Rachmaninov’s third piano concerto stands out not only for the huge technical challenge it poses to the performer, but moreover for its enchanting nature. The piece has a particularly complex texture and varies in style such that you are constantly surprised by its development. Whatever you make of it, it is surely one of the most complex (master)pieces in the piano repertoire.

Listen or Download:

1st Movement, Allegro ma non troppo

2nd Movement, Intermezzo: Adagio

3rd Movement, Finale: Alla breve

(Performed by Jonathan Oshry, piano.)

If you want an overview of the goal of the project, the Launchpad page probably explains it best:

IRC.NET is a fully-featured IRC (Internet Relay Chat) client library for the .NET Framework 4.0. It aims to provide a complete and accurate implementation of the protocol as described in RFC 2812 (Internet Relay Chat: Client Protocol) as well as supporting de-facto modern features of the protocol, such as ISUPPORT commands and CTCP (Client To Client Protocol).

Oh, and it would hardly be appropriate for an IRC-related project not to have its own IRC channel; feel free to drop by ##ircdotnet over on Freenode. We’re always happy to help.

Overview of Features

• Modern and systematically designed API. Easily integrable into UI/WPF scenarios.
• Full suite of unit tests that interact with live server.
• Detailed error messages provided by the library.
• Comprehensive API documentation (MS HTML Help and MS Help Viewer formats).
• A basic sample with full documentation.
• Connect to and register with multiple IRC servers on arbitrary ports, as either a user or service. SSL support is coming with v0.4.
• Change the user mode and nick name.
• Query the server for information about itself, the network, users, channels, and various other things.
• Track all known users on the server, and store information about them. Receive instant update notifications.
• Join and leave channels, including channels with keys.
• Track the list of users that are currently members of a channel.
• Set and retrieve channel modes (e.g. m, I) as well as channel modes that apply to users (e.g. o, v).
• Kick or ban a user from a channel.
• Send and receive messages and notices to/from other users, channels, and the server.
• Perform WHO/WHOIS/WHOWAS queries on any user and store all received information.
• Configurable rate throttling; a queue of outgoing messages is maintained so as to not flood the server.
• Client-to-client protocol (CTCP) support as a separate layer on top of IRC. Support for all common commands and messages.
• Various non-RFC features in widespread usage, such as ISUPPORT.

The Official Client Application

As a side-note, I am also running a project to create a modern and user-friendly IRC client for Windows 7, under the (temporary) name of Ircsil. The project is still in its early stages, but feel free to check out the work done so far, and even better, show your support. You’re also welcome to visit our IRC channel, #ircsil on Freenode; it’s always full of discussion.

Here’s an screenshot from a recent build, in the hope of garnering a bit of enthusiasm!

Camera eye of HAL 9000 from 2001: A Space Odyssey

The HAL 9000 computer from Arthur C. Clarke’s landmark 2001: A Space Oddyssey film and novel is an early and notable case of a fictional machine that can interpret (and produce) human language, among other abilities. Indeed, it is a machine responsible for one of the most memorable quotes in science fiction film:

David Bowman: Open the pod bay doors, HAL.

HAL 9000: I’m sorry, Dave. I’m afraid I can’t do that.

There is however no need to start worrying about villainous machines eavesdropping on everything we say (or write) yet! A machine capable of understanding natural language need not have any higher-level reasoning capabilities, as I will attempt to show in this article. Still, the association of language ability with that of independent thought is a curious one; something I will perhaps explore in time.

On a more serious note, the reality of machines actually reading human language, in speech or text form, is very likely one of the closest to success of the major goals of artificial intelligence. The field of natural language processing is a surprisingly mature one, dating back as far as the the 1950s, yet the holy grail is still just beyond touching distance (or far beyond even, depending how you look at it). Indeed, speech recognition and text-to-speech has come a long way too, such that reasonably sophisticated and effective algorithms are commonplace on home computers today. Clearly, the processing and interpretation of language is the largest obstacle to “natural” communication with machines. More specifically, the problem lies predominantly in mapping a sentence or phrase, on the surface a string of letters and punctuation, to an abstract concept; something that contains abstract meaning, and that a computer can relate to known information.

