Thread: Help in recoding more efficiently

Hi

I am very new to Java and need help in recoding my program
At the moment I have a patch of code which is performed every 6 hours
Part of this code needs only to be performed ONCE!
But I am having the greatest difficulty in separating the once-only portion out......
I have marked the once-only portion in red

This is the relevant portions of code.............
********************************************

// create an array of weka filters - select attributes to be unused - choices for each classifier
int[][] filtersArray = new int[][] {
{ 1, 3, 5, 6, 8, 10}, // KStar
{ 1, 3, 5, 6, 8, 10}, // J48
{ 1, 3, 5, 6, 7, 8, 10}, // JRip
{ 1, 3, 6, 7, 8, 9, 10}, // NaiveBayes
{ 1, 2, 3, 5, 6, 8, 10}, // LMT
{ 1, 3, 5, 6, 8, 11}, // KStar
{ 2, 4, 7, 9, 11} // LibSVM
};

// create an array of the number of the class attribute for each classifier prior to filtering
int[] classAttributeArray = new int[] {
12, 12, 12, 12, 12, 11, 11};

// create strings of weka options - choices for each classifier
String[][] optionsArray = new String[][] {
weka.core.Utils.splitOptions("-B 35 -M a"), // KStar
weka.core.Utils.splitOptions("-C 0.25 -M 2"), // J48
weka.core.Utils.splitOptions("--F 3 -N 2.0 -0 2 -S 1 -E"), // JRip
weka.core.Utils.splitOptions(""), // NaiveBayes
weka.core.Utils.splitOptions("-I -1 -M 15 -W 0.0 -A"), // LMT
weka.core.Utils.splitOptions("-B 35 -M a"), // KStar
weka.core.Utils.splitOptions("-S 3 -K 2 -D 3 -G 0.0 -R 0.0 -N 0.5 -M 40.0 -C 1.0 -E 0.0010 -P 0.1") // LibSVM
};

//************************************************** *****
private class WekaApp {

public BufferedReader readDataFile(String filename) {
BufferedReader inputReader = null;

return inputReader;
}

void doInit() throws Exception {

BufferedReader datafile = readDataFile("C:/Databases/us_copiosus");

InstanceQuery query = new InstanceQuery();
query.setQuery("SELECT * from USD_JPY");
Instances data = query.retrieveInstances();

// Split instances into training and testing (the split percentage is 97.56%)
double percent = 97.56;
int trainingSize = (int) Math.round(data.numInstances() * percent / 100);
int testingSize = data.numInstances() - trainingSize;
Instances training = new Instances(data, 0, trainingSize);
Instances testing = new Instances(data, trainingSize, testingSize);

// Choose a set of classifiers
Classifier[] models = new Classifier[] {
new KStar(),
new J48(),
new JRip(),
new NaiveBayes(),
new LMT(),
new KStar(),
new LibSVM()
};

Predicted_Trend = 0;

// Run for each classifier model
for(int j = 0; j < models.length; j++) {

training.setClassIndex(classAttributeArray[j]);
testing.setClassIndex(classAttributeArray[j]);

myConsole.getOut().println("ClassIndex: "+ training.classAttribute().name());


Remove filter = new Remove(); // First, we create the base object.
filter.setAttributeIndicesArray(filtersArray[j]); // Finally, we provide an array of integer indexes.

//build classifier - do this once only for each classifier

FilteredClassifier fc = new FilteredClassifier(); // Create a FilteredClassifier object
((OptionHandler)models[j]).setOptions(optionsArray[j]);

try{
myConsole.getOut().println("Options4: "+ Arrays.toString(((OptionHandler)models[j]).getOptions()));
}
catch(Exception e)
{
myConsole.getOut().println(e);
}

fc.setClassifier(models[j]);

fc.setFilter(filter);


fc.buildClassifier(training);

// test the model
Evaluation eval = new Evaluation(training);
eval.evaluateModel(fc, testing);

// print the results a la weka Explorer: etc
*****************************************

Any suggestions / help much appreciated

Bob M

Welcome! Please read this topic to learn how to post code in code or highlight tags and other useful info for newcomers. Unfortunately, doing it correctly will prevent one using colored code, but then you can comment the code you wish to highlight.

