chord/add-harmonics [ Methods ]
DESCRIPTION
Adds pitches to the set which are harmonically related to the existing pitches. The keywords are the same as for the get-harmonics function. See also sc-set method of the same name and get-pitch-list-harmonics. NB This will automatically sort all pitches from high to low.
ARGUMENTS
- a chord object
OPTIONAL ARGUMENTS
keyword arguments: see get-harmonics function
RETURN VALUE
the same set object as the first argument but with new pitches added.
SYNOPSIS
(defmethod add-harmonics ((c chord) &rest keywords)
chord/add-mark [ Methods ]
DESCRIPTION
Add the specified mark to the MARKS slot of the given chord object.
ARGUMENTS
- A chord object. - A mark.
OPTIONAL ARGUMENTS
- T or NIL to indicate whether to print a warning when attempting to add a mark to a rest.
RETURN VALUE
Returns the full contents of the MARKS slot of the given chord object
EXAMPLE
;;; Returns the complete contents of the MARKS slot (let ((chrd (make-chord '(cs4 e4 fs4 af4 bf4)))) (add-mark chrd 'fff) (add-mark chrd 'pizz)) => (PIZZ FFF)
SYNOPSIS
(defmethod add-mark ((c chord) mark &optional warn-rest warn-again)
chord/add-pitches [ Methods ]
DESCRIPTION
Add the specified pitches to the given chord object. This can include duplicate pitches for things like violin fingered and open string unisons. If you don't want pitch duplications, call the rm-duplicates method after calling this method.
ARGUMENTS
- A chord object. - The pitches to add to that object. These can be pitch objects or any data that can be passed to make-pitch, or indeed lists of these, as they will be flattened.
RETURN VALUE
- A chord object.
EXAMPLE
(let ((ch (make-chord '(c4 e4 g4)))) (print (get-pitch-symbols ch)) (add-pitches ch 'bf3) (print (get-pitch-symbols ch)) (add-pitches ch 'af3 'a4 'b4) (print (get-pitch-symbols ch)) (add-pitches ch '(cs5 ds5 fs5)) (print (get-pitch-symbols ch))) => (C4 E4 G4) (BF3 C4 E4 G4) (AF3 BF3 C4 E4 G4 A4 B4) (AF3 BF3 C4 E4 G4 A4 B4 CS5 DS5 FS5)
SYNOPSIS
(defmethod add-pitches ((c chord) &rest pitches)
chord/artificial-harmonic-simple? [ Methods ]
DATE
January 10th 2019, Heidhausen
DESCRIPTION
Tests a chord to see if it's an artificial harmonic such as that created by force-artificial-harmonic. Unlike artificial-harmonic? this looks for two-note chords, the second of which has the flag-head marks and is a fourth away i.e. this is the simplest double-octave type.
ARGUMENTS
- a chord object
RETURN VALUE
T or NIL
SYNOPSIS
(defmethod artificial-harmonic-simple? ((c chord))
chord/artificial-harmonic? [ Methods ]
DATE
October 4th 2014
DESCRIPTION
Determine whether a chord represents an artificial harmonic of the type that strings play. An artificial harmonic here is defined as a three note chord where the second note has a 'flag-head mark (i.e diamond shape) and the 1st and 3rd are related in frequency by an integer ratio. NB What we don't do (yet) is test whether the 2nd note is the correct nodal point to produce the given pitch.
ARGUMENTS
- a chord object
OPTIONAL ARGUMENTS
- cents-tolerance: how many cents the top note can deviate from a pure partial frequency. E.g. the 7th harmonic is about 31 cents from the nearest tempered note.
RETURN VALUE
If the chord is an artificial harmonic then the sounding (3rd) note is returned, otherwise NIL.
SYNOPSIS
(defmethod artificial-harmonic? ((c chord) &optional (cents-tolerance 31))
chord/calculate-dissonance [ Methods ]
DATE
27th July 2015, Edinburgh
DESCRIPTION
Calculates the dissonance of a chord as it would appear when played on the piano (by default; other instruments' spectral data can also be used: see below). This uses a roughness calculation model by Pantelis N. Vassilakis as outlined at http://www.acousticslab.org/learnmoresra/moremodel.html. The model has been perceptually verified. We use spectral data handled by spectra.lsp to sum the roughness of sine pairs up to the first 12 partials of each tone, i.e. every partial of every tone is calculated in relation to all other tones' partials, taking their amplitudes into account. NB If notes are above/below the piano range for which we have data then we use the highest/lowest spectral data available. NB This method will be called automatically the first time you access a chord object's dissonance slot. In that case the default keyword arguments will be used. If you want to use different arguments or recalculate dissonance after the chord has been altered, this method can be used at any time but bear in mind that it does automatically change the dissonance slot so use with caution. If you merely want to change the default spectra which are used, then you can do that at startup via (set-sc-config 'default-spectra ...). You can also call rm-diss-cen to delete centroid and dissonance slot values (this exists in the set-palette class too).
ARGUMENTS
- the chord object
OPTIONAL ARGUMENTS
keyword arguments: - :num-partials. The number of partials we want to use in our calculation. Default = 12. - :average. T or NIL to indicate whether we want to use the average spectrum for an octave with the current note of a chord in the middle. Default = T. - :spectrum. Pass a two-element list of partial frequency scalers (list) and amplitudes (list) to use instead of the piano data. The amplitudes should be normalised from 0.0 to 1.0 and there should be as many of these as frequency scalers and :num-partials. Bear in mind that even using the same data for several calls, this will still give different results for the same chord type starting on different notes, as the perceptual dissonance is based on pitch height as well as interval structure. Default = (get-sc-config 'default-spectra) (see globals.lsp)
RETURN VALUE
A floating point number representing the dissonance value. Higher values are more dissonant.
EXAMPLE
(loop for chord in '((c4 e4 g4) (d4 fs4 a4) (c4 ef4 g4) (c2 e2 g2) (c3 e3 g3) (c4 e4 g4 b4) (c4 e4 g4 b4 cs4)) collect (calculate-dissonance (make-chord chord) :num-partials 12)) --> (0.402377778595695d0 0.3699311905936456d0 0.4174836004632471d0 1.8766497834038562d0 1.0522737914732592d0 0.7389679913974341d0 1.59662137873394d0)
SYNOPSIS
(defmethod calculate-dissonance ((c chord) &key (num-partials 12) (average t) (spectrum (get-sc-config 'default-spectra)))
chord/calculate-spectral-centroid [ Methods ]
DATE
July 28th 2015
DESCRIPTION
Calculate the spectral centroid of a chord. This technique is of course usually applied in digital signal processing to an audio signal via a Fast Fourier Transform (FFT). It's perhaps a little strange to use this on pitch data, not least of which because we will not be taking into account any phase information or interference of possible harmonic partial interactions, but nevertheless we get a good indication of the "pitch height" of a chord via this method. NB This will be called automatically the first time you access a chord object's centroid slot. In that case the default keyword arguments will be used. If you want to use different arguments or recalculate the centroid after the chord has been altered, this method can be used at any time but bear in mind that it does automatically change the centroid slot so use with caution. You can call rm-diss-cen to delete centroid and dissonance slot values (this exists in the set-palette class too).
