technical blog

math input test

2015-07-11T04:50:00.001-07:00

Einstein's most famous equation is $E=mc^2$.
Newton derived the equation [s=ut+\sfrac{1}{2}at^2]

2015-07-11T04:29:00.001-07:00

$\sum_i^2$

PyPI mirror error

2012-10-25T07:36:00.003-07:00

Copying /packages/source/Q/Quotient/Quotient-0.3.0.tar.gz
Traceback (most recent call last):
File "/usr/local/bin/pep381run", line 30, in <module>
state.synchronize()
File "/usr/local/lib/python2.7/dist-packages/pep381client/__init__.py", line 119, in synchronize
self._synchronize()
File "/usr/local/lib/python2.7/dist-packages/pep381client/__init__.py", line 159, in _synchronize
self.maybe_copy_file(project, file)
File "/usr/local/lib/python2.7/dist-packages/pep381client/__init__.py", line 247, in maybe_copy_file
data = r.read()
File "/usr/lib/python2.7/httplib.py", line 548, in read
s = self._safe_read(self.length)
File "/usr/lib/python2.7/httplib.py", line 647, in _safe_read
chunk = self.fp.read(min(amt, MAXAMOUNT))
File "/usr/lib/python2.7/socket.py", line 380, in read
data = self._sock.recv(left)
socket.error: [Errno 104] Connection reset by peer

latex bibtex installation and usage under ubuntu

2012-10-23T19:17:00.002-07:00

#install latex under ubuntu
sudo apt-get install texlive
sudo apt-get install texlive-ful
sudo apt-get install gedit-latex-plugin # need to activate the plugin in the gedit->edit->preferences->plugins

#other packages recommended

sudo apt-get install texlive-fonts-recommended latex-beamer texpower texlive-pictures texlive-latex-extra texpower-examples imagemagick

#using in the bash console
latex filename.tex
bibtex filename.aux
latex filename.tex
latex filename.tex

#view the file
xdvi filename
dvips filename # change into .ps file
gv filename.ps # view the .ps file with gv
ps2pdf filename.ps # change into .pdf file from .ps file

Reference:
http://linuxandfriends.com/2009/10/06/install-latex-in-ubuntu-linux/
https://help.ubuntu.com/community/LaTeX
http://www.ccrnp.ncifcrf.gov/~toms/latexforbeginners.html

ubuntu dpkg no lock and status file

2012-10-22T19:37:00.000-07:00

Problem:

Upgrade Ubuntu from 12.04 to 12.10 needs a long time, so I just keep the laptop to upgrade unplugged, when getting up, found the dpkg locked for the unusual shutdown, the stupid thing I did is:

Delete the lock, and the dpkg folder

The errors I got is:
1) Could not open lock file /var/lib/dpkg/lock - open (2: No such file or directory)
2) Unable to lock the administration directory (/var/lib/dpkg/), are you root?

Solution:

1) sudo mkdir /var/lib/dpkg/
error 1) and 2) would disappear, however when apt-get update, a new error comes out:

Could not open file /var/lib/dpkg/status - open (2: No such file or directory)

2) sudo cp /var/backups/dpkg.status.0 /var/lib/dpkg/status

Now it works fine.

Thanks the following references:

http://www.linuxquestions.org/questions/linux-software-2/e-unable-to-lock-the-administration-directory-var-lib-dpkg-are-you-root-886443/

http://ubuntuforums.org/showthread.php?t=2008867

bible for phd

2012-08-27T09:15:00.005-07:00

Since the master period, I am often excited when finding some academic advices, online academic tutorials and public courses online, however, just after a while, I will lost them, even I often bookmarks them. This needs becoming much more strong when stepping into the phd candidates group. So this ideas comes out, why not build a site to share the open sources for the phd guys, and provide a way to find the online related material quickly and easily. This is the bible4phd mainly for. Hoping it works. Cheers.

Double Seventh Festival

2012-08-23T04:42:00.000-07:00

Today is the Double Seventh Festival of China, just like the valentine's day in the western country. This is also my fouth thursday since arriving in Singapore, where I will spend my next four years or more. So I am thinking why not record the hard life so called, for english practice, or for watching my struggling lives.