As for executing code at a timed interval, I recommend you look into using a Java util.Timer. You can find info on that and examples on how to use it in the Java Tutorials.

Originally Posted by GregBrannon

Welcome! Please read this topic to learn how to post code in code or highlight tags and other useful info for newcomers. Unfortunately, doing it correctly will prevent one using colored code, but then you can comment the code you wish to highlight.

As for executing code at a timed interval, I recommend you look into using a Java util.Timer. You can find info on that and examples on how to use it in the Java Tutorials.

Hi Greg

Executing code at a timed interval is NOT my problem............
I just wish to extract the highlighted code so that it runs once only

Thanks

Bob M

Originally Posted by Norm

Use a one time boolean:

  boolean oneTime = true;
   ...
  if(oneTime) {
     oneTime = false;
     // do the stuff here
  }  // end one time code

Hi Norm

That is exactly what I have already tried to do but I am having difficulty grasping how to refer to each of the seven classifiers outside the once-only part of code ???

Bob M

Originally Posted by Norm

Define the variables so that their scope covers all the places that the code needs access to them.

Could you elaborate on your statement with examples please

Bob M

Originally Posted by Norm

Do you understand what the "scope" of a variable's definition means? It has to do with the closest pair of {}s that surround it. A variable's definition is out of scope outside of the {}s that surround its definition.

I use definition the same as some use declaration. The following defines the variable x as an int:

int x;  //  define an int variable

A variable can be defined in one place and given a value in another. Local variables will need to be given a value when they are defined.

hi Norm

When I encapsulate the red code in a once-only loop I run into problems............

the very next line of code is fc.buildClassifier(training);

but the 'fc' no longer is in scope ???

Bob M

Originally Posted by Norm

Where is fc defined relative to where it is being used? Are those two source lines within the same {} pair?

Initially, the 'fc' forms part of the once-only code and so is encapsulated within this code
But I am using fc..... outside this {}

I therefore took the fc definition line out of the once-only code and put it just above the once-only code start

My code is now as follows:-

// Run for each classifier model
for(int j = 0; j < models.length; j++) {
 
training.setClassIndex(classAttributeArray[j]);
testing.setClassIndex(classAttributeArray[j]);
 
myConsole.getOut().println("ClassIndex: "+ training.classAttribute().name());
 
FilteredClassifier fc = new FilteredClassifier(); // Create a FilteredClassifier object
 
if (oneTime) {
 
oneTime = false;
Remove filter = new Remove(); // First, we create the base object.
filter.setAttributeIndicesArray(filtersArray[j]); // Finally, we provide an array of integer indexes.
 
//build classifier - do this once only for each classifier
 
((OptionHandler)models[j]).setOptions(optionsArray[j]);
 
try{
myConsole.getOut().println("Options4: "+ Arrays.toString(((OptionHandler)models[j]).getOptions()));
}
catch(Exception e)
{
myConsole.getOut().println(e);
}
 
fc.setClassifier(models[j]);
 
fc.setFilter(filter);
 
} // end of oneTime loop
 
fc.buildClassifier(training);
 
// test the model
Evaluation eval = new Evaluation(training);
eval.evaluateModel(fc, testing);
 
// print the results a la weka Explorer: etc

Originally Posted by Norm

Please edit your post and wrap your code with code tags:
[code=java]
YOUR CODE HERE
[/code]
to get highlighting and preserve formatting.


Does the program work like you want it to now?

In a word - No!

The first iteration (time interval) is perfect
Thereafter it is all wrong

p.s. normally I wouldn't worry about repeating code over and over but the classifier LibSVM has a 'bug' I think
On the first iteration the 'S' option is set to '3' as per my array
Thereafter the 'S' option is set to '0' even tho I am reading the same array details

Oh well

Bob M