ARGUMENTS
- the chord object
OPTIONAL ARGUMENTS
keyword arguments: - :num-partials. The number of partials we want to use in our calculation. Default = 12. - :average. T or NIL to indicate whether we want to use the average spectrum for an octave with the current note of a chord in the middle. Default = T. - :spectrum. Pass a two-element list of partial frequency scalers (list) and amplitudes (list) to use instead of the piano data. The amplitudes should be normalised from 0.0 to 1.0 and there should be as many of these as frequency scalers and :num-partials. Default = (get-sc-config 'default-spectra) (see globals.lsp)
RETURN VALUE
A floating point value representing the frequency in Hertz of the spectral centroid.
EXAMPLE
(calculate-spectral-centroid (make-chord '(fs3 c4 cs4 d4 ds4 e4))) --> 692.3215865354373d0 (calculate-spectral-centroid (make-chord '(fs3 c4 cs4 d4 ds4 e4 g6))) --> 772.4924013974714d0
SYNOPSIS
(defmethod calculate-spectral-centroid ((c chord) &key (num-partials 12) (average t) (spectrum (get-sc-config 'default-spectra)))
chord/chord-equal [ Methods ]
DESCRIPTION
Test to see if two chords are equal. NB: Two unsorted chord objects that contain the exact same pitch objects in a different order will not be considered equal and will return NIL. NB: Equality is tested on pitch content only, not on, for example, the values of the MIDI slots of those pitch objects etc.
ARGUMENTS
- A first chord object. - A second chord object.
RETURN VALUE
T or NIL. T if the pitch content of the chords is equal, otherwise NIL.
EXAMPLE
;; Two chords are equal (let ((chrd1 (make-chord '(c4 e4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12)) (chrd2 (make-chord '(c4 e4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12))) (chord-equal chrd1 chrd2)) => T ;; Chord objects with the same pitch objects in a different order are unequal (let ((chrd1 (make-chord '(c4 e4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12)) (chrd2 (make-chord '(e4 c4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12 :auto-sort nil))) (chord-equal chrd1 chrd2)) => NIL ;; Only the pitch content is compared. Content of other slots is irrelevant. (let ((chrd1 (make-chord '(e4 c4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12)) (chrd2 (make-chord '(e4 c4 gqs4 bqf4 d5 f5) :midi-channel 7 :microtones-midi-channel 8))) (chord-equal chrd1 chrd2)) => T
SYNOPSIS
(defmethod chord-equal ((c1 chord) (c2 chord))
chord/chord-member [ Methods ]
DESCRIPTION
Test whether a specified pitch object is a member of a given chord object.
ARGUMENTS
- A chord object. - A pitch object. This must be a pitch object, not just a note-name symbol, but the pitch object can be made with either a note-name symbol or a numerical hertz frequency value.
OPTIONAL ARGUMENTS
- T or NIL to indicate whether or not the method should consider enharmonically equivalent pitches to be equal. T = enharmonics are equal. Default = T.
RETURN VALUE
Similar to Lisp's "member" function, this method returns the tail of the data (list of pitch objects) of the tested chord object starting with the specified pitch object if that pitch is indeed a member of that list, otherwise returns NIL. NB: Since the method returns the tail of the given chord (the "rest" of the pitches after the given pitch), the result may be different depending on whether that chord has been auto-sorted or not.
EXAMPLE
;; Returns the tail of pitch objects contained starting with the tested pitch (let ((chrd (make-chord '(c4 e4 gqs4 a4 d5 f5 bqf5) :midi-channel 11 :microtones-midi-channel 12))) (pitch-list-to-symbols (chord-member chrd (make-pitch 'a4)))) => (A4 D5 F5 BQF5) ;; The chord object's default auto-sort feature might appear to affect outcome (let ((chrd (make-chord '(d5 c4 gqs4 a4 bqf5 f5 e4) :midi-channel 11 :microtones-midi-channel 12))) (pitch-list-to-symbols (chord-member chrd (make-pitch 'a4)))) => (A4 D5 F5 BQF5) ;; Returns NIL if the pitch is not present in the tested chord object. This ;; example uses the "pitch-list-to-symbols" function to simplify the ;; pitch-object output. (let ((chrd (make-chord '(d5 c4 gqs4 a4 bqf5 f5 e4) :midi-channel 11 :microtones-midi-channel 12))) (pitch-list-to-symbols (chord-member chrd (make-pitch 'b4)))) => NIL ;; The optional <enharmonics-are-equal> argument is set to NIL by default (let ((chrd (make-chord '(c4 e4 a4 d5 f5)))) (pitch-list-to-symbols (chord-member chrd (make-pitch 'ds4)))) => NIL ;; Setting the optional <enharmonics-are-equal> argument to T (let ((chrd (make-chord '(c4 ef4 a4 d5 f5)))) (pitch-list-to-symbols (chord-member chrd (make-pitch 'ds4) t))) => (EF4 A4 D5 F5) ;; The optional <octaves-are-true> argument is NIL by default (let ((chrd (make-chord '(c4 ef4 a4 d5 ef5 f5)))) (pitch-list-to-symbols (chord-member chrd (make-pitch 'c5)))) => NIL ;; If optional <octaves-are-true> argument is set to T, any occurrence of the ;; same pitch class in a different octave will be considered part of the chord ;; and return a positive result. (let ((chrd (make-chord '(c4 ef4 a4 d5 ef5 f5)))) (pitch-list-to-symbols (chord-member chrd (make-pitch 'c5) nil t))) => (C4 EF4 A4 D5 EF5 F5)
SYNOPSIS
(defmethod chord-member ((c chord) (p pitch) &optional (enharmonics-are-equal t) (octaves-are-true nil))
chord/chord= [ Methods ]
DATE
November 11th 2013
DESCRIPTION
Test whether the pitch objects of the two chords are pitch=. Assumes both chords are sorted by pitch height. See pitch= in the pitch class for details of comparing pitches.