The process of “reading”

To begin, we should really define what fundamentally constitutes reading, and the processes it involves. Let’s consider a very simple and straightforward process first, and develop the concept from there. Simply iterating over each word (or group of words) in a sentence and looking them up in a dictionary would be a naive way to consider reading. Immediately though, we see that this completely ignores the structure of the sentence – how the parts of speech fit together. So what about constructing some sort of abstract syntax tree and tagging each word (or possibly group of words) with information about the type and relevance of the word? (Let’s put aside the significant issue of the ambiguity of language for now.) Now we at least have a representation of the grammar/structure of the sentence as well as the definitions of its components, yet something is clearly still lacking. This model has no concept associated with the sentence. What does a perfect knowledge of English grammar and vocabulary tell us without the context in which it is used, be that context the entire Universe? Context is what I define as a set of (complex) mappings between a fragment of language and the underlying concepts, abstract or concrete. Proper interpretation of the grammar and structure of a given language, combined with context, is what is required for natural language understanding, in its most general (loosest) definition. Each is a difficult task in itself, and it may be that a certain degree of overlap is required for things to work.

How humans comprehend speech and text

I shall not delve into this area too deeply, for I’m not a psychologist, and certainly not even psychologists understand properly how we comprehend language. It is however important we get a feel for how the mind processes language and where/how machines might adopt a similar approach, at some level of abstraction. Quite evidently, human listening and reading are very much holistic affairs, so trying to break down the process into parts or stages won’t get us far.

For a start, we must notice that the recognition of words is done in a very approximate way. Tests have shown that we fixate on key words when we read, and that most words are often determined from a few key letters. Changing a high proportion of the letters in text, if done in a certain way, barely impedes our ability to read. Indeed, the mind seems to pick out the structure and regularities in language (and even words) and often fills in the gaps for us. Evidence suggests that we do not interpret words in a dictionary-style fashion, but rather use the context (of varying scope) as well as our familiarity with a word from previous encounters, to give meaning. In this sense, reading is prone to significant errors in humans, as I’m sure we’ve all experienced. There is no reason machines should generally be any more precise in this respect, as we will see later. Do not let the fact that machines are incredibly precise at the “mechanical” level fool you – so are our brains’ neurons!

What allows us to read quickly and effectively more than anything else seems to be the ability to recognise familiar patterns and constructs within text. In fact, I would argue that previous familiarity with words and grammatical constructs plays a crucial role in interpretation of language by evoking certain points or areas of memory. Only when this process is done in a recursive (iterated) fashion does the meaning of some text truly take on form. In a loose sense, perhaps the process of reading can be described as the triggering of a web of interconnected ideas and memories.

Without going to deep here, I believe this holistic interpretation of reading is greatly important to keep in mind for guiding an approach to machine reading. To me, the neuro-psychological specifics are to a large degree irrelevant, whereas if we try to mimic the global picture, and consider implementation secondary – a “top down” creation of sorts – we are more likely to succeed.

How humans learn to read

The continuous process of learning to speak and later to read essentially comes down to a good deal of trial and error. I refer to speaking in addition because it is invariably the first step people take to understanding/producing language. Reading follows much more naturally after it, and indeed begins as a largely verbal/aural skill – never ceases to be in fact, though it may become more subliminal. It is a curious point to note that in ancient times (at least during the Dark Ages), reading silently was a very rare talent that amazed even many educated folk.

Although the way our minds learn to read is largely a hidden affair, it is clear that there is some hardwired ability for language in our brains. When our brains rapidly develop in the early years of our lives, interaction and familiarity with the external world is done largely through feel and sight. This gradually forms a core basis of knowledge/familiarity around which further development can occur. While at first only superficial understanding of the world is gained, it crucially allows the mind to build relationships between and around what is already familiar. It is apparent that, while the mind has a latent ability for reasoning and abstract thought, we are truly shaped by our environment. We ultimately learn advanced (human) skills only through a combination of evolutionary/genetic memory and interaction with the external world.

Can a machine read as we do?

