## lunedì 3 novembre 2008

### My second site!!!

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

## mercoledì 22 ottobre 2008

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

## martedì 14 ottobre 2008

### 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

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:

## domenica 5 ottobre 2008

### 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.

## sabato 4 ottobre 2008

### 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")}

## venerdì 3 ottobre 2008

### My first Ruby program!

This is my first Ruby program!

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

## giovedì 2 ottobre 2008

### "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

## lunedì 29 settembre 2008

### 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 ...

## venerdì 26 settembre 2008

### 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

## mercoledì 24 settembre 2008

### 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

## lunedì 22 settembre 2008

### Fast Fourier transform

Fast Fourier transform in Scala

## sabato 13 settembre 2008

### Complx.scala

simple Complex number class in Scala programming language

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 ) )}