instance, must be positive.rdd
 The relative range of duedates. See the links in the class comments for an explanation of this parameter. Must be in the interval (0.0, 1.0].tf
 The tardiness factor. See the links in the class comments for an explanation of this parameter. Must be in the interval [0.0, 1.0]. Throws:
IllegalArgumentException
 if n is not positive, or rdd ≤ 0 or rdd > 1 or tf < 0 or tf > 0.

WeightedStaticScheduling
public WeightedStaticScheduling(String filename, int n, int instanceNumber) throws FileNotFoundException
Constructs a single machine scheduling problem instance by parsing an instance data file that follows the format specified in the ORLibrary of J.E. Beasley. The description, along with a set of benchmark instances, is mirrored in the following GitHub repository: https://github.com/cicirello/schedulingbenchmarks
The format from the benchmark library is a bit unusual. Each file contains many instances. There is no labeling info, so you need to know the number of jobs, n, contained in the file. The first instance is listed first with n process times, followed by n weights, followed by n duedates. This is then followed by second instance (n process times, n weights, and then n duedates), etc, with no instance separators.
 Parameters:
filename
 The name of the file containing the instances, with path.n
 The number of jobs in one instance. Behavior is undefined if n is inconsistent with the actual number of jobs of the instances contained in the file.instanceNumber
 The number of the instance to parse, where the first instance is instance 0. Behavior is undefined if instanceNumber is too high. Throws:
FileNotFoundException
 if the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading


Method Detail

getCompletionTimes
public int[] getCompletionTimes(Permutation schedule)
Description copied from interface:SingleMachineSchedulingProblemData
Computes the completion times of all of the jobs if they were scheduled in the order defined by the specified Permutation. The completion times are computed according to the processing times of the jobs, as well as setup times and ready times if the problem has these. Specified by:
getCompletionTimes
in interfaceSingleMachineSchedulingProblemData
 Parameters:
schedule
 A schedule (i.e., sequence of jobs on the machine). Returns:
 An array of completion times. Let C be the array of completion times.
C.length must equal schedule.length(). Additionally, C[j] must be the completion
time of job j (and not the completion time of the job
in position j of the Permutation). That is, the indexes into C correspond to the
parameter j of the
SingleMachineSchedulingProblemData.getProcessingTime(int)
method, and other related methods of this interface.

numberOfJobs
public int numberOfJobs()
Description copied from interface:SingleMachineSchedulingProblemData
Gets the number of jobs of this scheduling problem instance. Specified by:
numberOfJobs
in interfaceSingleMachineSchedulingProblemData
 Returns:
 the number of jobs

getProcessingTime
public int getProcessingTime(int j)
Description copied from interface:SingleMachineSchedulingProblemData
Gets the processing time of a job, which is the amount of time required by the machine to process the job. Specified by:
getProcessingTime
in interfaceSingleMachineSchedulingProblemData
 Parameters:
j
 The index of the job, which must be in the interval: [0, numberOfJobs()). Returns:
 the processing time of job j.

getDueDate
public int getDueDate(int j)
Description copied from interface:SingleMachineSchedulingProblemData
Gets the due date of a job, for scheduling problems that have due dates. The meaning of a due date, and its effect on the optimization cost function, may vary by problem. See the documentation of the specific scheduling problem's cost function for details. . Specified by:
getDueDate
in interfaceSingleMachineSchedulingProblemData
 Parameters:
j
 The index of the job, which must be in the interval: [0, numberOfJobs()). Returns:
 the due date of job j.

hasDueDates
public boolean hasDueDates()
Description copied from interface:SingleMachineSchedulingProblemData
Checks whether this single machine scheduling instance has due dates. Specified by:
hasDueDates
in interfaceSingleMachineSchedulingProblemData
 Returns:
 true iff due dates are present.

getWeight
public int getWeight(int j)
Description copied from interface:SingleMachineSchedulingProblemData
Gets the weight of a job, for weighted scheduling problems, where a job's weight indicates its importance or priority (higher weight implies higher priority). Many common scheduling problem cost functions use weights (e.g., weighted tardiness, weighted lateness, etc). The default implementation simply returns 1, which is appropriate for problems without weights (i.e., the unweighted variation of most scheduling cost functions is equivalent to the weighted version if all weights are 1). You can use theSingleMachineSchedulingProblemData.hasWeights()
method to check whether weights are present. Specified by:
getWeight
in interfaceSingleMachineSchedulingProblemData
 Parameters:
j
 The index of the job, which must be in the interval: [0, numberOfJobs()). Returns:
 the weight of job j.

hasWeights
public boolean hasWeights()
Description copied from interface:SingleMachineSchedulingProblemData
Checks whether this single machine scheduling instance has weights. Specified by:
hasWeights
in interfaceSingleMachineSchedulingProblemData
 Returns:
 true iff weights are present.

toFile
public void toFile(String filename) throws FileNotFoundException
Outputs a description of the instance data in the format described by the ORLibrary of J.E. Beasley. The description, along with a set of benchmark instances, is mirrored in the following GitHub repository: https://github.com/cicirello/schedulingbenchmarks
The only different with that format is that this stores only the one instance in the file. But for consistency with the original format, you do need to know the number of jobs for the instance (or you can determine this by counting number of integers in the file and dividing by 3.
 Parameters:
filename
 The name of a file for the output. Throws:
FileNotFoundException
 If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