What I have described so far in terms of the process of reading (and its learning) is a complex and many-layered system, though one with a surprisingly small number of core principles.

At the end of the day, natural language and its comprehension is an inherently human endeavour. For this reason, it is belief that true NLP (or rather understanding) ultimately requires strong AI. As I have already stated however, we can achieve much without requiring a full human-level intelligence. It should be no surprise then that some level of compromise is needed to achieve effective NLP at present. While I have stressed that the process of reading is an overwhelmingly holistic affair (though there is some internal structure to the understanding of language), we can not implement AI purely so. Striking a balance between a mechanical algorithm and a level of holism that allows for the manipulation of sufficiently abstract concepts is the key. It is a key, though, well hidden.

A practical solution

A note: It would seem my dedication to writing such megalithic articles as this has worn off over recent times. (This post has been in draft stage since February!) I hope readers will permit me to publish in the current state, so that I may gradually work towards the completion of this last section.

Here are a few notes on where I next intend to explore:

• Human learning. Requires evolutionary/genetic memory to start? Based on general intelligence and experience?
• Machine learning. Can be instilled with knowledge/basic rules by programmer? Based on statistical rules and large corpus of text?
• Mechanical versus “free” (informal) reasoning?
• How much of the process should be instilled before-hand, or learnt cumulatively – what trade off?

And while no saying should be taken at face value, I cannot but agree with the sentiment of this statement. We are all in some sense ‘uneducated men’, whether or not we admit it to ourselves. Just sometimes, thoughts of wisdom expressed in succinct and memorable ways can help us through the journey of life. If they do nothing else, they have the ability to free the mind, which so often imposes its own shackles.

Some time ago I blogged about the meaning of quotations and shared some of my favourites. Of course, my collection is hardly static, and by now I’ve jotted down more than a few others worthy of record. Read, digest, and (I hope) enjoy!

Oscar Wilde (1854 – 1900 AD) – Irish poet and playwright

The moment you think you understand a great work of art, it’s dead for you.

Always forgive your enemies; nothing annoys them so much.

I can stand brute force, but brute reason is quite unbearable. There is something unfair about its use. It is hitting below the intellect.

Anyone who lives within their means suffers from a lack of imagination.

Winston Churchill (1874 – 1965 AD) – British politician, historian, and writer

The power of man has grown in every sphere, except over himself.

He has all the virtues I dislike and none of the vices I admire.

You have enemies? Good. That means you’ve stood up for something, sometime in your life.

To build may have to be the slow and laborious task of years. To destroy can be the thoughtless act of a single day.

History will be kind to me for I intend to write it.

It is a mistake to look too far ahead. Only one link in the chain of destiny can be handled at a time.

Bessie Braddock: Winston, you are drunk!
Winston Churchill: And Madam, you are ugly. And tomorrow, I’ll be sober, and you will still be ugly.

Lucius Annaeus Seneca (3 BC – 65 AD) – Roman philosopher, statesman, and dramatist

There is no great genius without some touch of madness.

John Stuart Mill (1806 – 1873 AD) – British philosopher

Conservatives are not necessarily stupid, but most stupid people are conservative.

The worth of the state, in the long run, is the worth of the individuals composing it.

Mark Twain (1835 – 1910 AD) – American author

When we remember we are all mad, the mysteries disappear and life stands explained.

Carl Gustav Jung (1875-1961 AD) – Swiss psychiatrist

Show me a sane man and I will cure him for you.

Edmund Burke (1729 – 1797 AD) – Irish politician and philosopher

The only thing necessary for the triumph of evil is for good men to do nothing.

Benjamin Franklin (1706 – 1790 AD) – American polymath (politician, scientist, inventor)

Would you persuade, speak of interest, not of reason.

Content makes poor men rich; discontent makes rich men poor.

Being ignorant is not so much a shame, as being unwilling to learn.

Albert Einstein (1879 – 1955 AD) – German theoretical physicist

If you want to live a happy life, tie it to a goal, not to people or things.

God does not care about our mathematical difficulties — He integrates empirically.

