In[1]:= Fourier[{0.007 + 0.01 I, -0.002 - 0.0024 I}]
Out[1]= {0.00353553, 0.00636396}
If you upgrade to 7.0.1, it becomes:In[1]:= Fourier[{0.007 + 0.01 I, -0.002 - 0.0024 I}]
Out[1]= {0.00353553 + 0.00537401 I, 0.00636396 + 0.00876812 I}
ProteinData["A2M", "MoleculePlot"] and then rotate the 3-D structure of protein and then ask the girl next to you "Wanna have dinner with me some time?"
>>> for i,arr in enumerate([6,3,2,3,4]):
... print i, arr
...
0 6
1 3
2 2
3 3
4 4
neighbors. Without enumerate, I need these two lines to pick neighbors one by one:
for i in xrange(0,len(neighbors)):
w= neighbors[v][i];
w:for i, w in enumerate(neighbors[v]):
# Python implementation of Prim's algorithm
# by Forrest Sheng Bao, Dept. of Computer Science, Texas Tech
# http://fsbao.net forrest dot bao at gmail dot com
# This code implements the example on P. 571 of the famous
# "Introduction to Algorithms," 2nd ed., by Cormen, Leiserson, Rivest and Stein
# The connection matrix of the graph is represented as matrix A in the problem
# So it doesn't matter if you don't have the book. The vertexes are indexed from 0.
# The program is a free software. You may use, distribute and copy it under the
# terms of GNU General Public License version 3.
# http://www.gnu.org/copyleft/gpl.html
# Expected output:
# $ python maxspanning.py
# vertex 0 has just been added into the growing spanning tree
# vertex 1 has just been added into the growing spanning tree
# vertex 2 has just been added into the growing spanning tree
# vertex 8 has just been added into the growing spanning tree
# vertex 5 has just been added into the growing spanning tree
# vertex 6 has just been added into the growing spanning tree
# vertex 7 has just been added into the growing spanning tree
# vertex 3 has just been added into the growing spanning tree
# vertex 4 has just been added into the growing spanning tree
from numpy import *
def spanningTree(n,A):
# neighbors[n]: // neighbors[i] is the list of neighbors of i in graph A
neighbors=[];# neighbors[n], neighbors[i] is the list of neighbors of i in graph A
for i in xrange(0,n):
for j in xrange(0,n):
neighbors.append([]);
if( A[i,j] != 0):
neighbors[i].append(j)
treeNeighbor=[];
# initially treeNeighbor[i] = -1;
# during spanningTree(),
# treeNeighbor[i] == p if selected[p] is true and A[i,p]
# is the shortest distance from i to the current tree.
# treeNeighbor[i] == -1 if p is not a neighbor of any node of
# the current spanning tree.
# exception: 0 is always seleted first and treeNeighbor[0] is -1
selected=[];#selected[i]=1: i is in spanning tree; 0: otherwise , initialized to be 0
distance=[];#distance[i]: the shortest distance from i to tree, initialized to be +1
for i in xrange(0,n):
treeNeighbor.append(-1);
selected.append(0);
distance.append(100); # \infty for positive case, 1 for negative case
first = 1; # a marker to mark, first =1 if the abitrary starting point is to be selected.
for i in xrange(0,n):
v = findMin(n,first,selected,treeNeighbor,distance);
print "vertex", v, "has just been added into the growing spanning tree"
first = 0;
selected[v] = 1;
# add neighbors of v to treeNeighbor[] and update their distance to current spanning tree
for i, w in enumerate(neighbors[v]):#each w \in neighbors[v]
#w= neighbors[v][i];
if selected[w]==0 : #only update vertexes that are NOT on the tree now
if A[v,w] < distance[w]:
distance[w] = A[v,w];
treeNeighbor[w] = v; #treeNeighbor, neighbors to current spanning tree
#A[w,v]is the shortest path from w to current tree.
return treeNeighbor;
def findMin(n,first,selected,treeNeighbor,distance):
if (first == 1):
v = 0;
treeNeighbor[0] = -1;
return v ;
else:
min_distance=100; #\infty for postive case, 0 for negative case
for v in xrange(0,n):
if (selected[v]==0) and (treeNeighbor[v] != -1) and (distance[v] < min_distance):
# the new node must be not on the current tree and be reachable to the tree in one hop and the shortest one to the current tree
min_v = v;
min_distance = distance[v]
return min_v;
A=[\
[0, 4, 0, 0, 0, 0, 0, 8, 0],\
[4, 0, 8, 0, 0, 0, 0, 11, 0],\
[0, 8, 0, 7, 0, 4, 0, 0, 2],\
[0, 0, 7, 0, 9, 14, 0, 0, 0], \
[0, 0, 0, 9, 0, 10, 0, 0, 0],\
[0, 0, 4, 14, 10, 0, 2, 0, 0],\
[0, 0, 0, 0, 0, 2, 0, 1, 6],\
[8, 11, 0, 0, 0, 0, 1, 0, 7],\
[0, 0, 2, 0, 0, 0, 6, 7, 0]\
]
A=array(A)
R= spanningTree(9, A)
by Forrest Sheng Bao http://fsbao.net
Python is my favorite programming language. There are many Python editors, debuggers and IDEs. Some good editors/IDE are geditor(comes with Gnome desktop by default), SPE (Stani's Python Editor) and Eric. There is a debugger with GUI called Winpdb. The default debugger is IDLE, developed by Python Software Foundation.
