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Source code for librosa.core.notation

#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""Music notation utilities"""

import re
import numpy as np
from .._cache import cache
from ..util.exceptions import ParameterError
from ..util.decorators import deprecate_positional_args

__all__ = [
    "key_to_degrees",
    "key_to_notes",
    "mela_to_degrees",
    "mela_to_svara",
    "thaat_to_degrees",
    "list_mela",
    "list_thaat",
]

THAAT_MAP = dict(
    bilaval=[0, 2, 4, 5, 7, 9, 11],
    khamaj=[0, 2, 4, 5, 7, 9, 10],
    kafi=[0, 2, 3, 5, 7, 9, 10],
    asavari=[0, 2, 3, 5, 7, 8, 10],
    bhairavi=[0, 1, 3, 5, 7, 8, 10],
    kalyan=[0, 2, 4, 6, 7, 9, 11],
    marva=[0, 1, 4, 6, 7, 9, 11],
    poorvi=[0, 1, 4, 6, 7, 8, 11],
    todi=[0, 1, 3, 6, 7, 8, 11],
    bhairav=[0, 1, 4, 5, 7, 8, 11],
)

# Enumeration will start from 1
MELAKARTA_MAP = {
    k: i
    for i, k in enumerate(
        [
            "kanakangi",
            "ratnangi",
            "ganamurthi",
            "vanaspathi",
            "manavathi",
            "tanarupi",
            "senavathi",
            "hanumathodi",
            "dhenuka",
            "natakapriya",
            "kokilapriya",
            "rupavathi",
            "gayakapriya",
            "vakulabharanam",
            "mayamalavagaula",
            "chakravakom",
            "suryakantham",
            "hatakambari",
            "jhankaradhwani",
            "natabhairavi",
            "keeravani",
            "kharaharapriya",
            "gaurimanohari",
            "varunapriya",
            "mararanjini",
            "charukesi",
            "sarasangi",
            "harikambhoji",
            "dheerasankarabharanam",
            "naganandini",
            "yagapriya",
            "ragavardhini",
            "gangeyabhushani",
            "vagadheeswari",
            "sulini",
            "chalanatta",
            "salagam",
            "jalarnavam",
            "jhalavarali",
            "navaneetham",
            "pavani",
            "raghupriya",
            "gavambodhi",
            "bhavapriya",
            "subhapanthuvarali",
            "shadvidhamargini",
            "suvarnangi",
            "divyamani",
            "dhavalambari",
            "namanarayani",
            "kamavardhini",
            "ramapriya",
            "gamanasrama",
            "viswambhari",
            "syamalangi",
            "shanmukhapriya",
            "simhendramadhyamam",
            "hemavathi",
            "dharmavathi",
            "neethimathi",
            "kanthamani",
            "rishabhapriya",
            "latangi",
            "vachaspathi",
            "mechakalyani",
            "chitrambari",
            "sucharitra",
            "jyotisvarupini",
            "dhatuvardhini",
            "nasikabhushani",
            "kosalam",
            "rasikapriya",
        ],
        1,
    )
}


[docs]def thaat_to_degrees(thaat): """Construct the svara indices (degrees) for a given thaat Parameters ---------- thaat : str The name of the thaat Returns ------- indices : np.ndarray A list of the seven svara indices (starting from 0=Sa) contained in the specified thaat See Also -------- key_to_degrees mela_to_degrees list_thaat Examples -------- >>> librosa.thaat_to_degrees('bilaval') array([ 0, 2, 4, 5, 7, 9, 11]) >>> librosa.thaat_to_degrees('todi') array([ 0, 1, 3, 6, 7, 8, 11]) """ return np.asarray(THAAT_MAP[thaat.lower()])
