Belajar.

Dulu belajar berbicara.

Sekarang perlu untuk belajar diam.

(The Tales of Tatonka)

Pasir

Berapa nikmat yang diberikan kepadaku?

Ngawur,

kurang kerjaan.

Sana, mending hitung butiran pasir di pantai saja sana,

tu lebih sedikit, lebih gampang.

(terinspirasi status mbakYu)

Lagrange Interpolation using Python

 Here it is. We could set the order of interpolation by changing the value of k

from pylab import *
from random import uniform
k = 11

def l(t):
    l = []
    for i in arange (len(t)):
        l.append(0.)
        for j in arange(k+1):
            lag = 1.
            for m in arange(k+1):
                if m!=j:
                    lag = lag * (t[i]-x[m])/(x[j]-x[m])
            l[i] = l[i]+y[j]*lag
            

    return l

def f(x):
    f = []
    for i in arange (len(x)):
        f.append(0.)
        f[i] = x[i]+uniform(-10,10)
    return f

x = arange(0.0, 2.0, 0.1)
t = arange(0.,2.,0.001)
y = f(x)
z = l(t)

plot(x,y)
plot(t,z)
xlabel('x')
ylabel('y')
title('interpolasi')
grid(True)
axis([0,2,-111,111])
#savefig("test.png")
show()

.

Walking Sine on Visual Python GDisplay

 Look, the wrong way often provide a beautiful result. Yeah, it's not what the program should be, but still I like it, :)

from __future__ import division, print_function
from visual import *
from visual.graph import *

def f(x):
    f = sin(pi*x+p)
    return f
def g(x):
    g = cos(pi*x)
    return g

graph1 = gdisplay(x=0, y=0, width=600, height=400, 
          title='A vs. t', xtitle='t', ytitle='A', 
          foreground=color.black, background=color.white)
p = 0.
f1 = gcurve(color=color.blue)
f2 = gcurve(color=color.red)

t = arange(-2.,2.,0.01)
s = g(t)
while True:
    rate(100)
    f1.gcurve.pos=[]  #delete this and look at the effect :)
    f2.gcurve.pos=[]
    u = f(t)
    for i in arange(len(s)):
        f2.plot(pos=((i-len(s)/2.)*.01,s[i]))
        f1.plot(pos=((i-len(s)/2.)*.01,u[i]))
    p = p + 0.01
    if p >100:
        p = 0

Fourier Transform using Delphi

 It's not Discrete Fourier Transform.

 Instead, I use continue definition (using Integral, not Sum) to compute the transformation. I know, it's weird, but it's worth a try, :)

 What I did is transform signal with 3 frequency, remove the two frequency and trasform back to time-signal.

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls;

type
  TForm1 = class(TForm)
    Image1: TImage;
    Timer1: TTimer;
    Memo1: TMemo;
    Image2: TImage;
    Image3: TImage;
    Image4: TImage;
    procedure proses;
    procedure gambarFungsi;
    procedure gambarSumbu;
    procedure gambarTransformasi;
    procedure olahTransformasi;
    procedure gambarOlahTransformasi;
    procedure transformasiBalik;
    procedure gambarTransformasibalik;
    function f(x:real):real;
    procedure Timer1Timer(Sender: TObject);
  private
  public
  end;

const
  a=200;
  b=150;

var
  Form1: TForm1;
  x0,y0,xm,ym:integer;
  s,ss:array[-a..a]of real;
  ft:array[-b..b]of real;
implementation
{$R *.dfm}
function tform1.f(x:real):real;
begin
  f:=cos(PI*x)+cos(2*PI*x)+cos(4*PI*x);
end;
procedure tform1.transformasiBalik;
var i,j:integer;
t,w,dt:real;
begin{}
  dt:=0.1;
  for i:=-a to a do begin
    w:=i/10;
    ss[i]:=0;
    for j:=-b to b do begin
      t:=j/10;
      ss[i]:=ss[i]+ft[j]*cos(w*t)*dt
    end;
  end;
  gambarTransformasiBalik;
end;

procedure tform1.olahTransformasi;
var i:integer;
begin
  for i:=-b to b do begin
    if abs(i)>50 then ft[i]:=0;
  end;
  gambarOlahTransformasi;
end;

procedure tform1.proses;
var i,j:integer;
t,w,dt:real;
begin
  form1.Caption:='transformasi';
  gambarSumbu;
  {transformasi}
  dt:=0.1;
  for i:=-a to a do begin
    s[i]:=f(i/30);
  end;
  for i:=-b to b do begin
    w:=i/10;
    ft[i]:=0;
    for j:=-a to a do begin
      t:=j/10;
      ft[i]:=ft[i]+f(t)*cos(w*t)*dt
    end;
  end;
  gambarFungsi;
  gambarTransformasi;
  olahTransformasi;
  transformasiBalik;
end;

procedure tform1.gambarFungsi;
var i,xo,yo,xt,yt:integer;
begin
  xo:=-a; yo:=0;
  for i:=-a to a do begin
    xt:=i;
    yt:=round(10*s[i]);
    with image1.Canvas do begin
      moveto(x0+xo,y0-yo);lineto(x0+xt,y0-yt);
    end;
    xo:=xt;
    yo:=yt;
  end;
end;

