WekaSharp: An F# Wrapper for Weka

An F# Wrapper for Weka.

Sample Usage

WekaSharp: Tutorial for running Weka in F#/.Net

WekaSharp: An F# wrapper for Weka

(* playing decision trees on Iris dataset *)

// load the dataset
let iris = 
    @"C:\Program Files\Weka-3.6\data\iris.arff"
    |> Dataset.readArff
    |> Dataset.setClassIndexWithLastAttribute 

// describe 3 kinds of classification tasks
let j48Tt = TrainTest(iris, iris, ClassifierType.J48, Parameter.J48.DefaultPara)
let j48Cv = CrossValidation(5, iris, ClassifierType.J48, Parameter.J48.DefaultPara)
let j48Rs = RandomSplit(0.7, iris, ClassifierType.J48, Parameter.J48.DefaultPara)

// perform the task and get result
let ttAccuracy = j48Tt |> Eval.evalClassify |> Eval.getAccuracy
let cvAccuracy = j48Cv |> Eval.evalClassify |> Eval.getAccuracy
let rsAccuracy = j48Rs |> Eval.evalClassify |> Eval.getAccuracy

(* test cluster algorithms *)

 let irisNolabel = 
    @"C:\Program Files\Weka-3.6\data\iris.arff"
    |> Dataset.readArffLastAttributeAsLabel
    |> Dataset.removeClassAttribute

let irisLabeled = 
    @"C:\Program Files\Weka-3.6\data\iris.arff"
    |> Dataset.readArffLastAttributeAsLabel

let kmeansTask = ClusterWithLabel(irisLabeled, ClustererType.KMeans, Parameter.KMeans.MakePara(K=3))
let emTask = ClusterWithLabel(irisLabeled, ClustererType.EM, Parameter.EM.MakePara(K=3))
let dbscanTask = ClusterWithLabel(irisLabeled, ClustererType.DBScan, Parameter.DBScan.DefaultPara)


let kmeansResult = Eval.evalClustering kmeansTask |> Eval.getClusterSummary
let emResult = Eval.evalClustering emTask |> Eval.getClusterSummary
let dbscanResult = Eval.evalClustering dbscanTask |> Eval.getClusterSummary

(* bulk & parallel processing example *)

// load the data set
let sonar = 
    @"D:\temp\datasets-UCI\UCI\sonar.arff"
    |> Dataset.readArff
    |> Dataset.setClassIndexWithLastAttribute

// set different parameters 
let Cs = [0.01; 0.1; 1.; 10.; 50.; 100.; 500.; 1000.; 2000.; 5000. ]

// make the tasks with the parameter set
let tasks = 
    Cs
    |> List.map (fun c -> Parameter.SVM.MakePara(C = c))
    |> List.map (fun p -> CrossValidation(3, sonar, ClassifierType.SVM, p))
    
Profile.tic()
// the accuracy result
let results = 
    tasks
    |> Eval.evalBulkClassify
    |> List.map Eval.getAccuracy
Profile.toc("sequential time: ")


Profile.tic()
let resultsParallel = 
    tasks
    |> Eval.evalBulkClassifyParallel
    |> List.map Eval.getAccuracy
Profile.toc("parallel (PSeq) time: ")

// sequential time: : 9767.804800 ms
// parallel (PSeq) time: : 6154.715500 ms

(* do the plot *)

 lc.column(y = results, xname = "differnet C", yname = "Accuracy", title = "SVM on iris",
    isValueShownAsLabel = true ) |> display

(* create dataset from F# arrays *)

// make the data array
let data = [| 0.; 0.; 
              1.; 1.; 
              0.; 1.; 
              1.; 0.; |]
let xorArray = Array2D.init 4 2 (fun i j -> data.[i*2 + j])

// make weka dataset from array
let xor0 = Dataset.from2DArray xorArray false

// add labels 
let xor = xor0 |> Dataset.addClassLabels ["T"; "T"; "F"; "F"]

// make a svm classifier

let rbfTask = TrainTest(xor, xor, ClassifierType.SVM, Parameter.SVM.DefaultPara)
let linearTask = TrainTest(xor, xor, ClassifierType.SVM, Parameter.SVM.MakePara(kernelType = Parameter.SVMKernelType.LinearKernel) )

// rbf svm gets 100% accuracy
let rbfAccuracy = rbfTask |> Eval.evalClassify |> Eval.getAccuracy
// linear svm does not work on XOR data set
let linearAccuracy = linearTask |> Eval.evalClassify |> Eval.getAccuracy

More  Datasets

Sample ARFF data files are available at http://www.cs.waikato.ac.nz/ml/weka/index_datasets.html.