[docs]def mela_to_degrees(mela): """Construct the svara indices (degrees) for a given melakarta raga Parameters ---------- mela : str or int Either the name or integer index ([1, 2, ..., 72]) of the melakarta raga Returns ------- degrees : np.ndarray A list of the seven svara indices (starting from 0=Sa) contained in the specified raga See Also -------- thaat_to_degrees key_to_degrees list_mela Examples -------- Melakarta #1 (kanakangi): >>> librosa.mela_to_degrees(1) array([0, 1, 2, 5, 7, 8, 9]) Or using a name directly: >>> librosa.mela_to_degrees('kanakangi') array([0, 1, 2, 5, 7, 8, 9]) """ if isinstance(mela, str): index = MELAKARTA_MAP[mela.lower()] - 1 elif 0 < mela <= 72: index = mela - 1 else: raise ParameterError("mela={} must be in range [1, 72]".format(mela)) # always have Sa [0] degrees = [0] # Fill in Ri and Ga lower = index % 36 if 0 <= lower < 6: # Ri1, Ga1 degrees.extend([1, 2]) elif 6 <= lower < 12: # Ri1, Ga2 degrees.extend([1, 3]) elif 12 <= lower < 18: # Ri1, Ga3 degrees.extend([1, 4]) elif 18 <= lower < 24: # Ri2, Ga2 degrees.extend([2, 3]) elif 24 <= lower < 30: # Ri2, Ga3 degrees.extend([2, 4]) else: # Ri3, Ga3 degrees.extend([3, 4]) # Determine Ma if index < 36: # Ma1 degrees.append(5) else: # Ma2 degrees.append(6) # always have Pa [7] degrees.append(7) # Determine Dha and Ni upper = index % 6 if upper == 0: # Dha1, Ni1 degrees.extend([8, 9]) elif upper == 1: # Dha1, Ni2 degrees.extend([8, 10]) elif upper == 2: # Dha1, Ni3 degrees.extend([8, 11]) elif upper == 3: # Dha2, Ni2 degrees.extend([9, 10]) elif upper == 4: # Dha2, Ni3 degrees.extend([9, 11]) else: # Dha3, Ni3 degrees.extend([10, 11]) return np.array(degrees)
[docs]@deprecate_positional_args @cache(level=10) def mela_to_svara(mela, *, abbr=True, unicode=True): """Spell the Carnatic svara names for a given melakarta raga This function exists to resolve enharmonic equivalences between pitch classes: - Ri2 / Ga1 - Ri3 / Ga2 - Dha2 / Ni1 - Dha3 / Ni2 For svara outside the raga, names are chosen to preserve orderings so that all Ri precede all Ga, and all Dha precede all Ni. Parameters ---------- mela : str or int the name or numerical index of the melakarta raga abbr : bool If `True`, use single-letter svara names: S, R, G, ... If `False`, use full names: Sa, Ri, Ga, ... unicode : bool If `True`, use unicode symbols for numberings, e.g., Ri\u2081 If `False`, use low-order ASCII, e.g., Ri1. Returns ------- svara : list of strings The svara names for each of the 12 pitch classes. See Also -------- key_to_notes mela_to_degrees list_mela Examples -------- Melakarta #1 (Kanakangi) uses R1, G1, D1, N1 >>> librosa.mela_to_svara(1) ['S', 'R₁', 'G₁', 'G₂', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'N₁', 'N₂', 'N₃'] #19 (Jhankaradhwani) uses R2 and G2 so the third svara are Ri: >>> librosa.mela_to_svara(19) ['S', 'R₁', 'R₂', 'G₂', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'N₁', 'N₂', 'N₃'] #31 (Yagapriya) uses R3 and G3, so third and fourth svara are Ri: >>> librosa.mela_to_svara(31) ['S', 'R₁', 'R₂', 'R₃', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'N₁', 'N₂', 'N₃'] #34 (Vagadheeswari) uses D2 and N2, so Ni1 becomes Dha2: >>> librosa.mela_to_svara(34) ['S', 'R₁', 'R₂', 'R₃', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'D₂', 'N₂', 'N₃'] #36 (Chalanatta) uses D3 and N3, so Ni2 becomes Dha3: >>> librosa.mela_to_svara(36) ['S', 'R₁', 'R₂', 'R₃', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'D₂', 'D₃', 'N₃'] # You can also query by raga name instead of index: >>> librosa.mela_to_svara('chalanatta') ['S', 'R₁', 'R₂', 'R₃', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'D₂', 'D₃', 'N₃'] """ # The following will be constant for all ragas svara_map = [ "Sa", "Ri\u2081", None, # Ri2/Ga1 None, # Ri3/Ga2 "Ga\u2083", "Ma\u2081", "Ma\u2082", "Pa", "Dha\u2081", None, # Dha2/Ni1 None, # Dha3/Ni2 "Ni\u2083", ] if isinstance(mela, str): mela_idx = MELAKARTA_MAP[mela.lower()] - 1 elif 0 < mela <= 72: mela_idx = mela - 1 else: raise ParameterError("mela={} must be in range [1, 72]".format(mela)) # Determine Ri2/Ga1 lower = mela_idx % 36 if lower < 6: # First six will have Ri1/Ga1 svara_map[2] = "Ga\u2081" else: # All others have either