melody_metrics.py

"""
Created on Fri Oct 29 17:28:18 2022
@author: Shulei Ji
"""

from chord_metrics import tonal_centroid,halfBar_sequences
import numpy as np

TIMESIGN={0:[6, 8], 1:[4, 4], 2:[9, 8], 3:[2, 4], 4:[3, 4], 5:[2, 2], 6:[6, 4], 7:[3, 2]}
DURATION={0:2, 1:4, 2:6, 3:8, 4:10, 5:12, 6:16, 7:18, 8:20, 9:22, 10:24, 11:30, 12:32, 13:36, 14:42, 15:44, 16:48, 17:54, 18:56, 19:60,
20:64, 21:66, 22:68, 23:72, 24:78, 25:80, 26:84, 27:90, 28:92, 29:96, 30:102, 31:108, 32:120, 33:126, 34:132, 35:138, 36:144}

def compute_metrics(chord_sequence,melody_sequence):
    print(melody_sequence.count(0),melody_sequence)
    ################### PCHE & DCHE & API #######################
    pitch=[]
    pitch_class=np.array([0]*13)
    duration_class=np.array([0]*37)
    restNum=0;pitchNum=0;durationNum=0
    for i in melody_sequence:
        if i in [0,99,100,101,102,103,104,105,106]:
            continue
        if i <= 61:
            if i == 1:
                restNum+=1
                pitch.append(-1)
                pitch_class[-1]+=1
            else:
                pitch.append((i+40)%12)
                pitch_class[(i + 40) % 12]+=1
                pitchNum+=1
        else:
            duration_class[i-62] += 1
            durationNum += 1
    if pitchNum==0 and restNum==0 and durationNum==0:
        PCHE=0;DCHE=0
    else:
        pitch_class=pitch_class/(pitchNum+restNum)
        PCHE = sum([- p_i * np.log(p_i + 1e-6) for p_i in pitch_class])
        duration_class=duration_class/durationNum
        DCHE = sum([- p_i * np.log(p_i + 1e-6) for p_i in duration_class])
    intervalSum=0
    if len(pitch)==1:
        API=pitch[0]
    else:
        for i in range(len(pitch)-1):
            intervalSum+=abs(pitch[i+1]-pitch[i])
        API=intervalSum/(len(pitch)-1)
    ##########################################################
    chord_zip, melodyPit_zip, melodyDur_zip = halfBar_sequences(chord_sequence, melody_sequence)
    print(len(chord_zip), len(melodyPit_zip), len(melodyDur_zip))
    assert len(chord_zip) == len(melodyPit_zip) == len(melodyDur_zip)
    ########################## HC ############################
    HC_note_cnt=0;m_i=0
    for melodyPit_m, chord_m in zip(melodyPit_zip, chord_zip):
        #print(melodyPit_m)
        for i in range(len(melodyPit_m)):
            m = melodyPit_m[i]
            if m in chord_m:# or m==-1:
                m_i += 1
        HC_note_cnt+=len(melodyPit_m)
    HC = m_i / HC_note_cnt
    ############################# CTnCTR ############################
    c = 0
    p = 0
    n = 0
    for melodyPit_m, melodyDur_m, chord_m in zip(melodyPit_zip, melodyDur_zip, chord_zip):
        if len(chord_m) == 1:
            for ii in melodyPit_m:
                if ii != -1:
                    c += 1
            continue
        for i in range(len(melodyPit_m)):
            m = melodyPit_m[i]
            if m != -1:
                if m in chord_m:
                    c += melodyDur_m[i]
                else:
                    n += melodyDur_m[i]
                    if i + 1 < len(melodyPit_m):
                        if abs(melodyPit_m[i + 1] - melodyPit_m[i]) <= 2:
                            p += melodyDur_m[i]
    if (c + n) == 0:
        CTnCTR = 1
    else:
        CTnCTR = (c + p) / (c + n)
    ############################# PCS ############################
    score = 0
    count = 0
    for melodyPit_m, melodyDur_m, chord_m in zip(melodyPit_zip, melodyDur_zip, chord_zip):
        if len(chord_m) == 1:
            continue
        # print("melody_m: ",melody_m)
        for m in range(len(melodyPit_m)):
            if melodyPit_m[m] != -1:
                score_m = 0
                for c in chord_m:
                    # unison, maj, minor 3rd, perfect 5th, maj, minor 6,
                    if abs(melodyPit_m[m] - c) == 0 or abs(melodyPit_m[m] - c) == 3 or abs(melodyPit_m[m] - c) == 4 \
                            or abs(melodyPit_m[m] - c) == 7 or abs(melodyPit_m[m] - c) == 8 or abs(
                        melodyPit_m[m] - c) == 9 \
                            or abs(melodyPit_m[m] - c) == 5:
                        if abs(melodyPit_m[m] - c) == 5:
                            score_m += 0
                        else:
                            score_m += 1
                    else:
                        score_m += -1
                # print(m,duration_m[m])
                score += score_m * melodyDur_m[m]
                count += melodyDur_m[m]
    if count == 0:
        PCS = 1
    else:
        PCS = score / count
    ############################# MCTD ############################
    y = 0
    y_m = 0
    count = 0
    for melodyPit_m, melodyDur_m, chord_m in zip(melodyPit_zip, melodyDur_zip, chord_zip):
        if len(chord_m) == 1:
            continue
        for m in range(len(melodyPit_m)):
            if melodyPit_m[m] != -1:
                y += np.sqrt(
                    np.sum((np.asarray(tonal_centroid([melodyPit_m[m]])) - np.asarray(tonal_centroid(chord_m)))) ** 2)
                y_m += y * melodyDur_m[m]
                count += melodyDur_m[m]
    if count == 0:
        MCTD = 1
    else:
        MCTD = y / count
    return PCHE,DCHE,API,HC,CTnCTR,PCS,MCTD