My second site!!!

And this is my second site created with appengine: http://javarubyscala.appspot.com/view/StartPage

My first Google App Engine test !!!

This is the link http://0052631578947368421.appspot.com !!! a wiki-like site ( learned in a codelab of GooogleDeveloperDay ) with login!!!

Info about appengine are here:http://code.google.com/appengine/ .

Basically you can create ( in Python ) and deploy a webapp .

More info soon... 

Mandelbrot in Scala

I'm also working on a more complex mandelbrot set program in Scala.
Soon i'll post the source code.
This is the output:

Esoteric ruby Mandelbrot

Inspired from this article i've decided to
play with code in order to create my version of Madelbrot set program in ruby.
This is the code:

( not true, the code is here because the blogger editor didn't work fine when a code contain <
or > )


The code is intentionally obscure.

Is possible to decide: position, zoom factor, number of iterations, and number of lines.
The output should be like this:

Vedic Math first lesson

the Sutra says: "By one more than the previous one".
With this sutra you can calculate mentally this fraction:





easy, isn't it?
In the next few days i'll give the explanation of this method.

Code reduction ( obfuscation in ruby code )

This ruby code is equivalent to the code in previous post

N = 13; k = N-1; r = (1..k).to_a ; e = [r.first, r.last];
r.each{a print(r.map{b e.include?(b*a%N)?"1 ":" "},"\n")}

My first Ruby program!

This is my first Ruby program!

N = 13
def un( el, en )
  [1, en-1].include?(el%en)?re=1:re=" "; return re
end

(N-1).times do a
  (1...N-1).to_a.each{b print un((b+1)*(a+1),N), " "}
  print "\n"
end

A little obscure, isn't it?
The output is ( as desired ):

1                     1
          1 1    
      1         1
    1             1
        1     1  
  1                 1
  1                 1
        1     1  
    1             1
      1         1
          1 1    
1                     1

The same program in Scala can be written in this way:

object something {
  val un = ( el:Double, en:Double ) =>
    if( Array(1,en-1).contains( el%en) ) "1 " else "  "
                                  
  def main(args : Array[String]) : Unit = {
    val N = 23
    for(i <- 1 to N-1){ new Array(N-1)
     .indices.foreach(el => print( un((el+1)*(i),N) ))
      println()
    }
  }
}

and the output with N=23 is:
1                                         1
                    1 1              
              1             1        
          1                     1    
                1         1          
      1                             1
                  1     1            
    1                                 1
        1                         1  
            1                 1      
  1                                     1
  1                                     1
            1                 1      
        1                         1  
    1                                 1
                  1     1            
      1                             1
                1         1          
          1                     1    
              1             1        
                    1 1              
1                                         1

"Eyes follow mouse" in js

here is my interpretation of "eyes follow mouse" in javascript.
Nothing special but works fine.

an important function in this js is this one:

function objMove( obj, xPos, yPos ){
    obj.style.left = xPos + "px";
    obj.style.top =  yPos + "px";
}

is a function that move an object of the page.
the important thing is that works with ie, opera and firefox
an example of this eyes follow mouse at work.

Missing number

the result has 8 digits and the missing number is ... 8
soon i'll post some of Vedic maths

xml viewer in Scala

This is a snapshot of a program thought to show an xml
graphically

The xml source for this tree is here
The idea is to create a graphical editor for xml and processDefiniton
of Jbpm.

Soon I'll post some code ...

Haar wavelet transform in Scala

This is my first try to write a wavelet(ondine in Italian) transform in Scala.
Naturally i've choose Haar wavelet transform, the simplest!
This is the core of the transformation:

def waveletCalc( values: List[Double] ):List[List[Double]]=
 haarCalc( values , List( ) ).reverse

def haarCalc( vals: List[Double], cc: List[List[Double]] )
             :List[List[Double]] =
  vals.length / 2 match {
    case 1 => cc ::: List(  List((vals(0) - vals(1) ) / 2 ) ,
        List(( vals(0) + vals(1) ) / 2 ))
    case _ => haarCalc( vals.indices.dropRight(vals.length/2)
               .map(_*2).map(el=>(vals(el) + vals(el+1))/2),
                 cc ::: List( vals.indices.dropRight(
                  vals.length/2).map(2*_).map(el=>
                   (vals (el) - vals(el + 1))/2)))
}      

The algorithm is recursive and returns as a result a list of lists.
This arrangement is the most convenient since a base of wavelets has two indexes.
Soon i'll try to post the complete class with the inverse transform and a brief
description on this particular wavelets transform.
I strongly recommend to copy and paste the code in an editor to read it better...
you can find a more complete code here

Algebraic group

Today I started to write a class in Scala to represent a group (in the mathematical sense).
To test closure, i.e.:







the code I wrote is:

def closure( ): Boolean =
    elements.forall(
        el => elements.forall(
             el2 => elements.exists(
                   el2.*(el, this).name == _.name ) ) )

'elements' is the list of all group elements and and each element has a different 'name'.
The following piece of code is the product of two elements.

  el2.*(el, this)

the * operator is defined as follows:

 def *(  b : groupElement  ,group: genericGroup ) : groupElement

the code is not optimized, but it is amazing how, in this language,
we can write a test like this in a way so simple!

this is only a snippet of the entire code...

I hope to post the complete code soon

a Snapshot of my new Jung-Scala project

This is a snapshot from my first try to use

Jung (Java Universal Network/Graph Framework)

in a Scala project

Fast Fourier transform

Fast Fourier transform in Scala

http://sites.google.com/site/snakelemma/snippets/fftShort.scala?attredirects=0

Complx.scala

simple Complex number class in Scala programming language

http://sites.google.com/site/snakelemma/snippets/complx.scala?attredirects=0

little elliptic cryptography document

http://sites.google.com/site/snakelemma/documents/seminario-ecc.pdf?attredirects=0

little scala snippet

def showRow(arra: Array[int], molt: int, mod: int ,unitari : boolean ):Array[int] = {
    val a2 = arra.map( s => ( s * molt ) % mod )

    if ( unitari )
        println ( a2.map( s => if ( s == 1 s == ( mod -1 ) ) 1 else 0 ).toString )
    else
        println( a2.toString )
    a2
}

def shoMatr( mod: int , unitari : boolean ) {

    println( if ( unitari ) "elementi unitari" else "tabella moltiplicativa" )

    val array = new Array[int]( mod - 1 ).indices.map( s => s + 1 )

    array.foreach( p => showRow( array , ( array indexOf p ) + 1 , mod , unitari ) )

}