RETURN VALUE
T or NIL
SYNOPSIS
(defmethod chord= ((c1 chord) (c2 chord) &optional enharmonics-are-equal (frequency-tolerance 0.01)) ; (src-tolerance 0.0001))
chord/collapse [ Methods ]
DATE
February 1st 2018, Heidhausen
DESCRIPTION
Collapse or shift all the pitches of a chord until a single octave.
ARGUMENTS
- a chord object - the octave to shift the pitches into (integer)
OPTIONAL ARGUMENTS
none
RETURN VALUE
a new chord object with the pitches in the given object
EXAMPLE
(print-simple (collapse (make-chord '(d4 f4 bf4 e5 b5)) 2)) --> NIL: D2 E2 F2 BF2 B2
SYNOPSIS
(defmethod collapse ((c chord) octave)
chord/common-notes [ Methods ]
DESCRIPTION
Return the integer number of pitches common to two chord objects.
ARGUMENTS
- A first chord object. - A second chord object.
OPTIONAL ARGUMENTS
- T or NIL to indicate whether enharmonically equivalent pitches are to be considered the same pitch. T = enharmonically equivalent pitches are considered the same pitch. Default = T. - T or NIL to indicate whether the same pitch class in different octaves is to be considered the same pitch. T = consider the same pitch class from octaves to be the same pitch. Default = NIL.
RETURN VALUE
Returns an integer that is the number of pitches common to the two chords objects. Two further values are returned: the list of common pitches and a list of their pitch symbols.
EXAMPLE
;; The following two chord objects have 3 pitches in common (let ((chrd-1 (make-chord '(c4 e4 g4 b4 d5 f5))) (chrd-2 (make-chord '(d3 f3 a3 c4 e4 g4)))) (common-notes chrd-1 chrd-2)) => 3 ;; By default, enharmonically equivalent pitches are considered to be the same ;; pitch (let ((chrd-1 (make-chord '(c4 e4 g4 b4 d5 f5))) (chrd-2 (make-chord '(d3 f3 a3 c4 ff4 g4)))) (common-notes chrd-1 chrd-2)) => 3 ;; Setting the first optional argument to NIL causes enharmonically equivalent ;; pitches to be considered separate pitches (let ((chrd-1 (make-chord '(c4 e4 g4 b4 d5 f5))) (chrd-2 (make-chord '(d3 f3 a3 c4 ff4 g4)))) (common-notes chrd-1 chrd-2 nil)) => 2 ;; By default, the same pitch class in different octaves is considered to be a ;; separate pitch (let ((chrd-1 (make-chord '(c4 e4 g4 b4 d5 f5))) (chrd-2 (make-chord '(d3 f3 a3 ff4 g4 c5)))) (common-notes chrd-1 chrd-2 t)) => 2 ;; Setting the second optional argument to T causes all pitches of the same ;; pitch class to be considered equal regardless of their octave (let ((chrd-1 (make-chord '(c4 e4 g4 b4 d5 f5))) (chrd-2 (make-chord '(d3 f3 a3 ff4 g4 c5)))) (common-notes chrd-1 chrd-2 t t)) => 5
SYNOPSIS
(defmethod common-notes ((c1 chord) (c2 chord) &optional (enharmonics-are-equal t) (octaves-are-true nil))
chord/contains-pitches [ Methods ]
DESCRIPTION
Check to see if a given chord object contains pitch objects for all of the specified note-names. The method returns NIL if any one of the specified pitches is not found in the given chord object.
ARGUMENTS
- An chord object. - A list of note-name symbols or pitch objects. NB: If checking for only one pitch, that pitch must be passed as a single-item list.
RETURN VALUE
T or NIL.
EXAMPLE
;; Returns T when all specified pitches are contained in the given chord ;; object (let ((c (make-chord '(d2 f2 a2 c3 e3 g3 b3 d4 gf4 bf4 df5 f5 af5 c6)))) (contains-pitches c '(d2 e3 gf4 af5))) => T ;; Returns NIL if any one of the specified pitches is not contained in the ;; given chord object. (let ((c (make-chord '(d2 f2 a2 c3 e3 g3 b3 d4 gf4 bf4 df5 f5 af5 c6)))) (contains-pitches c '(d2 e3 gf4 b4 af5))) => NIL
SYNOPSIS
(defmethod contains-pitches ((c chord) pitches &optional enharmonics-are-equal octaves-are-true)
chord/delete-marks [ Methods ]
DESCRIPTION
Delete all marks from the MARKS slot of the given chord object.
ARGUMENTS
- A chord object.
RETURN VALUE
Returns NIL.
EXAMPLE
;;; Make a chord object, add two marks, and print the MARKS slot to see them; ;;; apply delete-marks and print the MARKS slot again to see the change (let ((chrd (make-chord '(cs4 e4 fs4 af4 bf4)))) (add-mark chrd 'fff) (add-mark chrd 'pizz) (print (marks chrd)) (delete-marks chrd) (print (marks chrd))) => (PIZZ FFF) NIL
SYNOPSIS
(defmethod delete-marks ((c chord))
chord/get-highest [ Methods ]
DATE
28/10/14
DESCRIPTION
Assuming the auto-sort slot is T (which it is by default), return the last (= highest) pitch in the chord.
ARGUMENTS
- a chord object
RETURN VALUE
The highest pitch (object) in the chord.
SYNOPSIS
(defmethod get-highest ((c chord))
chord/get-interval-structure [ Methods ]
DESCRIPTION
Get the distances between each pitch in a given sc-set object and the lowest (or neighbouring) pitch in that object in DEGREES (which default to quarter-tones in slippery chicken). This method assumes that the given sc-set object is sorted from low to high, which is the default action for sc-set objects.
ARGUMENTS
- An sc-set object. OPTIONAL - T or NIL indicating whether to return values in semitones or default of degrees. Special case: if this argument is 'frequencies, then the interval structure will be returned as frequency differences. T = semitones. Default = NIL. - T or NIL to indicated whether we should return intervals from pitch to pitch (T) or from the lowest to each pitch (NIL). Default = NIL.
RETURN VALUE
A list of integers.
