gistfile1.py

from constraint import Problem,\
                       RecursiveBacktrackingSolver,\
                       AllDifferentConstraint,\
                       MinConflictsSolver

import mingus.core.notes as notes
import mingus.extra.LilyPond as LilyPond
from mingus.containers import Bar,Track
from mingus.midi import MidiFileOut

from time import time # Time execution.


# Initialize our CSP problem.

AllIntervalCSP = Problem()

# Each variable is named `N#' where # is a number from 0 to 11
# This is not a requirement, but helps the eye.

NoteList = ['N'+ str(n) for n in range(0,12)]           # N0..N11


# Same for the eleven intervals.

IntervalList = ['I'+ str(i) for i in range(1,12)]       # I1..I11

# Add the variables to the csp. Each variable has a finite domain
# of integral elements that represent a pitch-class (from 0 to 11).

AllIntervalCSP.addVariables(NoteList, range(0,12))      # 0..11

AllIntervalCSP.addVariables(IntervalList, range(0, 12)) # 0..11



# Restrict every variable to take a different value.

AllIntervalCSP.addConstraint(AllDifferentConstraint(), NoteList)      # All pitches different
AllIntervalCSP.addConstraint(AllDifferentConstraint(), IntervalList)  # All intervals different


# A constraint restricts the intervals to be pair-wise distinct.
# The modulo is there because the intervals are inversional-equivalent
# (i.e. a 5th upward is an inverse fourth downward).

for i in range(1,12):
    AllIntervalCSP.addConstraint(lambda I,N1,N2: I == (N2-N1) % 12 , (IntervalList[i-1],NoteList[i-1],NoteList[i]))

# Constraint first note to be of pitch class 0 (C) and
# last note to be of pitch class L/2
    
AllIntervalCSP.addConstraint(lambda x: x==0, (NoteList[0],))     # First note is a C
AllIntervalCSP.addConstraint(lambda x: x==6, (NoteList[-1],))    # Last note is a F#/Gb

# Time while searching for a solution...

print "Searching for a solution:"
startTime = time()
AllIntervalSolution = AllIntervalCSP.getSolution()
duration = time() - startTime

if AllIntervalSolution is not None:
    print "Solution found in %.2fms." % (duration*1000.0)

    # Store the solution on a list of integers.
    
    Sol = [AllIntervalSolution[n] for n in NoteList]

    # Create a track using mingus.
    
    track = Track()
    for n in Sol:
        track.add_notes(notes.int_to_note(n))


    # Create a lilypond string from our track.
        
    lilytrack = LilyPond.from_Track(track)

    # Store it to .pdf and .png files.
    
    LilyPond.to_pdf(lilytrack, "output")
    LilyPond.to_png(lilytrack, "output")

    # Output it as a midi file.
    
    MidiFileOut.write_Track('output.mid', track, 120, 0)        
else:
    
    # Solution not found. Show time wasted.
    
    print "Solution not found. Exhausted in %ss" % duration