Skip to content

Instantly share code, notes, and snippets.

@hakank

hakank/apl1.md

Created June 4, 2011 05:20
Show Gist options
  • Star 1 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save hakank/1007613 to your computer and use it in GitHub Desktop.
Save hakank/1007613 to your computer and use it in GitHub Desktop.
Download ZIP
My APL page
Raw
apl1.md

#My APL page

My APL page at http://www.hakank.org/apl/ don't show correct APL characters on some browsers. Hopefully it works better at github. Note some hour later: Now that page seems to show the chars correct.

I tend to use Dyalog APL, and it's great dfns library (also used below).

##Some APL code Note: I'm not sure how well the special APL characters are shown in every browsers. There is an APL font (APL385.ttf) downloable from Dyalog which hopefully will give good result. Here is a direct link: Apl385.ttf

For the Project Euler problems, I have used some functions (e.g. fibonacci and factors) from the dfns library mentioned above; this may - or may not - be considering cheating.

  • Euler1:

      +/0=∧⌿3 5∘.|X/X←⍳999

  • Euler2:

      +/0=2|f/f←(4000000>f)/f←fibonacci¨⍳40

  • Euler3:

      ⌈/factors 600851475143

  • Euler4: Two versions on the same theme:

      ispalin←{(⍴t)=+/(t)=(⌽t←⍕⍵)}
  ⌈/(∊ispalin¨P)/(P←∪∊,/A∘.×A← 99+⍳900)

    1. With ispalin "expanded" as an anonymous function:

      ⌈/(∊{(⍴t)=+/(t)=(⌽t←⍕⍵)}¨P)/P←∪∊A∘.×A←99+⍳900

  • Euler 5:

      ∧/⍳20

  • Euler 6:

      ((+/s)*2)-+/(s←⍳100)*2

  • Euler 7:

      pco 10001

  • Euler 8: (Note: This don't work so well in the interactive GUI since the long line is stripped. Better to put it in a function.)

      A←'7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450'
  ⌈/×/⍎¨A[((⍳(⍴A)-4)-1)∘.+⍳5]

  • Euler 9: 1) I'm not very happy about this first version; it has too many transposes...

      ×/∊(1↑(↓c)/⍨1000=+/c←↑(b,¨{⍵*0.5}+/↑b×b←,a∘.,a←⍳500))

2) This is better, and shorter:

  ×/∊(1↑c/⍨(1000=+/¨c←b,¨{⍵*0.5}+/¨b×b←,a∘.,a←⍳500))

  • Euler 10:

    The following is a principal solution of the problem but it yields LIMIT ERROR:

      (~v∊v∘.×v)/v←1↓⍳2e6

    Using the dfn sieve

      +/sieve 2 to 2e6

Here is the recursive definition of [sieve](http://dfns.dyalog.com/n_sieve.htm)

  sieve←{ ⍝ Sieve of Eratosthenes.<br>
      ⍺←⍬ ⍝ Default no primes yet.<br>
      nxt←1↑⍵ ⍝ Next prime, and<br>
      msk←0≠nxt|⍵ ⍝ ... mask of non-multiples.<br>
      ^/1↓msk:⍺,⍵ ⍝ All non multiples - finished.<br>
     (⍺,nxt)∇ msk/⍵ ⍝ Sieve remainder.<br>
    }

##More about APL Here are some links about APL.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment