[HN Gopher] Loda-lang - language, computational model, and OEIS ...
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       Loda-lang - language, computational model, and OEIS miner
        
       Author : todsacerdoti
       Score  : 35 points
       Date   : 2021-09-24 08:37 UTC (1 days ago)
        
 (HTM) web link (loda-lang.org)
 (TXT) w3m dump (loda-lang.org)
        
       | prezjordan wrote:
       | This is hilarious and I love it. Two questions:
       | 
       | 1) How can I see the programs that I mine? I ran mine but it's
       | unclear if I've found any?
       | 
       | 2) How can I start from the beginning? I'd like to see how long
       | it takes to mine A01, for example
        
       | tromp wrote:
       | The notion of program optimization here is rather odd, as
       | programs can refer to other programs in a single instruction. For
       | example, the program for the prime numbers is
       | seq $0,6005 ; The odd prime numbers together with 1.         max
       | $0,2
       | 
       | and if we go down the rabbit hole, we find that the program for
       | A006005 uses the instruction                   seq $0,98090 ;
       | Numbers k such that 2k-3 is prime.
       | 
       | where the A098090 program in turn uses                   seq
       | $3,10051 ; Characteristic function of primes: 1 if n is prime,
       | else 0.
       | 
       | and this pattern continues with 4 programs containing
       | instructions                   seq $1,80339 ; Characteristic
       | function of {1} union {primes}: 1 if n is 1 or a prime, else 0.
       | seq $0,38548 ; Number of divisors of n that are at most sqrt(n).
       | seq $0,94820 ; Partial sums of A038548.         seq $1,94820 ;
       | Partial sums of A038548.              seq $0,132106 ; a(n) = 1 +
       | floor(sqrt(n)) + Sum_{i=1..n} floor(n/i).
       | 
       | Where at last the program for A132106 doesn't use the seq
       | instruction.
       | 
       | There also seems to be a danger here of creating cyclic
       | definitions.
        
       | nixpulvis wrote:
       | Neat.
       | 
       | How many of the solution programs were originally hand-written vs
       | machine generated from other known solutions or actually "mined"?
       | Reading through https://github.com/loda-lang/loda-
       | cpp/blob/main/miners.defau..., it seems like the "template" for
       | each generator could have been minted one way or another. I'm a
       | little curious now...
       | 
       | It's kinda fun to see a program minimizer in ~200LoC++, but I
       | wonder what other optimization tricks would be worth implementing
       | for the purposes of integer sequence search? I wonder if it would
       | be worth wiring up a proper compiler framework? Or are there
       | other projects that already do this kind of thing faster?
       | 
       | Instead of just "matching" it might be cool to sort these
       | solutions by similarity and then compare that to the similarity
       | of the sequences themselves.
       | 
       | Finally, given that the OEIS databases exists with "FORMULA" (on
       | every entry?), wouldn't it be faster to just parse that? Maybe
       | you'd find some bugs?
        
       | tromp wrote:
       | There seems to be a problem with the mining. LODA programs are
       | described as being programs "for an OEIS sequence" when they
       | merely match in the limited number of terms given in the OEIS
       | summary, even when it obviously doesn't describe the full
       | sequence. An example is the entry for an inverse TREE function
       | [1]
       | 
       | A300402 (program): Smallest integer i such that TREE(i) >= n.
       | 
       | which is claimed to correspond to LODA program
       | min $0,4         div $0,2         add $0,1
       | 
       | [1] https://oeis.org/A300402
        
       | lain98 wrote:
       | Unfortunately named.
        
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       (page generated 2021-09-25 23:01 UTC)