# Zombies, Org-mode and Emacs

### Using Org-babel to create Graphviz graphs in Emacs

I was playing around with Graphviz inside orgmode inside Emacs. Come the Zombie Apocalypse I'll be prepared, thanks to Emacs and Orgmode.
If you are interested in graphviz, you can click on any graph in this gallery and see the graphviz source for the graph.

I wrote the graph source first in Emacs in Orgmode 7.5. Here's the src for experimenting with graphs in orgmode using the new <a href="http://j.mp/l6chaqorgmode.org/worg/org-contrib/babel/">org-babel</a>, which lets you evaluate code in special code sections right inside of Emacs:

digraph D {
size="8,6"
node [ shape = polygon,
sides = 4,
distortion = "0.0",
orientation = "0.0",
skew = "0.0",
color = "#aaaaaa",
style = filled,
fontname = "Helvetica-Outline" ];
apocalypse [sides=9 skew=".32" color="purple"]
apocalypse -> zombie
apocalypse -> zombies
shovel [skew=".56" color="#aa2222"]
subgraph singular {
label="one"
color=purple
zombie -> shovel [color="#440000"]
shovel -> run
}
run [sides=9, color=salmon2];
subgraph plural {
label="many"
color=red
zombies -> run [color="#00a4d4"]
}
}


Then inside the buffer you can evaluate the code with "C-c C-c", and you can see the results of evaluating the code with "C-c C-o". This is made possible by Org-babel, a cool tool that allows you to run scripts from different languages in a single Org-mode buffer. Not only that but you can pipe output from one code block to another code block written in a different language. I will have more blog posts about this in the future. Org-babel is a part of Org-mode since Org-mode 7.x or so. Exciting stuff!

Org-babel Documentation
Graphviz

### Here's some LaTex to try

Exponential Growth and Decay Equation

$$\displaystyle\boxed{P(t) = P_0 e^{kt} }$$

What is the rate of decay "k", given a certain half-life of "t" years:

$$\displaystyle\boxed{ k = \frac{ln(\frac{1}{2})}{t} }$$

What is the half-life "t", given a rate of decay, "k":

$$\displaystyle\boxed{ t = \frac{ln(\frac{1}{2})}{k} }$$