Django Python Module on OS X Lion 10.7.2

As python programmer, I wish I could build a web using it too. I used to use CMS based portal, but eventually I want python thing in my site. Fortunately, it can be done, using Django.

According it site, Django (https://www.djangoproject.com/) is a high-level Python Web framework that encourages rapid development and clean, pragmatic design.

Developed by a fast-moving online-news operation, Django was designed to handle two challenges: the intensive deadlines of a newsroom and the stringent requirements of the experienced Web developers who wrote it. It lets you build high-performing, elegant Web applications quickly.

So I finally give it a try, it isn't hurt anyway, :). Installing Django in my Python 2.7 on my 13' Macbook Pro with OS X Lion 10.7.2 is fairly easy, using pip from pypi (pypi.python.org/). All I have to do is typing in terminal: pip install django. Of course, we need pip to be installed first.

Nugrohos-MacBook-Pro:python nugroho$ pip django
Usage: pip COMMAND [OPTIONS]


pip: error: No command by the name pip django
(maybe you meant "pip install django")
Nugrohos-MacBook-Pro:python nugroho$ pip install django
Downloading/unpacking django
Downloading Django-1.3.1.tar.gz (6.5Mb): 6.5Mb downloaded
Running setup.py egg_info for package django

Installing collected packages: django
Running setup.py install for django
changing mode of build/scripts-2.7/django-admin.py from 644 to 755

changing mode of /Library/Frameworks/Python.framework/Versions/2.7/bin/django-admin.py to 755
Successfully installed django
Cleaning up...
Nugrohos-MacBook-Pro:python nugroho$python
Python 2.7.2 (v2.7.2:8527427914a2, Jun 11 2011, 15:22:34)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import django
>>> print django.get_version()
1.3.1
>>> exit()
Nugrohos-MacBook-Pro:python nugroho$

That's it.

Double Tap Dragging on Lion

I wrote about missing single-tap-hold on Lion to dragging. However, after googling around, I found that it's still has capability to do it, just you will find it at the most unpredictable place in System Preferences

To enable one finger drag by double-tap-hold, go to System Preferences, click on Universal Access, and then the Mouse & Trackpad tab. Click on the “Trackpad Options…” at the bottom section of window. Enable dragging option; we can select the desired dragging behaviour from the drop down list. I wonder why this preference is here, not on trackpad section instead.

From Blogsy Photos

Lion have more Finger Gesture than Snow Leopard

Migrating from Snow Leopard to Lion is confusing and annoying but fun experience. One feature of Lion that I noticed very much is new finger gesture as it's a whole different experience than Snow Leopard.



I noticed first bad feeling when I browsing through Safari and can't double-tap-hold todragging a text to highlight it. I think, oh my God, my trackpad is broken. Calming down, go to preferences panel. I can't find double tap option, hm. Drag n Drop now can be done by three finger, uh. Highlighting text using three finger seems wrong to me. So, no double-tap-hold. (edit: there is double-tap-hold )

Two finger gesture to scroll and zoom is intact. Hm, not really. Scroll direction now has default option to 'natural', iPad like scroll.

No Exposé or Space, just Mission Control. Mission Control contain apps on current active desktop, just like Exposé, and all full screen apps, including other desktop.

Sweeping down four finger now show windows from same apps while sweeping up bring us to Mission Control. Sweeping left or right will bring us to next full screen apps (Desktop's treated as fullscreen apps).

A new gesture is pinching with four finger; pinching down will bring up Launchpad, an apps list just like iOS. A reverse pinching, spread (not sure what it's named), will push all windows to side to show Desktop.

I'm a bit missing the time when I could switch apps by sweeping down my four finger. Moving apps through spaces has gone too, but I guess it's a sacrifice to be able jump too next step.

Operasi Vektor di Python

Di python terdapat operasi dot dan cross untuk array. Namun ketika saya terapkan, ternyata operasi tersebut bukan merupakan operasi vektor melainkan operasi untuk matrik. Mungkin saya yang kurang mempelajari lebih mendalam atau mungkin memang demikian sifat operasi tersebut, akhirnya saya mendefinisikan sendiri operasi dot dan cross untuk vektor menggunakan def (semacam implementasi python untuk function atau procedure).