Ludwig van Beethoven (1770 – 1827 AD) – German composer and pianist

What you are, you are by accident of birth; what I am, I am by myself. There are and will be a thousand princes; there is only one Beethoven.

Wolfgang Amadeus Mozart (1756 – 1791 AD) – Austrian composer

Neither a lofty degree of intelligence nor imagination nor both together go to the making of genius. Love, love, love, that is the soul of genius.

George Bernard Shaw (1856 – 1950 AD) – Irish playwright

Without art, the crudeness of reality would make the world unbearable.

Gian Carlo Menotti (1911 – 2007 AD) – Italian/American composer

A man only becomes wise when he begins to calculate the approximate depth of his ignorance.

Ayn Rand (1905 – 1982 AD) – Russian/American novelist, philosopher, and playwright

The truth is not for all men, but only for those who seek it.

Evelyn Waugh (1903 – 1966 AD) – English writer

Punctuality is the virtue of the bored.

Miscellaneous

If you love somebody, let them go. If they return, they were always yours. If they don’t, they never were. (Unknown)

Those that will not hear must be made to feel. (German proverb)

You can go visit the proposal right now to get an idea of some of the questions and topics. Or even better, comment and contribute some of your own! If the idea of creating such a community appeals to you as it does to me, please take (literally) a few seconds to log in and follow the fledgling community. By doing this you show support for the idea and are speeding up the process of it becoming a full online community site.

Many unofficial sites that use the Stack Overflow software (the so-called Stack Exchange) system have also sprung up over the past months, perhaps the most active and well-known of these being Math Overflow. (Beware, however, the content is more than a bit scary unless you’re a post-graduate level mathematician!) This surge in popularity has even led to the creation of the Area 51 Stack Exchange site, which is a sort of officially-run staging ground for new Stack Exchange sites. (It does however require a strict process of definition, commitment, and beta testing before such communities are created as websites of there own.) Several communities are already on there way to becoming fully-fledged communities in the theme of Stack Overflow, for topics such as Web Applications, Cooking, Mathematics, and English Language.

What is more, a Physics proposal has been made for a Stack Exchange community, but is still only in its middle stages of creation. What it needs at the moment is what the creators of Area 51 term commitment (users stating that they intend to be active in the new community). No surprise then, that I’m advertising to the physics enthusiasts out there to go and sign up for the new community by committing. It takes no more time than signing in with your Google Account and clicking a button, but will give this community a real chance to develop into something great.

The popularity and sheer visitor count of the Stack Exchange and now the Area 51 websites should indicate that this could potentially be a very active and hugely useful community for physicists and physics students assisting each other in problems and sharing knowledge across the world. Unfortunately the existing attempt at a Stack Exchange community for physics over at physicsoverflow.net has shown little sign of taking off. Let us hope the two sites merge once things take off on the staging ground. Certainly, the process that Area 51 forces such sites to go through does however give every sign of success!

So, I thought I’d take this opportunity to share a brief list of some of the most clever/entertaining/useful apps I have on my iPhone at the moment. Not that anyone with an iPhone doesn’t already have enough, but it’s a handy reference list if you’re being picky about what to install, or browsing through streams of ratings! I’ve also thrown in a few iPhone/mobile-specific websites that are worth noting.

Information and Utilities

• Wikipedia/Wikipanion – pretty similar, but the former is a new official app, and the latter a slightly more established one
• Wolfram – great native interface for accessing Wolfram Alpha
• Google Earth – touch interface for Google Earth
• Tube Map – map and other utilities for London Underground
• Bloomberg – live updates and news for stocks, bonds, and currencies
• GraphCalc – advanced graphing and calculator for mathematical functions
• RedLaser – scans any bar code using camera and looks up best prices online
• iBooks – official app for downloading and reading books from the Apple store
• Stanza – download and read books, with interfaces for websites like Project Gutenburg
• IMDB – browse and view information about films
• Google Translate (website) – instantaneously translate text between any two languages