If I don't need to debug my program, I will only use geditor or even vim simply. If I need to debug, I will use Eric. In Eric, I have all the buttons I need on the toolbar and I can debug it without calling other programs. A trick of Eric is that I can use regular expression to hide some variables I don't want to see, as you can see in this snapshot.
The reason I mention Winpdb is because sometimes I am so lazy to hide variables I don't want to see. I just want to view certain varibales I am interested in. Winpdb provides me a way in its command console. I just need to type in "v variable_name" then I can see the value of a perticular variable.
by Forrest Sheng Bao http://fsbao.net
You know the movie Ironman, right? You think it's cool, right? But do you know which OS supports those cool stuffs? The answer is our Linux!
I checked out a DVD from my university library and watched a short video about how those visual effects were made. Then I found the desktop environment they used are just Gnome, a famous desktop environment on Linux.
Here are 3 snapshots.
by Forrest Sheng Bao http://fsbao.net
The PLoS One editorial office gives a quick response on accepting LaTeX files. Great news for people like me. Thanks, PLoS One editorial office. Now PLoS One is accepting LaTeX files in fields math, physics, engineering, computation biology and chemistry. http://www.plos.org/cms/node/451
But I still have some concerns about the LaTeX template they provide. As everyone knows, the editorial office should give us a LaTeX class file (*.cls) or a style file (*.sty). But I did not see them. We have to play tricks in the TeX file. For example, for the title, you can NOT state as \title{My Paper}. Instead, you have to use several commands: \begin{flushleft} {\Large \textbf{Title} } \end{flushleft}
The idea of LaTeX is to delivery authors from typesetting, thru separating the contents and appearance. But now we are doing the same thing, as in Microsoft Word. Here verbose LaTeX commands replaces mouse-click in Microsoft Word. What is a title of a paper in LaTeX? The authors do not have to think about it. They don't have to know the alignment, the font size and the boldness. They just need to simply tell that this is the title by \title{My title}.
The reason I use LaTeX, not only because my papers have "heavy math," but also because I want to separate my contents from the appearance, thus the layout and typesetting. So, I am thinking could someone write a class file or style file for PLoS One, like Elsevier or IEEE. I can volunteer that. It seems not very complex from standard LaTeX article style.
Anyway, it's not the biggest deal. It's way better than asking me convert to Word or RTF. I just need to edit a few LaTeX commands to reach their requirements.
================ Below is my original complaint =================
I got a paper accepted by PLoS One. But I am very uncomfortable about the accepted file format. I am very sad to know that PLoS requires authors to convert LaTeX into RTF. http://www.plosone.org/static/latex.action In many fields, such as math, physics, computer science and electrical engineering, LaTeX is the dominant tool to write papers, because we have way too many equations, plots, diagrams and tables, cross-references and references in a single paper. It is a great waste of time to manage the layout and typesetting manually in Word or RTF.
AMS (American Math Society), AIP (American Institutes of Physics), IEEE (Institute of Electrical and Electronic Engineerings) and ACM (Association for Computing Machinery
), are leading societies in math, physics, electrical engineering and computer science. They journals and conferences all accept LaTeX files and thus give authors full freedom on writing papers. It is a nightmare to write a paper in Word or RTF. You have to do everything manually. Why not leave those stupid things to computers and focus more on intellectual things?
Science, Nature and PNAS also have their own LaTeX templates and accept LaTeX files.
Mainstream publishers, such as Springer or Elsevier, even designed beautiful LaTeX templates.
Not accepting LaTeX files makes PLoS very unfriendly to scientific community. In order to simplify paper writing and save time, authors may turn to other journals.
If you accept LaTeX files, authors can even provide PDF files directly. This could save time of editors too.
Plus, academia should prefer free and open source software, just as we prefer CC license and open access idea. LaTeX is totally free ("free" as in "free speech" and "free" as in "free beer"). It is so ugly to write papers in Microsoft Word.
"I hope to die before I have to use Microsoft Word" - Dr. Donald E. Knuth, Professor Emeritus, Dept. of Computer Science, Stanford University