Boolean Array in Julia

New to Julia
1

Hi guys,
I’m trying to translate this code into Julia. I was wondering the best way to do this:

BOOLEAN ARRAY PerfectConsonance[0:12];
SIMPLE PROCEDURE PerfInit;
  BEGIN
  PerfectConsonance[Unison]:=TRUE;
  PerfectConsonance[Fifth]:=TRUE;
  PerfectConsonance[Octave]:=TRUE;
  END; REQUIRE PerfInit INITIALIZATION;

Thanks,
Nakul

2

It will be easier to help you if you can explain what your code is trying to do (and what language it’s written in). It looks like it might be SAIL, a dialect of ALGOL (according to some frantic googling)?

2 Likes
3

Your area of work is not an expertise of mine. Nonetheless…

module Consonance

export PerfectConsonance,
      Unison, MinorSecond, MajorSecond,
      Fifth, Octave

#=
 Julia uses 1-based indexing, so the first
 index into a vector is `1` and the last
 index in a vector of length 13 is `13`.
 To use named musical intervals' semitone
 counts as indices, add 1 to each count.
=#

const Unison      =  0 + 1
const MinorSecond =  1 + 1
const MajorSecond =  2 + 1
# ...
const Fifth       =  7 + 1
const Octave      = 12 + 1

#=
  const Vec = [ ..values.. ] 
  means the assignment of the name Vec does not
  change.  The specific values Vec contains are
  alterable and we use this to set up a vector
  of 13 Boolean values, preinitialized false,
  and then initialized for use elsewhere.
=#

const PerfectConsonance = falses(13)

#=
  now assign `true` to each that is perfect
  `=` is used when assigning one thing to another
  `.=` is used when assigning one thing to others
=# 
PerfectConsonance[[Unison, Fifth, Octave]] .= true

end # module Consonance

#=
  `using ModuleName` works with externally stored packages
  `using .ModuleName` works with modules written interactively
      and also is used when one module contains another.
=#

using .Consonance

PerfectConsonance[Fifth]
# true

PerfectConsonance[MinorSecond]
# false
1 Like
4

Thank you very much for the explanation. const in conjunction with the preinitialized falses/trues is a very interesting concept.

It is code for counterpoint music generation. I just discovered that the SAIL code was also ported to C in the same GitHub. metasolfeggio/classics at master · namin/metasolfeggio · GitHub

The equivalent Boolean interpretation in C is yet another way to do it.

int PerfectConsonance[13] =   {1,0,0,0,0,0,0,1,0,0,0,0,1};
int ImperfectConsonance[13] = {0,0,0,1,1,0,0,0,1,1,0,0,0};
int Dissonance[13] =          {0,1,1,0,0,1,1,0,0,0,1,1,0};