pcset.py

import logging
import chord
import math

class PitchClassSet:
    all_pcs = {pc for pc in range(12)}
    def __init__(self, pc_set, chords=None):
        self.logger = logging.getLogger('hakawb.PitchClassSet')
        self.logger.debug('Instantiating new pc_set {}'.format(pc_set))
        self.pc_set = pc_set
        self.name = str(set(self.pc_set))
        self.pc_set_prime = PitchClassSet.all_pcs - self.pc_set
        self.strength = 0
        self.relevance = 0
        self.activation = 0
        if chords:
            self.chords = chords
            self.logger.debug(self)
        else:
            self.chords = []

    def __str__(self):
        ret = '{}\n'.format(self.name)
        for c in self.chords:
            ret += '\t{}\n'.format(c.harmstr)
        return ret

    def add_chords(self, chords):
        if chords:
            self.chords.extend(chords)

    def strength_formula(self, heat):
        # Notes have a bit more effect on the positive contribution...
        return math.sqrt(heat)

    def relevance_formula(self, heat):
        # but a linear effect (more negative) on the negative contribution...
        return heat

    def compute_strength(self, pc_heat):
        pcs = len(self.pc_set)
        strength = []
        for i in self.pc_set:
            strength.append(self.strength_formula(pc_heat[i]))
        self.strength = sum(strength) / pcs
        return self.strength

    def compute_relevance(self, pc_heat):
        pcs_prime = len(self.pc_set_prime)
        relevance = []
        for i in self.pc_set_prime:
            relevance.append(self.relevance_formula(pc_heat[i]))
        self.relevance = 1 - (sum(relevance) / pcs_prime)
        return self.relevance

    def compute_activation(self, pc_heat):
        self.compute_strength(pc_heat)
        self.compute_relevance(pc_heat)
        self.activation = self.strength * self.relevance
        return self.activation