procedure tform1.gambarTransformasibalik;
var i,xo,yo,xt,yt:integer;
begin
  xo:=-a; yo:=0;
  for i:=-a to a do begin
    xt:=i;
    yt:=round(10*ss[i]);
    with image4.Canvas do begin
      moveto(x0+xo,y0-yo);lineto(x0+xt,y0-yt);
    end;
    xo:=xt;
    yo:=yt;
  end;
end;

procedure tform1.gambarOlahTransformasi;
var i,xo,yo,xt,yt:integer;
begin
{}
  xo:=-b; yo:=0;
  for i:=-b to b do begin
    xt:=i;
    yt:=round(10*ft[i]);
    with image3.Canvas do begin
      moveto(x0+xo,y0-yo);lineto(x0+xt,y0-yt);
    end;
    xo:=xt;
    yo:=yt;
  end;
end;

procedure tform1.gambarTransformasi;
var i,xo,yo,xt,yt:integer;
begin
  xo:=-b;yo:=0;
  for i:=-b to b do begin
    xt:=i;
    yt:=round(10*ft[i]);
    with image2.Canvas do begin
      moveto(x0+xo,y0-yo);lineto(x0+xt,y0-yt);
    end;
    xo:=xt;
    yo:=yt;
  end;
end;

procedure tform1.gambarSumbu;
begin
  x0:=image1.Width div 2;
  y0:=image1.Height div 2;
  xm:=image1.Width;
  ym:=image1.Height;
  with image1.Canvas do begin
    moveto(0,y0);lineto(xm,y0);moveto(x0,0);lineto(x0,ym);
  end;
  with image2.Canvas do begin
    moveto(0,y0);lineto(xm,y0);moveto(x0,0);lineto(x0,ym);
  end;
  with image3.Canvas do begin
    moveto(0,y0);lineto(xm,y0);moveto(x0,0);lineto(x0,ym);
  end;
  with image4.Canvas do begin
    moveto(0,y0);lineto(xm,y0);moveto(x0,0);lineto(x0,ym);
  end;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  timer1.Enabled:=false;
  proses;
end;

end.

HFS+ (Journaled) Flash Drive on Ubuntu

 I have no problem mount it on Centos, read and write mode.

 But, on Ubuntu, it needs some works.

 Install hfsprogs

 

sudo apt-get install hfsprogs

 umount the drive if it's already meunted

sudo umount /dev/sdb2

create folder to mount the drive

mkdir flash

mount again

sudo mount -t hfsplus -o force,rw /dev/sdb2 flash

It works for me, but it need sudo privilege to write to it. Maybe because it's journaled and ubuntu didn't support journaled HFS+ filesystem.

At least it works, :)

#MelawanAsap

 Yang tak terlupa, saat ada acara pembacaan surat YaaSin di rumah, ikut tradisi setempat, saat bapak meninggal.

 Yeah, bapak meninggal, itu sulit dilupakan.

 Tapi beberapa minggu ini ada yang mengungkit-ungkit kenangan itu lagi, kebakaran di Sumatera dan Kalimantan.

 Bukan tentang bapak yang diungkit (mudah sekali mengingat kejadiaan itu), tetapi tentang asap.

 Apa yang terjadi saat pembacaan surat YaaSin? Tentu saja, membaca surat YaaSin bersama-sama, diawali surat-surat pendek untuk pemanasan, Yaasin, trus doa-doa yang dipimpin secara estafet oleh dua pemuka agama.

 Yang terungkit oleh kebakaran di SwarnaDwipa dan Borneo justru sebelum acara. Ketika tamu mulai datang dan menunggu yang lain. Harus menemui tamu itu jelas, dan kebanyakan mereka adalah perokok! Hm, mereka merokok sebelum mendoakan seseorang yang meninggal akibat rokok, ckckck.

 Ketika acara akan mulai, tamu sudah semakin banyak, delapan puluh lebih. Ruangan sudah penuh hingga meluber ke halaman. Juga asap rokoknya.

 Sehari, ..., OK

 Dua hari, OOOOK...

 Hari ketiga, KO..., ke bidan, kena radang tenggorokan parah, harus minum 7 jenis pil.


 (dan ada dua pil yang mempunyai kandungan sama, sehingga dosisnya tanpa sengaja dobel, efeknya ketiga terbangun jam tiga pagi mau pipis, gak bisa gerak, otot kaku njarem, seperti habis berlari sprint sepuluh kilo, atau habis nabrak sedan diam dengan naik sepeda 80km/jam [sudah pernah mengalami, :) ])

 That's it. Asap, cuma terpapar tiga hari, dan setiap hari hanya sekitar dua jam.

 Bayangkan saudara kita di Sumatera dan Kalimantan.  Mereka di Pulau Emas dan Borneo terpapar setiap saat selama berminggu-minggu. SwarnaDwipa sedang berduka.