EXAMPLE
;;; Returns the distances in degrees (which are quarter-tones by default ;;; in slippery chicken--use (in-scale :chromatic) at the top of your code to ;;; set to the chromatic scale): (get-interval-structure (make-chord '(c4 e4 g4))) -> (8.0 14.0) ;;; Return semitones (get-interval-structure (make-chord '(c4 e4 g4)) t) -> (4.0 7.0) ;;; Interval structure not from lowest but from pitch to pitch (ascending) (get-interval-structure (make-chord '(c4 e4 g4 b4)) t t) ->(4.0 3.0 4.0)
SYNOPSIS
(defmethod get-interval-structure ((c chord) &optional in-semitones neighbour)
chord/get-midi-channel [ Methods ]
DESCRIPTION
Get the MIDI channel of the first pitch object contained in a given chord object. NB: This method returns only the midi-channel of the first pitch object in the chord object's data list.
ARGUMENTS
- A chord object.
RETURN VALUE
An integer: the midi channel
EXAMPLE
(let ((chrd (make-chord '(c4 e4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12))) (get-midi-channel chrd)) => 11
SYNOPSIS
(defmethod get-midi-channel ((c chord))
chord/get-partials-amps [ Methods ]
DATE
July 28th 2015, Edinburgh
DESCRIPTION
Return a list containing for every pitch in the chord a list of two lists: first the partial frequency scalars (which will be integers or very close to integers) then the normalised partial amplitudes. Note that if spectrum are given then average is ignored. If spectrum is an assoc-list then we get the data from it otherwise if it's just a list of freq-scalers then amps, it's fixed and we use that repeatedly.
ARGUMENTS
- the chord object
OPTIONAL ARGUMENTS
keyword arguments: - :average. Whether to average spectral data over one octave centring around each of the pictures in the chord. Default = T. - :spectrum. The spectrum data. Default = (get-sc-config 'default-spectra) (see globals.lsp)
RETURN VALUE
A list of two element sublist. of numbers.
EXAMPLE
(get-partials-amps (make-chord '(c4 e4 g4))) --> (((0.99666667 1.9958333 2.9941666 3.9958336 5.002501 6.015 7.0333333 8.049168 9.086666 10.125 11.174167 12.234166) (0.9447856 1.0000001 0.22975834 0.13516104 0.1625952 0.05319352 0.12118169 2.1978654e-4 0.049031425 0.010756988 0.011732774 0.0)) ((0.9966666 1.9958333 2.9966667 4.0025005 5.0133333 6.028333 7.0575004 8.085834 9.136668 10.193334 11.264999 12.346667) (0.99999994 0.73724264 0.20146085 0.10752921 0.122650035 0.03613218 0.06638182 0.0 0.022111647 0.004390597 0.011441806 5.167861e-4)) ((0.9966666 1.995 3.0 4.005834 5.0208335 6.042501 7.08 8.1225 9.185 10.261666 11.45 11.405833) (1.0 0.48279247 0.1664997 0.066108614 0.07859015 0.027295936 0.035848983 0.0 0.010107763 0.0027390774 0.0040924386 0.0010194636)))
SYNOPSIS
(defmethod get-partials-amps ((c chord) &key (average t) (spectrum (get-sc-config 'default-spectra)))
chord/get-pitch [ Methods ]
DESCRIPTION
Get the pitch object located at the specified index within the given chord object. The <ref> argument is 1-based.
ARGUMENTS
- A chord object. - An integer that is the index of the pitch object sought within the data list of the given chord object.
RETURN VALUE
A pitch object.
EXAMPLE
(let ((chrd (make-chord '(c4 e4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12))) (get-pitch chrd 3)) => PITCH: frequency: 403.482, midi-note: 67, midi-channel: 12 pitch-bend: 0.5 degree: 135, data-consistent: T, white-note: G4 nearest-chromatic: G4 src: 1.5422108173370361, src-ref-pitch: C4, score-note: GS4 qtr-sharp: 1, qtr-flat: NIL, qtr-tone: 1, micro-tone: T, sharp: NIL, flat: NIL, natural: NIL, octave: 4, c5ths: 0, no-8ve: GQS, no-8ve-no-acc: G show-accidental: T, white-degree: 32, accidental: QS, accidental-in-parentheses: NIL, marks: NIL LINKED-NAMED-OBJECT: previous: NIL, this: NIL, next: NIL NAMED-OBJECT: id: GQS4, tag: NIL, data: GQS4
SYNOPSIS
(defmethod get-pitch ((c chord) ref)
chord/get-pitch-symbols [ Methods ]
DESCRIPTION
Return the data of the pitch objects from a given chord object as a list of note-name symbols.
ARGUMENTS
- A chord object.
RETURN VALUE
A list of note-name symbols.
EXAMPLE
(let ((chrd (make-chord '(c4 e4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12))) (get-pitch-symbols chrd)) => (C4 E4 GQS4 BQF4 D5 F5)
SYNOPSIS
(defmethod get-pitch-symbols ((c chord) &optional ignore)
chord/has-notes [ Methods ]
DATE
16-Aug-2010
DESCRIPTION
Tests whether a given chord object contains at least one pitch object. (make-chord nil) is a valid function call and creates a chord object with no notes.
ARGUMENTS
- A chord object.
RETURN VALUE
Returns T if the given chord object contains at least one pitch object, otherwise returns NIL.
EXAMPLE
;; Returns T if the given chord object contains at least one pitch object (let ((chrd (make-chord '(c4)))) (has-notes chrd)) => T (let ((chrd (make-chord '(c4 e4 g4)))) (has-notes chrd)) => T ;; Otherwise returns NIL (let ((chrd (make-chord nil))) (has-notes chrd)) => NIL
SYNOPSIS
(defmethod has-notes ((c chord))
chord/highest [ Methods ]
DESCRIPTION
Return the pitch object from the given chord object that has the highest pitch data. NB: As opposed to the "lowest" method, this method cannot handle chord objects whose pitches have not been auto-sorted from low to high.
ARGUMENTS
- A chord object.
RETURN VALUE
A pitch object
EXAMPLE
;; Returns the last pitch object of a chord object (let ((chrd (make-chord '(e4 c4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12))) (highest chrd)) => PITCH: frequency: 698.456, midi-note: 77, midi-channel: 11 pitch-bend: 0.0 degree: 154, data-consistent: T, white-note: F5 nearest-chromatic: F5 src: 2.669679641723633, src-ref-pitch: C4, score-note: F5 qtr-sharp: NIL, qtr-flat: NIL, qtr-tone: NIL, micro-tone: NIL, sharp: NIL, flat: NIL, natural: T, octave: 5, c5ths: 0, no-8ve: F, no-8ve-no-acc: F show-accidental: T, white-degree: 38, accidental: N, accidental-in-parentheses: NIL, marks: NIL LINKED-NAMED-OBJECT: previous: NIL, this: NIL, next: NIL NAMED-OBJECT: id: F5, tag: NIL, data: F5 ;; Is not capable of returning the highest pitch object from chord objects that ;; have not been auto-sorted (let ((chrd (make-chord '(e4 c4 gqs4 bqf4 f5 d5) :midi-channel 11 :microtones-midi-channel 12 :auto-sort nil))) (data (highest chrd))) => D5
SYNOPSIS
(defmethod highest ((c chord))
chord/invert [ Methods ]
DATE
May 1st 2020, Heidhaisen
DESCRIPTION
Invert the interval structure of a chord. By default the given bottom note becomes the new top note, as the intervals are mirrored around it, but if the optional argument is non-NIL then the result will be transposed so that the chord has the original range. This is quite different to the concept of traditional (tonal) chord inversion, where we move from root position to first inversion, second inversion, etc. See the trad-invert method for this.
