pwstegman/jamnetic-algorhythms

:construction: :bug: :musical_score: Using genetic algorithms to improvise over jazz standards, WIP

Jamnetic Algorhythms

Using Genetic Algorithms to improvise

Usage

Must use python 3.6 More to come

Algorithm Thoughts

• GAs for jazz standard - all of me
  • melody only tho, but maintain info about chord progressions
• Mutation = take random note in a measure, maybe for 4 random measures
  • (should we weight based on note length or nah)
  • (or maybe weight based on 'strength' of note position, i.e. notes that fall on beat 1 weighted higher than beats on & of 2)
  • 1. 0.25 probability of picking a random chord tone / note in the key?
    • maybe consider whether or not it's on strong beat
    • add any domain knowledge, or nah?
  • 2a. 0.125 probability of copying a random note already in the measure
  • 2b. 0.125 probability of transposing up/down a whole note
    • 0.5 up, 0.5 down
  • 3a. 0.25 (1 - quanta/4) probability of becoming leading note, chromatic up or down depending on beat?
    • quanta = 1 for quarter note, .5 for eighth, etc.
  • 3b. 0.25 * (quanta/4) probability of becoming split
    • 0.5 prob of even split
    • 0.25 of triplet
    • 0.25 of dotted and
      • 0.5 of short beat first
      • 0.5 of long beat first
    • apply rules 1,2,4, 7 to new notes
    • apply some min/max, where quanta turns to 0 if it's sixteenth note, also no triplet splitting
  • 4. 0.05 probability of picking note from bar with same chord progression
    • if no such bars exist, we reweight and ignore this possibility
  • 5. 0.05 probability of shifting all notes
    • 0.5 of going to right, 0.5 of going to left
  • 6. 0.05 probability of shuffling notes
    • 0.5 of just shuffling notes themselves
    • 0.5 of shuffling notes + rhythmic structure
  • 7. 0.05 probability of dropping note
  • 8. 0.05 probability of swapping notes
• Crossover ideas
  • split/join
    • Take half of bar and combine to half of other bar
    • probably better to add whole measures
    • alternate every measure?
    • take first half from one and second from other?
• reduce
  • pick pieces w/ highest fitness, leave in some wonky ones, bc "that's jazz"
• fitness function
  • dock points for no note variation
  • dock points for all notes identical to original
  • dock points for having 0 notes from chord progression
  • dock points for only having notes from chord progression
  • dock points for too many jumps
  • dock points if first note is an ugly interval off chord root (half step, 6 half steps, ignoring notes where it should belong like a maj7 / m7b5)
• Other thoughts
  • add inversions to chords
  • consider weighting everything based on quanta & 1-quanta
  • have a corpus of jazz standards to borrow phrases from
  • add different improvs of all of me to the initial population
  • dock points if duration is wonky number
  • plus points for repitition of musical phrases / rhythmic combinations?