Ga2/Ga3 # So we'll call this Ri2 svara_map[2] = "Ri\u2082" # Determine Ri3/Ga2 if lower < 30: # First thirty should get Ga2 svara_map[3] = "Ga\u2082" else: # Only the last six have Ri3 svara_map[3] = "Ri\u2083" upper = mela_idx % 6 # Determine Dha2/Ni1 if upper == 0: # these are the only ones with Ni1 svara_map[9] = "Ni\u2081" else: # Everyone else has Dha2 svara_map[9] = "Dha\u2082" # Determine Dha3/Ni2 if upper == 5: # This one has Dha3 svara_map[10] = "Dha\u2083" else: # Everyone else has Ni2 svara_map[10] = "Ni\u2082" if abbr: svara_map = [ s.translate(str.maketrans({"a": "", "h": "", "i": ""})) for s in svara_map ] if not unicode: svara_map = [ s.translate(str.maketrans({"\u2081": "1", "\u2082": "2", "\u2083": "3"})) for s in svara_map ] return list(svara_map)
[docs]def list_mela(): """List melakarta ragas by name and index. Melakarta raga names are transcribed from [#]_, with the exception of #45 (subhapanthuvarali). .. [#] Bhagyalekshmy, S. (1990). Ragas in Carnatic music. South Asia Books. Returns ------- mela_map : dict A dictionary mapping melakarta raga names to indices (1, 2, ..., 72) Examples -------- >>> librosa.list_mela() {'kanakangi': 1, 'ratnangi': 2, 'ganamurthi': 3, 'vanaspathi': 4, ...} See Also -------- mela_to_degrees mela_to_svara list_thaat """ return MELAKARTA_MAP.copy()
[docs]def list_thaat(): """List supported thaats by name. Returns ------- thaats : list A list of supported thaats Examples -------- >>> librosa.list_thaat() ['bilaval', 'khamaj', 'kafi', 'asavari', 'bhairavi', 'kalyan', 'marva', 'poorvi', 'todi', 'bhairav'] See Also -------- list_mela thaat_to_degrees """ return list(THAAT_MAP.keys())
[docs]@deprecate_positional_args @cache(level=10) def key_to_notes(key, *, unicode=True): """Lists all 12 note names in the chromatic scale, as spelled according to a given key (major or minor). This function exists to resolve enharmonic equivalences between different spellings for the same pitch (e.g. C♯ vs D♭), and is primarily useful when producing human-readable outputs (e.g. plotting) for pitch content. Note names are decided by the following rules: 1. If the tonic of the key has an accidental (sharp or flat), that accidental will be used consistently for all notes. 2. If the tonic does not have an accidental, accidentals will be inferred to minimize the total number used for diatonic scale degrees. 3. If there is a tie (e.g., in the case of C:maj vs A:min), sharps will be preferred. Parameters ---------- key : string Must be in the form TONIC:key. Tonic must be upper case (``CDEFGAB``), key must be lower-case (``maj`` or ``min``). Single accidentals (``b!♭`` for flat, or ``#♯`` for sharp) are supported. Examples: ``C:maj, Db:min, A♭:min``. unicode : bool If ``True`` (default), use Unicode symbols (♯𝄪♭𝄫)for accidentals. If ``False``, Unicode symbols will be mapped to low-order ASCII representations:: ♯ -> #, 𝄪 -> ##, ♭ -> b, 𝄫 -> bb Returns ------- notes : list ``notes[k]`` is the name for semitone ``k`` (starting from C) under the given key. All chromatic notes (0 through 11) are included. See Also -------- midi_to_note Examples -------- `C:maj` will use all sharps >>> librosa.key_to_notes('C:maj') ['C', 'C♯', 'D', 'D♯', 'E', 'F', 'F♯', 'G', 'G♯', 'A', 'A♯', 'B'] `A:min` has the same notes >>> librosa.key_to_notes('A:min') ['C', 'C♯', 'D', 'D♯', 'E', 'F', 'F♯', 'G', 'G♯', 'A', 'A♯', 'B'] `A♯:min` will use sharps, but spell note 0 (`C`) as `B♯` >>> librosa.key_to_notes('A#:min') ['B♯', 'C♯', 'D', 'D♯', 'E', 'E♯', 'F♯', 'G', 'G♯', 'A', 'A♯', 'B'] `G♯:maj` will use a double-sharp to spell note 7 (`G`) as `F𝄪`: >>> librosa.key_to_notes('G#:maj') ['B♯', 'C♯', 'D', 'D♯', 'E', 'E♯', 'F♯', 'F𝄪', 'G♯', 'A', 'A♯', 'B'] `F♭:min` will use double-flats >>> librosa.key_to_notes('Fb:min') ['D𝄫', 'D♭', 'E𝄫', 'E♭', 'F♭', 'F', 'G♭', 'A𝄫', 'A♭', 'B𝄫', 'B♭', 'C♭'] """ # Parse the key signature match = re.match( r"^(?P<tonic>[A-Ga-g])" r"(?P<accidental>[#♯b!