ARGUMENTS
- a chord object
OPTIONAL ARGUMENTS
T or NIL to indicate whether the retain the original range or not
RETURN VALUE
a new chord object which is the interval inversion of the argument
EXAMPLE
(get-pitch-symbols (invert (make-chord '(d4 f4 bf4 e5 b5)))) --> (F2 C3 FS3 B3 D4) (get-pitch-symbols (invert (make-chord '(d4 f4 bf4 e5 b5)) t)) --> (D4 A4 EF5 AF5 B5)
SYNOPSIS
(defmethod invert ((c chord) &optional top-to-bottom ignore)
chord/lowest [ Methods ]
DESCRIPTION
Return the pitch object from the given chord object that has the lowest pitch data. The method can handle chord objects whose pitches have not been auto-sorted from low to high.
ARGUMENTS
- A chord object.
RETURN VALUE
A pitch object.
EXAMPLE
;; Returns the pitch object of the lowest pitch despite not being sorted (let ((chrd (make-chord '(e4 c4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12 :auto-sort nil))) (lowest chrd)) => PITCH: frequency: 261.626, midi-note: 60, midi-channel: 11 pitch-bend: 0.0 degree: 120, data-consistent: T, white-note: C4 nearest-chromatic: C4 src: 1.0, src-ref-pitch: C4, score-note: C4 qtr-sharp: NIL, qtr-flat: NIL, qtr-tone: NIL, micro-tone: NIL, sharp: NIL, flat: NIL, natural: T, octave: 4, c5ths: 0, no-8ve: C, no-8ve-no-acc: C show-accidental: T, white-degree: 28, accidental: N, accidental-in-parentheses: NIL, marks: NIL LINKED-NAMED-OBJECT: previous: NIL, this: NIL, next: NIL NAMED-OBJECT: id: C4, tag: NIL, data: C4
SYNOPSIS
(defmethod lowest ((c chord))
chord/make-chord [ Functions ]
[ Top ] [ chord ] [ Functions ]
DESCRIPTION
Create a chord object from a list of note-name symbols.
ARGUMENTS
- A list of note-name symbols or frequencies.
OPTIONAL ARGUMENTS
keyword arguments: - :id. An element of any type that is to be the ID of the chord object created. - :auto-sort. T or NIL to indicate whether the method should first sort the individual pitch objects created from low to high before returning the new chord object. T = sort. Default = T. - :midi-channel. An integer that is to be the MIDI channel value to which all of the chromatic pitch objects in the given chord object are to be set for playback. Default = 1. - :microtones-midi-channel. An integer that is to be the MIDI channel value to which all of the microtonal pitch objects in the given chord object are to be set for playback. Default = 1. NB: See player.lsp/make-player for details on microtones in MIDI output. - :force-midi-channel. T or NIL to indicate whether to force a given value to the MIDI-CHANNEL slot, even if the notes passed to the method are already pitch objects with non-zero MIDI-CHANNEL values.
RETURN VALUE
A chord object.
EXAMPLE
;; Simple usage with default values for keyword arguments (make-chord '(c4 e4 g4 b4 d5 f5)) => CHORD: auto-sort: T, marks: NIL, micro-tone: NIL SCLIST: sclist-length: 6, bounds-alert: T, copy: T LINKED-NAMED-OBJECT: previous: NIL, this: NIL, next: NIL NAMED-OBJECT: id: NIL, tag: NIL, data: ( PITCH: frequency: 261.626, midi-note: 60, midi-channel: 0 [...] data: C4 PITCH: frequency: 329.628, midi-note: 64, midi-channel: 0 [...] data: E4 [...] PITCH: frequency: 391.995, midi-note: 67, midi-channel: 0 [...] data: G4 [...] PITCH: frequency: 493.883, midi-note: 71, midi-channel: 0 [...] data: B4 [...] PITCH: frequency: 587.330, midi-note: 74, midi-channel: 0 [...] data: D5 [...] PITCH: frequency: 698.456, midi-note: 77, midi-channel: 0 [...] data: F5 ) ;; By default the pitches are first sorted low to high (let ((mc (make-chord '(e4 c4 g4 b4 f5 d5)))) (loop for p in (data mc) collect (data p))) => (C4 E4 G4 B4 D5 F5) ;; Setting the :midi-channel and :microtones-midi-channel arguments results in ;; the MIDI-CHANNEL slot of each of the contained pitch objects being set ;; accordingly, depending on whether it is a chromatic or microtonal pitch (let ((mc (make-chord '(cqs4 e4 gqf4 b4 dqf5 f5) :midi-channel 11 :microtones-midi-channel 12))) (loop for p in (data mc) collect (midi-channel p))) => (12 11 12 11 12 11)
SYNOPSIS
(defun make-chord (note-list &key (id nil) (auto-sort t) (midi-channel 1)
(microtones-midi-channel 1) (force-midi-channel t))
chord/make-chord-from-intervals [ Functions ]
[ Top ] [ chord ] [ Functions ]
DATE
May 1st 2020, Heidhausen
DESCRIPTION
Make a chord object from a starting pitch and a list of intervals in semitones.
ARGUMENTS
- the starting pitch: symbol or pitch object - the list of intervals in semitones (may be fractional if current scale is microtonal)
OPTIONAL ARGUMENTS
any keyword argument accepted by make-chord
RETURN VALUE
a chord object
EXAMPLE
(get-pitch-symbols (make-chord-from-intervals 'c4 '(6 5 7.5) :midi-channel 7)) --> (C4 FS4 B4 GQF5)
SYNOPSIS
(defun make-chord-from-intervals (start-pitch intervals &rest keyargs &key &allow-other-keys)
chord/morph [ Methods ]
DATE
May 3rd 2016, Edinburgh
DESCRIPTION
Attempt to morph between two chords by selecting some notes from each according to the amount given.
