List Commands Library for 50g

[pier4r]

(08-31-2017 11:53 PM)DavidM Wrote:  What to do about duplicates in the result list (if anything) is entirely dependent on the problem itself, and should not be assumed by the internals of DOCOMB. Same applies to DOPERM. Depending on the problem, those duplicates may actually be exactly what you are looking for.

Yeah that's a good point. Fortunately your great library as LDDUP so no problem.

I am not sure you checked it but I'd like to know if you would have done the program here (that is using your library a lot) http://www.hpmuseum.org/forum/thread-892...l#pid78250 differently.

I paste it here

Code:

OEISA014261
  @see www.hpmuseum.org/forum/thread-8928.html
  @in practice we should generate all the positive integers not containing
  @even digits.
  @Those small challenegs are nice because are not overwhelming and still can be
  @approached in many ways.
  
  @listExt of DavidM
  @LSORT from hpcalc
  \<<
    @Input: N
    @Output: Nth number in the sequence.
  
    @Plan
    @ combining digits 1 3 5 7 9 in increasing way.
    
    @so making heavy use of the awesome list library of david.
    @I can just generate tuples and sort them.
    
    { 1 3 5 7 9 } "baseList" DROP
    { } "currentIterBaseList" DROP
    {} "currentIterationList" DROP
    1 "digitsInIteration" DROP
    0 "mthGeneratedNumber" DROP
    0 "skippedNumbers" DROP
    
    \->
    @input
    valueN
    
    @local var
    baseList
    currentIterBaseList
    currentIterationList
    digitsInIteration
    mthGeneratedNumber
    skippedNumbers
    \<<
      IF
        valueN 1 > NOT
      THEN
        0
      ELSE
        WHILE
          valueN 5 digitsInIteration ^
          >
        REPEAT
          'skippedNumbers' 5 digitsInIteration ^ STO+
          'digitsInIteration' 1 STO+
        END

        @generate a source list with enough digits 
        @(small limits of the current version of the list library of davidM)
        @in general to generate 111 we need 3 "1" in the list, so
        baseList digitsInIteration LMRPT 'currentIterBaseList' STO
          @can we use sorted? so we have the numbers generated in order?
          @nu. Generating a list from sorted input list and then removing duplicates
          @does not help. This may be a request for another command similar to DOPERM
        
        @generate all the permutations of the elements, turn them in numbers
        @clear the equal ones
        currentIterBaseList digitsInIteration 
        \<< NL\->I \>> 
        DOPERM
        LDDUP
        :2:LSORT EVAL
        
        @then we pick the right element
        valueN skippedNumbers -
        GET
      END
    \>>
  \>>

My point is that with DOPERM (the implementation is really neat, with flags to kill the process) I nevertheless have to produce all the permutations with X digits, then remove the duplicates and then sort them to pick the right element.

I was not able to devise a way to create permutations already "sorted" somehow. If I would be able to do that, I could quit in the middle of the process with the right element.