ExtendingScalaSciClasses

Introduction

ScalaSci source code is open source. Therefore, it is easy to extend ScalaSci classes in applications. We provide some examples.

Extending the Vector class

We illustrate how we can extend the scalaSci.Vec class and to provide for the new VecExt class, a map2 method that applies two times the given function to the vector elements.

class VecExt(n: Int) extends scalaSci.Vec(n)  {

// an auxiliary constructor that copies the contents of 
// the parameter v to the newly created VecExt
    def this(v: scalaSci.Vec) {
        this(v.length)
        for (k<-0 until v.length)
         this(k) = v(k)
        }


  // apply the function f to all the elements of the VecExt and return the results with a new Vec
 def  map2( f: (Double => Double)): Vec = {
   var len = this.length
   var vres = new Vec(len)

    for (r<-0 until len)
       vres(r) = f(f(this(r)) )

   vres
 }

 }

 // create a scalaSci.Vec  
 var v = sin(0.12*inc(0, 0.01, 10))

 // create an extended Vector
 var mv = new VecExt(v)

  // define a function 
 def  mf(x: Double) = { x*sin(8.9*x) }

// map it two times to our extended Vec class, using map2
 var m2v = mv map2 mf

// map the function two times again, but this time by using the function map
 var mv1mv1 = mv map mf map mf

// plot the results and the difference, to verify that map2 performs a map two times
 figure(1)
 subplot(3,1,1); plot(m2v, "result of map2")
 subplot(3,1,2); plot(mv1mv1, "result of map(map())")
 subplot(3,1,3); plot(m2v-mv1mv1, "difference")