ARGUMENTS
- the first chord object - the second chord object - the amount to morph from chord 1 to 2. This should be a number between 0 and 1 where 0 would mean all chord 1, 1 would mean all chord 2 and anything else is an actual morph.
RETURN VALUE
A new chord object representing a mixture of pitches from the two chords. The length of this will depend on the relative lengths of the two chords but the minimum will be the length of the smallest chord and the maximum the length of the largest chord (in terms of number of pitches). NB If you call this method on an sc-set object the subsets and related-sets slots will be NIL (i.e. not copied over/morphed from either of the two arguments).
EXAMPLE
(print-simple (morph (make-chord '(c4 e4 g4 b4)) (make-chord '(df4 f4 af4 c5)) 0.5)) --> C4 F4 G4 C5
SYNOPSIS
(defmethod morph ((c1 chord) (c2 chord) amount)
chord/no-accidental [ Methods ]
DESCRIPTION
Set the SHOW-ACCIDENTAL slot of all pitch objects within a given chord object to NIL. This results in no accidentals for the given chord being printed when written to a score, and also excludes the writing of any accidentals for that chord in parentheses.
ARGUMENTS
- A chord object.
RETURN VALUE
Always returns NIL.
EXAMPLE
;;; Make a chord, print the SHOW-ACCIDENTAL slots of the pitch objects it ;;; contains; then call the method and print the same slots again to see the ;;; change. (let ((chrd (make-chord '(cs4 e4 fs4 af4 bf4)))) (print (loop for p in (data chrd) collect (show-accidental p))) (no-accidental chrd) (print (loop for p in (data chrd) collect (show-accidental p)))) => (T T T T T) (NIL NIL NIL NIL NIL)
SYNOPSIS
(defmethod no-accidental ((c chord))
chord/num-notes [ Methods ]
DATE
June 22nd 2019, Heidhausen
DESCRIPTION
A helper function to return the number of notes in a chord (which is merely the sclist-length slot as a chord is a child class of sclist)
ARGUMENTS
- the chord object
RETURN VALUE
an integer
SYNOPSIS
(defmethod num-notes ((c chord))
chord/output-midi-note [ Methods ]
DESCRIPTION
Generate the MIDI-related data for each pitch in a given chord object.
ARGUMENTS
- A chord object. - A number that is the start time in seconds of the given chord within the output MIDI file. - A decimal number between 0.0 and 1.0 that is the amplitude of the given chord in the output MIDI file. - A number that is the duration in seconds of the given chord in the output MIDI file.
RETURN VALUE
The corresponding data in list form.
EXAMPLE
;; Generate the MIDI-related data required for a 5-note chord that starts 100 ;; seconds into the output MIDI file, with an amplitude of 0.5 and a duration ;; of 13.0 seconds. (let ((chrd (make-chord '(cs4 e4 fs4 af4 bf4)))) (output-midi-note chrd 100.0 0.5 13.0)) => (#i(midi time 100.0 keynum 61 duration 13.0 amplitude 0.5 channel -1) #i(midi time 100.0 keynum 64 duration 13.0 amplitude 0.5 channel -1) #i(midi time 100.0 keynum 66 duration 13.0 amplitude 0.5 channel -1) #i(midi time 100.0 keynum 68 duration 13.0 amplitude 0.5 channel -1) #i(midi time 100.0 keynum 70 duration 13.0 amplitude 0.5 channel -1))
SYNOPSIS
(defmethod output-midi-note ((c chord) time amplitude duration)
chord/pitch- [ Methods ]
DESCRIPTION
Determine the difference between the lowest pitch of two chords. This method can be used, for example, to compare the written and sounding versions of a chord to determine transposition. If the lower chord is passed as the first argument, the method will return a negative number. NB: This method takes pitch bend into consideration when calculating.
ARGUMENTS
- A first chord object. - A second chord object.
RETURN VALUE
A positive or negative decimal number.
EXAMPLE
;; The method measures the distance between the first (lowest) pitches of the ;;; chord only. (let ((chrd-1 (make-chord '(c4 e4 g4))) (chrd-2 (make-chord '(d4 e4 fs4 a4)))) (pitch- chrd-2 chrd-1)) => 2.0 ;;; Passing the lower chord as the first argument produces a negative result (let ((chrd-1 (make-chord '(c4 e4 g4))) (chrd-2 (make-chord '(d4 e4 fs4 a4)))) (pitch- chrd-1 chrd-2)) => -2.0
SYNOPSIS
(defmethod pitch- ((c1 chord) (c2 chord))
chord/pitch-or-chord= [ Methods ]
AUTHOR
Daniel Ross (mr.danielross[at]gmail[dot]com)
DATE
Wed 18 Sep 2019 17:37:39 BST - London
DESCRIPTION
Convenience method, test to see if the pitch-or-chord slots of two event objects are the same. See other related methods in event.lsp
ARGUMENTS
- a pitch or chord object - a pitch or chord object
OPTIONAL ARGUMENTS
- T or NIL to indicate whether or not enharmonic pitches are considered equal. T = enharmonic pitches are considered equal. Default = NIL. - a number to indicate the frequency deviation allowed before returning NIL.
RETURN VALUE
T if the values of the two specified pitch or chord objects are equal, otherwise NIL.
EXAMPLE
;; Comparison of equal pitch objects created using note-name symbols returns T (let ((p1 (make-pitch 'c4)) (p2 (make-pitch 'c4))) (pitch-or-chord= p1 p2)) => T (let ((p1 (make-pitch 'c4)) (p2 (make-pitch 'bs3))) (pitch-or-chord= p1 p2)) => NIL (let ((p1 (make-pitch 'c4)) (p2 (make-pitch 'bs3))) (pitch-or-chord= p1 p2 t)) => T (let ((p1 (make-pitch 'c4)) (c1 (make-chord '(c4 e4 g4)))) (pitch-or-chord= p1 c1)) => NIL (let ((c1 (make-chord '(c4 e4 g4))) (c2 (make-chord '(c4 e4)))) (pitch-or-chord= c1 c2)) => NIL (let ((c1 (make-chord '(c4 e4 g4))) (c2 (make-chord '(bs4 ff4 g4)))) (pitch-or-chord= c1 c2)) => NIL (let ((c1 (make-chord '(c4 e4 g4))) (c2 (make-chord '(bs3 ff4 g4)))) (pitch-or-chord= c1 c2 t)) => T ;; Chords with only one pitch are the same as pitch object with the same pitch. (let ((c (make-chord '(c4))) (p (make-pitch 'c4))) (pitch-or-chord= c p)) => T
SYNOPSIS
(defmethod pitch-or-chord= ((c1 chord) (c2 chord) &optional enharmonics-are-equal (frequency-tolerance 0.01))
chord/respell-chord [ Methods ]
DESCRIPTION
Respell the pitches of a given chord object to improve interval structure; i.e., removing augmented intervals etc. This method respells pitches from the bottom of the chord upwards. It does not process the pitches downwards again once pitches has been changed. Instead, it reattempts the whole respelling with the enharmonic of the lowest pitch to determine which spelling produces the fewest accidentals. NB: Respelling pitches in a chord is a rather complex process and is by no means fool-proof. The process employed here is based on avoiding double accidentals; thus, since both FS4 and BS4 have single sharps, the BS4 won't be changed to C5.
