The timecount() function takes a vector of rhythmic duration values and
counts (in the musical sense) the number of beats (or measures) which have occurred since the starting point,
associating each rhythmic onsets with a beat.
The subpos() function is paired with timecount(), computing how far (in rhythmic time) each onset is from its
associated beat; if subpos() returns 0, this means that an onset is on the beat.
Finally, onbeat() is simply a convenient shorthand for subpos() == 0, returning
a logical vector for indicating where onsets fall on or off beat.
Usage
# S3 method for default
timecount(
dur,
unit = rational(1L),
start = 1L,
phase = 0,
pickup = NULL,
offBeats = TRUE,
groupby = list(),
...
)
timecount(
dur,
unit = rational(1L),
start = 1L,
phase = 0,
pickup = NULL,
offBeats = TRUE,
groupby = list(),
...
)
# S3 method for default
subpos(
dur,
unit = rational(1L),
phase = 0,
pickup = NULL,
deparser = duration,
...,
groupby = list()
)
subpos(
dur,
unit = rational(1L),
phase = 0,
pickup = NULL,
deparser = duration,
...,
groupby = list()
)
# S3 method for default
onbeat(dur, unit = rational(1L), groupby = list(), ...)
onbeat(dur, unit = rational(1L), groupby = list(), ...)Arguments
- dur
An input vector of rhythmic durations.
Must be a
characterornumericvector.Is parsed using
rhythmInterval(); Wherever the input can't be parsed as a duration, that element is treated as a duration of zero.- unit
The size of "beat" (or measure) to count.
Defaults to a whole-note (one measure of 4/4 time).
Must be a
characterornumericvector, or a list of such vectors; must be a singleton or the same length asdur.Is parsed as a duration using
rhythmInterval(); If the input can't be parsed as a duration, the output will be allNA.- start
The number to start counting from.
Must be a single whole-number value (either
numericorinteger).- phase
The phase offset between onsets and beats.
Defaults to
0.Must be a
characterornumericvector; must be length1or the same length asdur; The duration ofphasemust be smaller than the smallest duration value inunit.Is parsed as a duration using
rhythmInterval(); If the input can't be parsed as a duration, an error occurs.- pickup
Indicates which leading values in the input are pickups, if any.
Defaults to
NULL.Must be
NULL, or alogicalvector of the same length asdur.- offBeats
Should off-beat onsets be numbered in the output, or
NA?Defaults to
TRUE.Must be a single
logicalvalue: an on/off switch.- groupby
Optional vectors to group by and count within.
Defaults to empty
list().Must be a
list(), which is either empty or contains vectors which are all the same length asdur. To function as a by-record timeline, thegroupbylist must include a namedPieceandRecordvectors. Luckily, these are automatically passed by with(in).humdrumR, so you won't need to worry about it!
Details
In many basic use cases, using timecount() is essentially the same as using floor(timeline()).
However, timecount() gives us a few additional options which add musicological power compared to timeline().
(timecount() also starts from 1 not 0, as timeline() does.)
The first beat in an input vector is assigned the value of the start argument, which defaults to start = 1L.
There is no 'zeroth' count, as the first beat occurs at the instant of the starting time---i.e., the first onset in the input vector.
Every rhythmic onset is associated with one beat, but multiple onsets may occur within the same beat---thus
the output of timecount() assigns (rounds) each onset to the previous beat onset.
However, if offBeats = FALSE, only onsets that land on a beat are counted, with offbeat values returning NA.
The phase controls how offbeat onsets are associated with nearby beats.
phase is parsed as a rhythmic value and must be rhythmic values that are smaller than the smallest beat value.
The phase argument shifts the "boundary" between beats backwards, before the beat onset.
By default, phase = 0 so the beat-association boundary lands on the beat: only onsets on or after each beat "belong" to that beat.
If phase = '8', the beat boundary is pushed back to capture one eighth-note before the beat itself.
This can be used to, for example, associate the last 3/8s of a measure with the next measure (like pick ups);
This could be achieved with a command like timecount(dur, beat = '1', phase = 3/8).
"Beats"
The unit argument is used to indicate what size of beat you want to count.
The default unit is a whole note, equivalent to a measure of M4/4 time.
The unit argument uses the rhythm parser, so it can understand unit values input in a variety of formats:
thus, you could specify quarter-note units as either unit = '4' or unit = 0.25.
The parser also understands how to parse the (full) duration of time signature: for example, unit = 'M3/4' would use a dotted-half-note unit ('2.').
Changing meter
If your data has changing meters (either between pieces, or within pieces), you can specify
the unit argument as a vector which is the same length as dur, indicating the
beat size at each moment/index.
This feature is very easy to use with any dataset that includes time signature interpretations, like "*M4/4";
these interpetations, if present, are automatically read into a field called TimeSignature.
For such a dataset, you can simply pass the TimeSignature field to the unit argument of timecount(), and
the measures of the piece will be correctly counted (even when changing!): timecount(x, unit = TimeSignature).
