user
blokhead
<h2>About me:</h2>
My sig (similar in spirit to [id://290607]):
<code>
perl -le 'exp tr qw s my not vec eq abs do le chop q ge print
lc if sort s qq socket y qx cmp s q qq or rand chop'
</code>
Here is a related hello world:
<code>
sort cos or s qq q and s
m m print chr ord for qw
q hex eval le lt oct q m
and eval xor uc print lc
qq m m and eval qq x not
sin print chr ord for qw
q warn open ref le do qx
xor sleep log print qq q
q if localtime sqrt chop
</code>
<!-- ####################################### -->
<h2>My bookmarks:</h2>
I tend to bookmark nodes related to theoretical topics like applied discrete math, algorithms, computability & complexity.
<ul>
<li>[id://25833]
<li>[id://134202]
<li>[id://224866] (expressivity of Perl regexes)
<li>[id://227909] (except that [id://227946|this reply] is dead wrong)
<li>[id://273638] (joint Kolmogorov complexity approximation)
<li>[id://428614] (halting problem undecidability proof in 3 lines of perl)
<li>[id://428794] (modern computers = finite state machines)
<li>[id://432598] (NP-complete subset sum in disguise)
<li>[id://436872] ("NP-complete" ≠ "don't bother")
<li>[id://493575] (algorithmic analysis & assumptions)
<li>[id://496388] (NP-complete bin-packing in disguise)
<li>[id://540810]
<li>[id://573138]
</ul>
And a handful of fallacious uses of theoretical computer science (the hall of shame!):
<ul>
<li>[id://227946] (n/2 ≠ log(n))
<li>[id://284516] (decision properties of regular languages are decidable)
<li>[id://436070] (halting problem ≠ infinite loop)
<li>[id://501536] (halting problem ≠ Church-Turing thesis)
</ul>
I also have a soft spot for iterators that generate combinatorial objects:
<ul>
<li>[id://386571|Partitions of integers & sets]
<ul>
<li>[id://533530]
<li>[id://533164]
<li>[id://621859]
</ul>
<li>[id://406984|Restricted integer partitions] (i.e, making change for an amount)
<ul>
<li> [id://546438]
<!-- <li> [id://546465] (callback-based) -->
</ul>
<li>[id://371228|Combinations] (subsets of a fixed size)
<li>[id://128293|Power set] (all subsets)
<li>[id://29374|Permutations] (works for multisets, too)
<li>[id://519815|Derangements] (permutations with no fixed points)
<ul>
<li> See also [id://728778] for how to uniformly sample derangements
</ul>
</ul>
Techniques/inspiration for writing iterators in general:
<ul>
<li>[http://www.perl.com/pub/a/2005/06/16/iterators.html|Understanding & Using Iterators] (writing encapsulated iterators; offsite)
<li>[id://458418] (converting recursions into callback-based iterators).
<li>[id://522316] (callback-based iterators with NestedLoops)
<li>[id://640390] (another general-purpose iterator transformation)
<li>[http://www.theory.cs.uvic.ca/~cos/cos.html|Combinatorial Object Server] (offsite)
</ul>
Other miscellaneous useful nodes:
<ul>
<li>[id://284436]
<li>[id://273638] (approximation of mutual information, using compression)
<ul>
<li>[id://640714]
</ul>
<li>[id://541740] (Y combinator)
<ul>
<li>[http://use.perl.org/~Aristotle/journal/30896|Aristotle's use.perl journal entry] on Y combinators
</ul>
<li>[id://553889]
<li>[http://www.dangermouse.net/esoteric/intelligentdesignsort.html|My new favorite sorting algorithm] (offsite, not safe for the humor-deficient)
<li>[http://www.securiteam.com/securityreviews/6D0042AEUQ.html|Perl Format String Vulnerabilities] -- good overview of s/printf security issues (offsite)
<ul>
<li>[id://330838]
<li>[id://406717]
</ul>
</ul>
<h2>My contributions:</h2>
Here are some of my highest-ranked nodes:
<ul>
<li> [id://290607]
<li> [id://329492]
<li> [id://298341]
<li> [id://298877]
<li> [id://433169]
<li> [id://438118]
<li> [id://583727]
</ul>
Code snippets I've posted that might be of general interest (and things I keep having to search for):
<ul>
<li>[id://242751]
<li>[id://301122]
<ul>
<li>See also solutions to [http://osdir.com/ml/lang.perl.qotw.discuss/2005-01/msg00003.html|Perl QOTW]
</ul>
<li>[id://312367]
<li>[id://325389]
<li>[id://357826] (see very bottom 2 lines)
<li>[id://371228]
<li>[id://386571]
<li>[id://453733]
<li>[id://463519]
<ul>
<li>[id://544766] (with captures)
</ul>
<li>[id://475645] (ranking & unranking combinations)
<ul>
<li>[id://608176]
</ul>
<li>[id://522270]
<li>[id://528524] (representing arithmetic expressions for pretty-printing)
<li>[id://533530]
<li>[id://547026] (code for calculating GCD with [http://mathworld.wolfram.com/BezoutNumbers.html|Bezout coefficients]; i.e, the extended Euclidean algorithm)
<li>[id://621859]
</ul>
I like to ramble about theoretical mumbo-jumbo:
<ul>
<li>[id://348555] (NP-complete problem in disguise)
<li>[id://347536] (secret-sharing and information theory)
<li>[id://390969] (information theory)
<li>[id://406290] (universality of computational models)
<li>[id://423543] (decision problems of regular languages)
<ul>
<li>[id://531742]
<li>[id://588368]
<li>[id://757306]
</ul>
<li>[id://433921] (decision tree learning)
<!-- <li>[id://453676] (dynamic programming, even though my assumptions about the problem were wrong: see [tilly]'s response) -->
<!-- <li>[id://458197] (dynamic programming) -->
<li>[id://498965] (pseudorandom generation)
<li>[id://508728] (recasting a problem in terms of regular languages)
<li>[id://644964] (an application of biconnectivity in graphs)
</ul>
<!-- ####################################### -->
<h2>Evolutionary algorithms links:</h2>
In a previous life, I was very interested in evolutionary algorithms. Here are some (biased) links, which are by now terribly out-of-date:
<p>
Perl Modules:
<ul>
<li>[http://search.cpan.org/dist/Algorithm-Evolve/|Algorithm::Evolve], by me! Flexible enough for lots of experimenting, but not comprehensive.
