## Friday, November 28, 2014

### Prime Sextuplets

A couple of days ago, the Riecoin project (a virtual currency and distributed computing platform) posted a press release announcing they have quietly broken the record for the largest prime number sextuplet:

A prime sextuplet consists of six prime numbers packed together as tightly as possible. For sextuplets, "as tightly as possible" means that the largest is 16 plus the smallest of the numbers.

The smallest prime sextuplet is {7, 11, 13, 17, 19, 23} and generally they take the form of a prime number `N` such that these six numbers are all prime: {N+0, N+4, N+6, N+10, N+12, N+16}.

It's kind of neat that you can use Factor to confirm their result:

```USE: math.primes
689702036532655186685581028503873005405874329363269153979622096014346785019088707220301256048568366498602811964467654774670820091972463194208186476882699386082393716593309811371422836387527549653095824492750394092045532275098135652952423078356472379653908988713872759020566218763497459878106775183203857648413997381256598543877696056491021898353604500233203798629403923570165634119564742536549584121471881689569379964364152289494693118199337926886001843460903637314310532482306798517536171711379098711480663572269535063407688377687623951196977582998449120940358830276897328119483620011984713125859631603652231485340570118364685553782567043880668996080767
{ 0 4 6 10 12 16 } [ + ] with map [ prime? ] all? .```

Factor uses an implementation of the probabilistic Miller-Rabin primality test in the math.primes.miller-rabin vocabulary, which on my laptop takes just over 3 seconds.

## Saturday, November 22, 2014

### Factor Tutorial

Andrea Ferretti has posted a great tutorial about Factor!

From the announcement on the mailing list:

```Factor has a lot of documentation in the listener, but I have
tried to cover some topics that are present in the official
docs, but scattered throughout it, so that they were not clear
to me at the beginning.

These include for instance:

- the central concept is function composition, the stack is more
of a detail
- how simple is to deploy program and scripts
- what tools are there: linter, inspector, unit testing support,
reverse lookup of function uses...
- what model of multithreading and async I/O are used
- how to make use of multiple cores
- in what sense Factor has an object system
and more```

Check it out!

## Sunday, November 2, 2014

### Factor 0.97 now available

"If birds can glide for long periods of time, then... why can’t I?" - Orville Wright

I'm very pleased to announce the release of Factor 0.97!

OS/CPUWindowsMac OS XLinux
x86
x86-64

Source code: 0.97

This release is brought to you with over 1,400 commits by the following individuals:

Alex Vondrak, Andrew Pennebaker, Benjamin Pollack, Björn Lindqvist, CW Alston, Doug Coleman, Erik Charlebois, Fred Alger, Iskander Sitdikov, John Benediktsson, Jon Harper, Loryn Jenkins, Paul Woolcock, Roc King, Samuel Tardieu, Steven Stewart-Gallus, and @Profpatsch

Besides some bug fixes and library improvements, I want to highlight the following changes:

Some possible backwards compatibility issues:

• Fixed `mask?` in math.bitwise to be more correct
• Fixed bias in Mersenne Twister random number generator
• Better support for shebang (no longer need a space after `#!`)
• `io-error` now lives in the libc vocabulary
• sender stubs in cocoa.messages now named by method signature
• `filter` now allocates length of `seq`, not `exemplar`.
• Removed `make-assoc` in favor of explicit `get`'s.

Some of the improvements to FUEL, Factor's emacs mode:

• Modernize for emacs 24.3
• Prepare FUEL to be uploaded to MELPA
• Change font locking and syntax highlighting
• Make fuel-help work for vocabularies also
• New minor mode: fuel-autohelp-mode
• Fix word help to use correct vocabulary using list
• Variable controlling whether fuel-mode is loaded automatically
• Fixes to table rendering

## What is Factor

Factor is a concatenative, stack-based programming language with high-level features including dynamic types, extensible syntax, macros, and garbage collection. On a practical side, Factor has a full-featured library, supports many different platforms, and has been extensively documented.

The implementation is fully compiled for performance, while still supporting interactive development. Factor applications are portable between all common platforms. Factor can deploy stand-alone applications on all platforms. Full source code for the Factor project is available under a BSD license.