Chymeric Tutorials

Do awesome stuff - awesomely.

Per-attack Risk Dice Odds

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In Risk-like games, players face off against each other on maps divided into territories. One player may conquer the territories of another by eliminating all of the other’s units from a said territory. Units can be eliminated with the throwing of the dice, and a unit is lost for every instance where the opposing player has a higher score on one cast die. The throwing of the die is governed by the following rules:

  • The defender rolls a maximum of 2 dice (one per unit - contingent on the unit number on the attacked territory).
  • The attacker rolls a maximum of 3 dice (one per unit - excluding the last unit and contingent on the unit number on the attacking territory).
  • Only the top dice are considered if a player throws more dice than his opponent.
  • Dice are paired with each other in an ordinal fashion.

There are already texts providing more wide-ranging whole-battle predictions (as for instance here), and closed-source (and in this particular case inaccurate) battle simulators. Here we try to offer a transparent formulaic reference and odds table for all single-attack scenarios.

Per-photo Model Release Form

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Model release forms help photographers secure the freedom to publish and sell their photography work. One common issue with model release forms (especially in the context of informal photo sessions) is that they are tailored to the practice of professional photography, and commonly grant the photographer all rights to all pictures they may have taken of the model. While for professional models this might not be an issue, for relatives, friends, and acquaintances of the photographer such a commitment becomes daunting.

Here we present a model release form concept based on encryption technology which you can use to transfer rights for single photographs.

Raspberry Pi Stage 4 Gentoo Tarball

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Tarballs (a term for .tar archives) are a common medium for installing the Gentoo Linux operating system. The standard Gentoo installation starts with a non-bootable “stage 3” tarball, which includes only very limited software. As discussed in a previous article, on the Raspberry Pi - and other embedded systems - it is in certain respects better to start off with a bootable (and wifi-capable) tarball.

For these purposes we are publishing a stage 4 tarball with all the basic software you need on the Raspberry Pi - including the sys-kernel/linux-firmware package for broad wifi-device support and a Git repository for customizing and deploying the newest Raspberry Pi kernel sources from upstream. Though the archives total under 1 GB in size, we recommend you use at least an 8 GB SD card for use with your Raspberry Pi.

Gentoo for the Raspberry Pi

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Gentoo is a Linux distribution which excels at flexibility and recommends itself for easy customization. These qualities make it especially well-suited for scientific computing or for dedicated systems. The Raspberry Pi is one of the most popular (though not the only - see Cubieboard as an alternate example) single-board computers to date, and is often deployed for dedicated tasks: scientific computing, home automation, etc.

Installing Gentoo on a dedicated platform makes it easy for the user to strip down his system to suit his needs precisely - e.g. in the guise of an ultra-minimalist installation. Here we provide an overview of current means of installing Gentoo on your Raspberry Pi.

Mkstage4 - Stage 4 Tarballs Made Easy

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Stage 4 tarballs are bootable, fully working, self-sufficient Gentoo Linux distributions. They include a complete Gento environment, which you can directly boot up and use.

Stage 4 tarballs are very well suited for system backups or use cases where chrooting and emerging your basic system requirements can become very tedious. Situations in which stage 3 installation is difficult include:

  • Installing Gentoo on machines with limited resources for compilation (e.g. many ARM family platforms)
  • Installing Gentoo for machines which do not support standard live CD/USB distributions

Free and Open Science for Your Thesis

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Topics such as open peer review, open data, and open notebook science are of increasing interest to the scientific community. Many of the concepts behind this new spin on science are rooted in the FOSS (Free and Open Source Software) world and draw credibility from its staggering success. As such, we would refer to the aforementioned set of trends in science as FOS (Free and Open Science).

With so much talk about FOS going on - and even spilling over into high-profile editorials about publication review - it is distressing how little FOS is actually taking place. Talking about the next big thing is indeed quickening, but we would rather show you how to become a part of it. And what better place to start your voyage into both academia and the FOS world than your thesis or dissertation?

Bash Cheat Sheet

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This is a collection of bash scripts solving a series of eclectic use cases which we have encountered in the past. These instructions use linux commands and directory structures.

Portage Cheat Sheet

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This is a small sample of commands dealing with a series of simple use cases involving Portage. For all the code examples please note that emerge needs to be run as root. Other commands such as equery can be run as user. The Gentoo Wiki hosts a longer (though different) Portage/Gentoo cheat sheet on this page.

Miscellaneous Cheat Sheet

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This is a collection of workflows, commands, or bash scripts solving a series of common use cases. These instructions use linux commands and directory structures.

Write Octopress Themes

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Octopress is a fast and clean blogging platform which advertises itself as “a blogging framework for hackers”. Here we provide the first comprehensive documentation on how to best create new Octopress themes by hacking the default theme (or any theme based on it). We base our instructions both on general tools which you can use for better hacking and on solutions to popular use cases.