<li>[http://opeal.sourceforge.net/|Algorithm::Evolutionary] probably most complete (and complex).
<li>[http://search.cpan.org/dist/AI-Genetic/|AI::Genetic] also looks like a good choice, though I haven't looked at it throroughly.
<li>[id://81678], no crossover operators.
<li>[http://www.skamphausen.de/software/AI/ga.html|AI::GA], little control over selection/replacement. String chromosomes only.
</ul>
Other articles/resources with a decidedly Perl flavor:
<ul>
<li>[id://298877] by yours truly.
<li>[http://www-106.ibm.com/developerworks/linux/library/l-genperl/?open&l=805,t=grl,p=genPerl|Genetic algorithms applied with Perl], from IBM's "Cultured Perl" column
<li>[http://geneura.ugr.es/~jmerelo/evolutionary-computation-perl/book1.html|Evolutionary computation in Perl] and some [http://geneura.ugr.es/~jmerelo/yapc-europe-slides/text0.htm|YAPC presentation slides] from the author of [http://opeal.sourceforge.net/|Algorithm::Evolutionary]
<li>Online lecture notes: [http://www.math.iastate.edu/danwell/ma378/math378.html|Optimization & Modelling With Artificial Life], by Dan Ashlock (my old professor)
</ul>
Misc:
<ul>
<li>[id://31147]. I also wrote a reimplementation of this idea using my [cpan://Algorithm::Evolve] module. It's included in the distribution's examples.
<li>[id://432801]
</ul>
<h2>Random:</h2>
What famous people had to say about me:
<ul>
<!-- http://www.lhup.edu/~dsimanek/muirbook.htm -->
<li><i>"The vanity of teaching doth oft tempt a man to forget he is a blockhead."</i>
<br> -- George Savile, first Marquis of Halifax, 1633-1695
<!-- http://www.brainyquote.com/quotes/keywords/blockhead.html -->
<li><i>"The great person is ahead of their time, the smart make something out of it, and the blockhead, sets themselves against it."</i>
<br> -- Jean Baudrillard
<li><i>"A learned blockhead is a greater blockhead than an ignorant one."</i>
<br> -- Benjamin Franklin
<li><i>"No man but a blockhead ever wrote except for money."</i>
<br> -- Samuel Johnson
<li><i>The bookful blockhead, ignorantly read
<br>With loads of learned lumber in his head.</i>
<br> -- Alexander Pope
<li><i>"The liar at any rate recognizes that recreation, not instruction, is the aim of conversation, and is a far more civilised being than the blockhead who loudly expresses his disbelief in a story which is told simply for the amusement of the company."</i>
<br> -- Oscar Wilde
<li><i>"A grave blockhead should always go about with a lively one - they show one another off to the best advantage."</i>
<br> -- William Hazlitt
<!-- http://www.giga-usa.com/quotes/topics/blockhead_t001.htm -->
<li><i>"A blockhead cannot come in, nor go away, nor sit, nor rise, nor stand, like a man of sense."</i>
<br> -- Jean de la Bruyere
<li><i>"There never was any party, faction, sect, or cabal whatsoever, in which the most ignorant were not the most violent; for a bee is not a busier animal than a blockhead."</i>
<br> -- Alexander Pope
<li><i>"Being a blockhead is sometimes the best security against being cheated by a man of wit."</i>
<br> -- François, Duc De La Rochefoucauld
<li><i>"When there is sympathy, there needs but one wise man in a company and all are wise,—so, a blockhead makes a blockhead of his companion. Wonderful power to benumb possesses this brother."</i>
<br> -- Ralph Waldo Emerson
</ul>
<!-- ####################################### -->
Silly Perlmonks milestones:
<ul>
<li>2003-10-12 • 197 posts • 3000 xp • 228th saint
<!-- <li>2004-02-02 • 224 posts • 4186 xp • <tt>$blokhead->{xp} == $[merlyn]->{writeups}</tt> -->
<li>2004-05-13 • 278 posts • 5000 xp
<li>2004-09-06 • 334 posts • 6000 xp
<li>2004-10-28 • 360 posts • 6400 xp • top 100
<!-- <li>2005-02-22 • 375 posts • 6817 xp • 10^6 points until level [vroom] -->
<li>2005-03-10 • 385 posts • 7000 xp
<li>2005-10-04 • 437 posts • 8000 xp
<!-- <li>2006-02-27 • 475 posts • 8675 xp • top 90 -->
<li>2006-04-29 • 489 posts • 9000 xp • 90th Prior
<li>2007-03-24 • 526 posts • 10000 xp
<li>2007-12-17 • 575 posts • 11000 xp
<li>2009-10-14 • 631 posts • 12000 xp • 102nd Monsignor (I sure have slowed down!)
</ul>
Monks I've met in meatspace:
<ul>
<li> [ryddler] ([http://cmi.pm.org|cmi.pm])
<li> [kutsu]
<li> [bobf]
<li> [perlfan]
</ul>
<p>
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2011-09-23 14:11:44
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