♭]?)" r":(?P<scale>(maj|min)(or)?)$", key, ) if not match: raise ParameterError("Improper key format: {:s}".format(key)) pitch_map = {"C": 0, "D": 2, "E": 4, "F": 5, "G": 7, "A": 9, "B": 11} acc_map = {"#": 1, "": 0, "b": -1, "!": -1, "♯": 1, "♭": -1} tonic = match.group("tonic").upper() accidental = match.group("accidental") offset = acc_map[accidental] scale = match.group("scale")[:3].lower() # Determine major or minor major = scale == "maj" # calculate how many clockwise steps we are on CoF (== # sharps) if major: tonic_number = ((pitch_map[tonic] + offset) * 7) % 12 else: tonic_number = ((pitch_map[tonic] + offset) * 7 + 9) % 12 # Decide if using flats or sharps # Logic here is as follows: # 1. respect the given notation for the tonic. # Sharp tonics will always use sharps, likewise flats. # 2. If no accidental in the tonic, try to minimize accidentals. # 3. If there's a tie for accidentals, use sharp for major and flat for minor. if offset < 0: # use flats explicitly use_sharps = False elif offset > 0: # use sharps explicitly use_sharps = True elif 0 <= tonic_number < 6: use_sharps = True elif tonic_number > 6: use_sharps = False # Basic note sequences for simple keys notes_sharp = ["C", "C♯", "D", "D♯", "E", "F", "F♯", "G", "G♯", "A", "A♯", "B"] notes_flat = ["C", "D♭", "D", "E♭", "E", "F", "G♭", "G", "A♭", "A", "B♭", "B"] # These apply when we have >= 6 sharps sharp_corrections = [ (5, "E♯"), (0, "B♯"), (7, "F𝄪"), (2, "C𝄪"), (9, "G𝄪"), (4, "D𝄪"), (11, "A𝄪"), ] # These apply when we have >= 6 flats flat_corrections = [ (11, "C♭"), (4, "F♭"), (9, "B𝄫"), (2, "E𝄫"), (7, "A𝄫"), (0, "D𝄫"), ] # last would be (5, 'G𝄫') # Apply a mod-12 correction to distinguish B#:maj from C:maj n_sharps = tonic_number if tonic_number == 0 and tonic == "B": n_sharps = 12 if use_sharps: # This will only execute if n_sharps >= 6 for n in range(0, n_sharps - 6 + 1): index, name = sharp_corrections[n] notes_sharp[index] = name notes = notes_sharp else: n_flats = (12 - tonic_number) % 12 # This will only execute if tonic_number <= 6 for n in range(0, n_flats - 6 + 1): index, name = flat_corrections[n] notes_flat[index] = name notes = notes_flat # Finally, apply any unicode down-translation if necessary if not unicode: translations = str.maketrans({"♯": "#", "𝄪": "##", "♭": "b", "𝄫": "bb"}) notes = list(n.translate(translations) for n in notes) return notes
[docs]def key_to_degrees(key): """Construct the diatonic scale degrees for a given key. Parameters ---------- key : str Must be in the form TONIC:key. Tonic must be upper case (``CDEFGAB``), key must be lower-case (``maj`` or ``min``). Single accidentals (``b!♭`` for flat, or ``#♯`` for sharp) are supported. Examples: ``C:maj, Db:min, A♭:min``. Returns ------- degrees : np.ndarray An array containing the semitone numbers (0=C, 1=C#, ... 11=B) for each of the seven scale degrees in the given key, starting from the tonic. See Also -------- key_to_notes Examples -------- >>> librosa.key_to_degrees('C:maj') array([ 0, 2, 4, 5, 7, 9, 11]) >>> librosa.key_to_degrees('C#:maj') array([ 1, 3, 5, 6, 8, 10, 0]) >>> librosa.key_to_degrees('A:min') array([ 9, 11, 0, 2, 4, 5, 7]) """ notes = dict( maj=np.array([0, 2, 4, 5, 7, 9, 11]), min=np.array([0, 2, 3, 5, 7, 8, 10]) ) match = re.match( r"^(?P<tonic>[A-Ga-g])" r"(?P<accidental>[#♯b!♭]?)" r":(?P<scale>(maj|min)(or)?)$", key, ) if not match: raise ParameterError("Improper key format: {:s}".format(key)) pitch_map = {"C": 0, "D": 2, "E": 4, "F": 5, "G": 7, "A": 9, "B": 11} acc_map = {"#": 1, "": 0, "b": -1, "!": -1, "♯": 1, "♭": -1} tonic = match.group("tonic").upper() accidental = match.group("accidental") offset = acc_map[accidental] scale = match.group("scale")[:3].lower() return (notes[scale] + pitch_map[tonic] + offset) % 12