ARGUMENTS
- A chord object.
OPTIONAL ARGUMENTS
- T or NIL to indicate whether to print feedback from the process to the listener. T = print. Default = NIL.
RETURN VALUE
A chord object.
EXAMPLE
(let ((chrd (make-chord '(a3 ds4 f4 fs5 c6)))) (pitch-list-to-symbols (data (respell-chord chrd t)))) => (A3 EF4 F4 GF5 C6)
SYNOPSIS
(defmethod respell-chord ((c chord) &optional verbose)
chord/rm-pitches [ Methods ]
DESCRIPTION
Remove the specified pitches from an existing chord object.
ARGUMENTS
- A chord object. - The pitches to remove from that object. These can be pitch objects or any data that can be passed to make-pitch, or indeed lists of these, as they will be flattened. NB: No warning/error will be signalled if the pitches to be removed are not actually in the chord.
RETURN VALUE
- A chord object.
EXAMPLE
(let ((ch (make-chord '(af3 bf3 c4 e4 g4 a4 b4 cs5 ds5 fs5)))) (print (get-pitch-symbols ch)) (rm-pitches ch 'bf3) (print (get-pitch-symbols ch)) (rm-pitches ch 'af3 'a4 'b4) (print (get-pitch-symbols ch)) (rm-pitches ch '(cs5 ds5 fs5)) (print (get-pitch-symbols ch))) => (AF3 BF3 C4 E4 G4 A4 B4 CS5 DS5 FS5) (AF3 C4 E4 G4 A4 B4 CS5 DS5 FS5) (C4 E4 G4 CS5 DS5 FS5) (C4 E4 G4)
SYNOPSIS
(defmethod rm-pitches ((c chord) &rest pitches)
chord/round-to-nearest [ Methods ]
DATE
October 18th 2018
DESCRIPTION
Round the pitches in the chord to the nearest pitches in the current or given scale. See the pitch class for more details.
ARGUMENTS
the chord object
OPTIONAL ARGUMENTS
keyword argument: :scale. The scale to use when rounding. (Common Music tuning object or symbol). If a symbol, then 'chromatic-scale, 'twelfth-tone, or 'quarter-tone only at present. Default is the current scale as set by (in-scale :...).
RETURN VALUE
the modified chord object
SYNOPSIS
(defmethod round-to-nearest ((c chord) &key (scale cm::*scale*))
chord/set-midi-channel [ Methods ]
DESCRIPTION
Set the MIDI channel of the pitch objects in a given chord object to the specified values.
ARGUMENTS
- A chord object. - An integer that is to be the MIDI channel for chromatic pitches in the given chord object. - An integer that is to be the MIDI channel for microtonal pitches in the given chord object. NB: See player.lsp/make-player for details on microtones in MIDI output.
RETURN VALUE
Always returns NIL.
EXAMPLE
;; Returns NIL (let ((chrd (make-chord '(c4 e4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12))) (set-midi-channel chrd 3 4)) => NIL ;; Print the value of the MIDI slot for each of the pitch objects contained in ;; the chord object before and after setting (let ((chrd (make-chord '(c4 e4 gqs4 bqf4 d5 f5) :midi-channel 11 :microtones-midi-channel 12))) (print (loop for p in (data chrd) collect (midi-channel p))) (set-midi-channel chrd 3 4) (print (loop for p in (data chrd) collect (midi-channel p)))) => (11 11 12 12 11 11) (3 3 4 4 3 3)
SYNOPSIS
(defmethod set-midi-channel ((c chord) midi-channel &optional microtones-midi-channel)
chord/similarity [ Methods ]
DATE
12th August 2015, Wals, Austria
DESCRIPTION
Calculates the similarity of two chord objects on a scale of 0.0-1.0. This weights equally the number of common notes and the interval structure between adjacent notes.
ARGUMENTS
- the first chord object - the second chord object
OPTIONAL ARGUMENTS
- T or NIL to indicate whether enharmonic notes should be treated as equal. Even when NIL, enharmonic equivalents will still score high overall, just not perfect. - T or NIL to indicate whether octave equivalents such as f#1 and f#2 should result in higher scores.
RETURN VALUE
a number between 0.0 and 1.0, with 1.0 being the same exact chord and 0.0 being two chords with no notes and no adjacent intervals in common.
EXAMPLE
(similarity (make-chord '(c4 e4 g4)) (make-chord '(c4 e4 g4))) => 1.0 (similarity (make-chord '(c4 e4 g4)) (make-chord '(df4 f4 af4))) => 0.5 (similarity (make-chord '(c1 cs1 f1 b1)) (make-chord '(d1 e1 fs1 gs1 as1))) => 0.0 (similarity (make-chord '(cs4 es4 gs4)) (make-chord '(df4 f4 af4))) => 1.0 (similarity (make-chord '(cs4 es4 gs4)) (make-chord '(df4 f4 af4)) nil) => 0.75
SYNOPSIS
(defmethod similarity ((c1 chord) (c2 chord) &optional (enharmonics-are-equal t) (octaves-are-true nil))
chord/single-pitch-chord-to-pitch [ Methods ]
AUTHOR
Daniel Ross (mr.danielross[at]gmail[dot]com)
DATE
Thu 14 Nov 2019 07:44:02 GMT London
DESCRIPTION
Turn a chord object with only one pitch in its chord slot into a pitch object.
ARGUMENTS
A chord object
OPTIONAL ARGUMENTS
NIL
RETURN VALUE
The new pitch object if the original chord contained a single pitch, otherwise the original chord object.
EXAMPLE
(data (single-pitch-chord-to-pitch (make-chord '(a4)))) => A4
SYNOPSIS
(defmethod single-pitch-chord-to-pitch ((c chord))
chord/sort-pitches [ Methods ]
DESCRIPTION
Sort the pitch objects contained within a given chord object and return them as a list of pitch objects. As an optional argument, 'ascending or 'descending can be given to indicate whether to sort from low to high or high to low.
