Josh Bryan's Random Thoughts

New Career

Tue, 02 Apr 2013 14:38:24 +0000

Recently I did something crazy. I left a great job at University of Chicago developing data transfer software for the research community to start my own company. The company, Clear Abacus, will be providing a software-as-as-service supply chain optimization engine that facilitates transport routing and loading decisions. I am looking forward to all the challenges that lie ahead, both technical and personal.

More WebGL Experiments

Sun, 15 Jul 2012 22:23:33 +0000

I just posted a new WebGL demo. This is GPGPU based particle demo. Particles of “negligable” mass are spawned along the x axis with arbitrary velocities. There is an invisible mass in the center attracting all particles. Watch the system evolve the camera rotates around the system. All particle motions are computed on the GPU using textures to store velocity and position data. You can read more about it on GitHub.

WebGL GPU Accelerated Game of Life

Sun, 15 Apr 2012 02:52:04 +0000

I’ve been playing with WebGL recently and have been putting together some toy projects. Recently I created a GPU accelerated version of Conway’s Game of Life. If you have Google Chrome or the open source Chromium browser, you can view it on my WebGL Github page. You will need to have a reasonable graphics card as it renders 3 parallel Games of Life on a 4096x2048 grid with a 3d torus topology. You can zoom in with the scroll wheel to see more detail. Each color (red, green, blue) is a separate game of life. You can also activate blocks of cells by clicking with the mouse. Its mesmerizing fun for hours!

Reinforcement Learning Demo

Fri, 17 Dec 2010 05:40:48 +0000

I recently put together a short demo about Q learning and SARSA learning for a class I was taking. The demo involved running the two algorithms in parallel in a simple maze world. The world, the agent, and the learned Q function are drawn using OpenGL.

A few people suggested I make the presentation and demo code available for others, so here it is: You can download the code for the reinforcement learning demo from GitHub, and I have attached the presentation as well.

More NXT Tools

Tue, 05 Jan 2010 03:25:00 +0000

Over the holiday, I’ve added a few tools to the NXT Tools I’ve been developing. One is a simple python tool to use gstreamer to convert any gstreamer readable audio format to the NXT’s native RSO format. Also I’ve added a very basic tool to use a computer to interface a Wii remote (aka wiimote) to the NXT brick.

Fuse + Python + Lego NXT

Tue, 15 Dec 2009 20:18:18 +0000

I’ve been recently playing with my new Lego NXT robotics kit. Being a Linux nerd, I naturally wanted to do the programming on Linux using languages I like. To this end, I’ve been using the nxt-python project and NXC. However, I found the nxt-push script a little cumbersome and not very user friendly, and the nxt-filer gui was less than useful. I didn’t want to develop a complete file manager interface. After all, file managers have been redesigned and reimplemented a million different ways. All I really needed was a file interface to the NXT. Enter Fuse. So, I spent some time yesterday and developed a Fuse interface for the NXT using nxt-python and fuse python bindings. You can find the interface in, what will be, a collection of tools for manipulating and controlling the NXT brick on GitHub.

Git ... my favorite vcs

Sat, 14 Nov 2009 19:50:30 +0000

After having used CVS, Subversion, and Perforce, I’ve recently been using Git for all of my version control. The two things I like about above the others mentioned are its speed and trivial and intuitive branching. Though I can’t say I was ever a fan of CVS branches, I always found that the subversion/perforce approach of just creating another directory when you want to branch to somewhat ignore the semantics of being a branch. Why shouldn’t every version be a new directory? Obviously that would get cluttered and confusing. Why would you not expect the same of branches? Yes, I understand that directory copying is cheap in Subversion and Perforce, and I understand they do preserve history, but I expect branches to split and merge and though directories do represent the splitting very well, they unfortunately don’t represent the concept of a merge very well. Git on the otherhand, has explicit branches that are separate from the concept of a directory. Plus, it has many powerful tools for managing those branches, not to mention GitHub.

Life Update

Sat, 14 Nov 2009 19:38:28 +0000

I’ve been a little busy … well, very busy … this last year, so here is a little update about projects in my life. I finished up my masters thesis this last semester, and started work toward my Ph.D. in computer science at UIC. I am researching rationality in multiagent settings for the UIC Multi Agent Systems laboratory. Particularly, I am looking at ways to update POMDP models from agent experience. Between school, various freelance projects, and a short year long career at CashNetUSA, I’ve been pretty busy and haven’t been posting much, hopefully that will change.

Colored man pages

Fri, 05 Sep 2008 20:00:58 +0000

I just discovered this very cool tip. If you want a colored man pages, adding the following to your environment does it:

` export LESS_TERMCAP_mb=$’\E[01;31m’ export LESS_TERMCAP_md=$’\E[01;31m’ export LESS_TERMCAP_me=$’\E[0m’ export LESS_TERMCAP_se=$’\E[0m’ export LESS_TERMCAP_so=$’\E[01;44;33m’ export LESS_TERMCAP_ue=$’\E[0m’ export LESS_TERMCAP_us=$’\E[01;32m’ `

I found the tip while searching for a way to preserve the colored output of grep after it has been piped into less. ‘less -r’ preserves the terminal escape sequences from the input. The following will get preserve the colors:

` grep –color=always | less -r `

Origin of Wealth

Sat, 16 Aug 2008 21:21:28 +0000

Origin of Wealth is a very entertaining and captivating survey of recent developments in economics. He repeatedly takes traditional economic theories to task for failing to match real world empirical data while painting a picture of the economy as a complex, adaptive, and evolutionary system rather than the traditional overly simplistic system of market equilibrium. This is definitely worthwhile read.