Media

• BBC iPlayer (website) – watch recent BBC shows anywhere for free
• TVCatchup Mobile (website) – watch UK FreeView channels anywhere for free
• NYTimes – best news app around, though it doesn’t cover local UK news of course
• BBC News – pretty useful app for UK and World news, though could do with a few usability improvements
• Remote – control iTunes on any computer within the local network
• Files (lite) – local file system for viewing images, Microsoft Office, and other files, can upload from anywhere in local network
• Dropbox – upload and download files from/to your space on the Dropbox.com service

Social

• Facebook – a great (and pretty complete) app for accessing Facebook, also an effective time sink!
• Skype – official Skype app, works alomost exactly like the normal phone app, and completely free
• Messenger – official MSN messenger app
• Google Talk – web app, accessible via the GTalk site
• Colloquy – IRC client

Fun and Games

• DoodleJump
• Angry Birds
• iChess
• Scrabble
• Physics Free

Note that most of these apps (and all of the websites) are completely free, though a few cost a small amount of money, typically no more than £1 (or $1 in the US, I presume).

Pyotr Ilyich Tchaikovsky, by Nikolay Kuznetsov, 1893

The genius of Pyotr Ilyich Tchaikovsky is beyond doubt, yet the life and reputation of the man were often greatly troubled. (For that matter, it is hard to think of any great Romantic composer, from Beethoven to Schumann to Chopin, who did not have their fair share of life’s pains.) Not only was he constantly under attack for his homosexuality (which he tried constantly to hide), but his compositions were given a tough time even in his own country. It is not surprising that the portrait taken in his final year shows such a grave expression. His unique yet essentially Western European style was much resented by the the so-called Mighty Handful of contemporary Russian composers, who had different ideals (largely nationalistic). Later in the 20th century, his music was considered somewhat superficial and trivial, yet this view has since disappeared for the most part. His creative talents probably deserve more merit than the layman’s recognition of a few parts from The Nutcracker suite!

Tchaikovsky’s Slavonic March in B-flat minor (often given its French name, Marche Slave) is one of his minor works, but one that stands out for me. Emotionally charged, its mood varies from the sombre (reflecting the Russo-Turkish war of the time) to the hopeful, even cheerful. For sure, there is hardly a piece more evocative of Imperial Russia!

Download and Listen Here

(Performed by the Montreal Symphony Orchestra, 1999.)

View near the entrance of Fingal's Cave on Staffa in the Hebrides isles off Scotland

Felix Mendelssohn was a prolific composer of symphonies, concerti, operas, piano music, and songs, yet the Hebrides Overture stands out among all his works as one of the most beautiful and enchanting compositions of the era. Although you might classify it as a “concert overture”, its lyrical and emotive nature truly makes it unique among all pieces.

The style of Mendelssohn’s music was often criticised within his own lifetime as being too traditional and unadventurous (or even lacking in depth). Fortunately, the composer and his style has found much greater appreciation in recent decades. A curious fact, considering that he did so much to revive the works of J. S. Bach, himself a monumental composer whose music went out of favour for many years following his death. Undoubtedly, the predominance of his contemporary on the German music scene, Richard Wagner, who strongly voiced his antisemitism (Mendelssohn was born of Jewish heritage, despite later becoming a Christian), did nothing to help his popularity. Indeed, it strikes me as a great shame that himself and his music were disparaged so greatly during the 19th century, while arguably lesser composers such as Wagner were promoted. He did however find much popularity in Britain, hence his numerous visits to the island including Fingal’s Cave, situated in the Inner Hebrides, inspiring the piece that is the subject of this post.

Download or Listen Here

(Performed by the Musikkollegium Winterthur orchestra.)

• Permutations with repetition
• Permutations without repetition
• Combinations with repetition
• Combinations without repetition

Worth noting is that the algorithms run purely in-place on the list, and involve no recursion (only a single while loop). While memory usage is minimal, they do of course still run in factorial (or equivalently exponential) time complexity, though it’s well known you can’t do any better than that if you require all permutations/combinations of a given size.

Download the full (documented) code for the utility class here.

All four algorithms have been sufficiently tested and verified for small lists, running on .NET 4.0 (Windows). I would be inclined to bet everything runs perfectly well on Mono too. Needless to say, bug reports and feedback are welcome.