ARGUMENTS
- A chord object.
OPTIONAL ARGUMENTS
- The symbol 'ASCENDING or 'DESCENDING to indicate whether to sort the given pitch objects from low to high or high to low. Default = 'ASCENDING.
RETURN VALUE
Returns the chord with its pitches sorted.
EXAMPLE
;; Apply the method with no optional argument (defaults to 'ASCENDING) and ;; collect and print the data of the pitch objects in the resulting list (let ((chrd (make-chord '(d5 c4 gqs4 bqf5 f5 e4) :midi-channel 11 :microtones-midi-channel 12))) (print (loop for p in (sort-pitches chrd) collect (data p)))) => (C4 E4 GQS4 D5 F5 BQF5) ;; Sort from high to low (let ((chrd (make-chord '(d5 c4 gqs4 bqf5 f5 e4) :midi-channel 11 :microtones-midi-channel 12))) (print (loop for p in (sort-pitches chrd 'descending) collect (data p)))) => (BQF5 F5 D5 GQS4 E4 C4)
SYNOPSIS
(defmethod sort-pitches ((c chord) &optional (order 'ascending))
chord/thin [ Methods ]
DATE
October 25th 2018, Heidhausen
DESCRIPTION
Reduce the number of notes in a chord. See the sc-set class method for details.
SYNOPSIS
(defmethod thin ((c chord) &key (strength 5) remove target invert)
chord/top-to-bottom [ Methods ]
DATE
May 1st 2020, Heidhausen
DESCRIPTION
Transpose a chord so that it's current top note is the new bottom note. NB This is destructive by default
ARGUMENTS
- a chord object
OPTIONAL ARGUMENTS
keywords arguments: - :destructively. Whether to modify the chord object or return a new chord. Default = T
RETURN VALUE
the modified chord object
EXAMPLE
(print-simple (top-to-bottom (make-chord '(c4 e4 g4 b4)))) --> NIL: B4 EF5 FS5 BF5
SYNOPSIS
(defmethod top-to-bottom ((c chord) &key (destructively t))
chord/transpose [ Methods ]
DESCRIPTION
Transpose the pitches of a given chord object by a specified number of semitones. The specified number can be positive or negative, and may contain a decimal segment for microtonal transposition. If passed a decimal number, the resulting note-names will be scaled to the nearest degree of the current tuning.
ARGUMENTS
- A chord object. - A positive or negative integer or decimal number indicating the number of semitones by which the pitches of the given chord object are to be transposed.
OPTIONAL ARGUMENTS
keyword arguments - :destructively. Whether to change the internal structure of the first argument or leave it unchanged, returning a new transposed chord object instead. Default = T. - :do-related-sets. T or NIL to indicate whether to transpose any contents of the RELATED-SETS slot as well. T = transpose. Default = NIL. - :lowest. Don't transpose pitches in the original chord which are lower than this argument. Default = NIL but eventually via the transpose-pitch-list function C-1 (midi note 0) - :highest. Don't transpose pitches in the original chord which are higher than this argument. Default = NIL but eventually B8 (midi note 119)
RETURN VALUE
the transposed chord object
EXAMPLE
;; Returns a chord object (let ((chrd (make-chord '(c4 e4 g4)))) (transpose chrd 3)) => CHORD: auto-sort: T, marks: NIL, micro-tone: NIL SCLIST: sclist-length: 3, bounds-alert: T, copy: T LINKED-NAMED-OBJECT: previous: NIL, this: NIL, next: NIL NAMED-OBJECT: id: NIL, tag: NIL, data: ( [...] ) ;; Accepts positive and negative integers and decimal numbers (let ((chrd (make-chord '(c4 e4 g4)))) (pitch-list-to-symbols (data (transpose chrd 3)))) => (EF4 G4 BF4) (let ((chrd (make-chord '(c4 e4 g4)))) (pitch-list-to-symbols (data (transpose chrd -3)))) => (A3 CS4 E4) (let ((chrd (make-chord '(c4 e4 g4)))) (pitch-list-to-symbols (data (transpose chrd -3.17)))) => (AQF3 CQS4 EQF4)
SYNOPSIS
(defmethod transpose ((c chord) semitones &key (destructively t) ; do-related-sets ;; MDE Tue Aug 21 19:49:47 2018 lowest highest ;; MDE Thu Mar 4 11:48:29 2021, Heidhausen (complete-error nil))
chord/wrap [ Methods ]
DATE
March 5th 2016, Edinburgh
DESCRIPTION
Take the highest pitch and wrap it around to the bottom, placing it at the same interval to the former lowest pitch as the highest pitch is to the next-to-highest pitch. Then, by default, we shift (transpose) the chord so that the next-to-highest pitch is the former highest pitch. NB If the <transpose> optional argument is T, then the lowest and highest notes of the chord will always remain the same no matter how many times this operation is performed.
ARGUMENTS
- A chord object
OPTIONAL ARGUMENTS
- the number of times to perform this operation
RETURN VALUE
The original chord object with the new pitches (clone in advance if necessary)
EXAMPLE
(get-pitch-symbols (wrap (make-chord '(c4 e4 g4 b4)))) => (C4 E4 GS4 B4) (get-pitch-symbols (wrap (make-chord '(c4 fs4 b4 f5)))) => (C4 GF4 C5 F5) (get-pitch-symbols (wrap (make-chord '(df3 c4 fs4 b4 f5)))) => (DF3 G3 FS4 C5 F5) (get-pitch-symbols (wrap (make-chord '(df3 c4 fs4 b4 f5)) 2)) => (DF3 GF3 C4 B4 F5) (get-pitch-symbols (wrap (make-chord '(d4 f4 bf4 e5 b5)) 1 nil)) => (G3 D4 F4 BF4 E5)
SYNOPSIS
(defmethod wrap ((c chord) &optional (num-times 1) (transpose t))
sclist/chord [ Classes ]
[ Top ] [ sclist ] [ Classes ]
NAME
chord File: chord.lsp Class Hierarchy: named-object -> linked-named-object -> sclist -> chord Version: 1.1.0 Project: slippery chicken (algorithmic composition) Purpose: Implementation of the chord class that is simply an sclist whose data is a list of pitch instances. Author: Michael Edwards: m@michael-edwards.org Creation date: July 28th 2001 $$ Last modified: 13:31:58 Tue Aug 27 2024 CEST SVN ID: $Id$