Berikut adalah contoh perbandingan operasi vektor di python. Kode yang atas adalah operasi bawaan dari Python sedangkan yang bawah adalah operasi dot dan cross dengan definisi yang baru

from numpy import *
from numpy.linalg import *
a=array((4,5,7),float)
b=array((2,3,4),float)
c=array((1,2,3),float)
print 'axb',a*b
print 'bxa',b*a
print 'dot(a,b)',dot(a,b)
print 'c.(axb)',dot(c,(a*b))
print '(bxa).c',dot((b*a),c)
print 'ax(bxc)',a*(b*c)
print '(axb)xc',(a*b)*c
print '(a.c)b-(a.b)c',(dot(a,c)*b)-(dot(a,b)*c)
print 'a=',a,'2a=',2*a
d=7*a+11*b
print 'd',d

def cross(v, w):
    x = v[1]*w[2] - v[2]*w[1]
    y = v[2]*w[0] - v[0]*w[2]
    z = v[0]*w[1] - v[1]*w[0]
    return (x, y, z)

def dott(v, w):
    return v[0]*w[0] + v[1]*w[1] + v[2]*w[2]

print 'axb',cross(a,b)
print 'bxa',cross(b,a)
print 'dot(a,b)',dott(a,b)
print 'c.(axb)',dott(c,cross(a,b))
print '(bxa).c',dott(cross(b,a),c)
print 'ax(bxc)',cross(a,cross(b,c))
print '(axb)xc',cross(cross(a,b),c)
print '(a.c)b-(a.b)c',((dott(a,c)*b)-(dot(a,b)*c))
print 'a=',a,'2a=',2*a
print '(axb)x(cxb)=b[b.(cxa)]'
print cross(cross(a,b),cross(c,b))
print b*(dott(b,cross(c,a)))

Operasi Matrik di Python

Python dapat melakukan operasi matrik semacam invers, normalisasi, determinan, mencari nilai eigen, trace, bahkan eksponen matrik.



Untuk dapat menggunakan operasi matrik di Python, kita membutuhkan modul numpy.

Berikut adalah contoh kode operasi matrik di python.

from numpy import *
from numpy.linalg import *
a=array(((1,2),(3,3)),float)
b=inv(a)
c=dot(a,b)
d=norm(a)
e=eig(a)
f=det(a)
g=trace(a)
h=exp(a)
i=log(a)
print 'matrik A ='
print a
print 'matrik invers A = B ='
print b
print 'AB ='
print c
print 'norm A ='
print d
print 'eigen A ='
print e
print 'det A ='
print f
print 'trace A ='
print g
print 'exp A ='
print h
print 'log A ='
print i
z=array(((0.0,0.0+1.j),(0.0-1.j,0)),complex)

  
    

Perhatikan bahwa python juga mendukung bilangan imajiner sehingga dapat digunakan untuk menghitung matrik kompleks

Menggambar Grafik di Python dengan Matplotlib

Ada beberapa modul di python untuk menggambar grafik, semacam graphy, pycairochart, matplotlib dll. Berikut adalah contoh plot grafik dari y=sin(x) dengan range x dari -10 s.d 10 dengan resolusi 0.1 satuan. Resolusi di sini adalah langkah dari -10 ke 10, jadi kita akan mem-plot sin(-10), sin(-9,9), sin(-9.8), ...

from matplotlib.pyplot import *
from visual import *
x=[]
x=arange(-10.,10.,0.1)
grid(True)
xlabel('Sumbu x')
ylabel('Sumbu y')
title('Jejak ')
plot(x,sin(x),'b-')
batas=10
ylim(-2,2)
xlim(-batas,batas)
show()

The Journey of Installing Matplotlib Python Module on OS X Lion

I need matplotlib to plot my python output when I am running my output function generator python code.

This post is a log of what I did to being able to install matplotlib 1.1.0 on python 2.7.2 on my Mac OS X Lion 10.7.2. Yet, it's unfinished job.

First, googling for matplotlib, sourceforge is official home fon it, but it's very slow, I coudn't even open download page with my sluggish connection. So, I searching other source.

Got it from kambing.ui.ac.id, it has pypi repositories, but when it opened, there is no package, just blank folder.

After further googling, I finally found http://pypi.python.org, pypi stand for python package index.

To be able to use pypi package, we have to install pip first, but before that install distribute using this command

curl http://python-distribute.org/distribute_setup.py | python
curl https://raw.github.com/pypa/pip/master/contrib/get-pip.py | python

and then install matplotlib using pip, there is download activity, but got error at the end; must install numpy first, but it got error too as I didn't have GCC on my lion yet, aaarrrgghh... So, the hell of dependencies is begin...

So here I am, searching for 'light' GCC for my lion. I know I should install XCode 4 from Apple , it's free anyway, but I must face the fact that it's including 4.5GB download job, such a tedious job and wasting time; I just want to install 13 MB matplotlib.

I wish I can type the code below

pip install numpy
pip install matplotlib

(pray)