Alternatively, you can use the tactus() command to extract the tactus beat from a time signature, like timecount(x, unit = tactus(TimeSignature)).
Irregular meter
Some musical meters consist of a pattern of irregular beats.
For example, the meter M7/8 is often realized as two "short" beats (two eigth-notes each) and one "long" beat (three eigth-notes), forming a 2 + 2 + 3 pattern.
If we want to count each eighth-note, we can simply specify unit = '8' and get the M7/8 beats counted as c(1, 3, 5).
However, if we want to count each short or long beat as a single unit, we must specify the desired pattern as a list of beat durations: for example, unit = list(c("4", "4", "4.")).
Let's see what these two cases look like, applied to two M7/8 measures of straight eighth-notes:
rhythm <- rep('8', 14)
timecount(rhythm, unit = '8'),
# output is: 1 2 3 4 5 6 7 8 9 10 11 12 13 14
timecount(rhythm, unit = list(c('4', '4', '4.')))
# output is: 1 1 2 2 3 3 3 4 4 5 5 6 6 6To accommodate changing meters, the unit argument can still accept list of such patterns, so long as the list is the same length as dur.
Pickups
Another option is to pass the pickup argument a logical vector of the same length as the input dur.
Within each piece/group, any block of TRUE values at the beginning of the pickup vector
indicate a pickup.
The first index where the pickup logical is FALSE is used as the location of beat 1:
all the earlier (pickup == TRUE) points will be negative counts, counting backwards from the start.
In humdrumR, and datapoints before the first barline record (=) are labeled Bar == 0 in the Bar field.
Thus, a common use for the pickup argument is within(humData, timecount(Token, pickup = Bar < 1), which makes the downbeat of
the first complete bar 1 the stating point---any notes in pickup bars are give negative counts.
Note that there is never a 'beat zero'.
Beats before the starting point progress directly from -1 to 1 (the start).
As a result, doing arithmetic or other math with beat "counts" can be problematic when using a pickup argument.
It may be better to use round(timeline()) in cases where you want to do much math with counts.
See also
timecount() and subpos() are closely related to the timeline() function. The metcount() function applies timecount() within a metric framework.
Examples
humData <- readHumdrum(humdrumRroot, "HumdrumData/BachChorales/chor00[1-4].krn")
#> Finding and reading files...
#> REpath-pattern '/home/nat/.tmp/Rtmpn4KeFS/temp_libpath7af94615c2ed/humdrumR/HumdrumData/BachChorales/chor00[1-4].krn' matches 4 text files in 1 directory.
#> Four files read from disk.
#> Validating four files...
#> all valid.
#> Parsing four files...
#> Assembling corpus...
#> Done!
show(within(humData, timecount(Token, unit = TimeSignature, pickup = Bar < 1)))
#> ######################## vvv chor001.krn vvv #########################
#> 1: !!!COM: Bach, Johann Sebastian
#> 2: !!!CDT: 1685/02/21/-1750/07/28/
#> 3: !!!OTL@@DE: Aus meines Herzens Grunde
#> 4: !!!OTL@EN: From the Depths of My Heart
#> 5: !!!SCT: BWV 269
#> 6: !!!PC#: 1
#> 7: !!!AGN: chorale
#> 8: **kern **kern **kern **kern
#> 9: *ICvox *ICvox *ICvox *ICvox
#> 10: *Ibass *Itenor *Ialto *Isoprn
#> 11: *I"Bass *I"Tenor *I"Alto *I"Soprano
#> 12: *>[A,A,B] *>[A,A,B] *>[A,A,B] *>[A,A,B]
#> 13: *>norep[A,B] *>norep[A,B] *>norep[A,B] *>norep[A,B]
#> 14: *>A *>A *>A *>A
#> 15: *clefF4 *clefGv2 *clefG2 *clefG2
#> 16: *k[f#] *k[f#] *k[f#] *k[f#]
#> 17: *G: *G: *G: *G:
#> 18: *M3/4 *M3/4 *M3/4 *M3/4
#> 19: *MM100 *MM100 *MM100 *MM100
#> 20: -1 -1 -1 -1
#> 21: =1 =1 =1 =1
#> 22: 1 1 1 1
#> 23: 1 1 1 .
#> 24: . 1 . .
#> 25: 1 1 1 1
#> 26: =2 =2 =2 =2
#> 27: 2 2 2 2
#> 28: 2 2 . .
#> 29: . . . 2
#> 30: 2 2 2 2
#> 31: =3 =3 =3 =3
#> 32: 3 3 3 3
#> 33: . 3 3 .
#> 34: 3 3 3 .
#> 35: 3 . 3 3
#> 36: 3 3 3 3
#> 37: =4 =4 =4 =4
#> 38: 4 4 4 4
#> 39: 4 4 4 4
#> 40: =5 =5 =5 =5
#> 41: 5 5 5 5
#> 42: 5 5 5 .
#> 43: 5 5 5 5
#> 44: =6 =6 =6 =6
#> 45: 6 6 6 6
#> 46: 6 6 . 6
#> 47: 6 6 6 .
#> 48: . 6 . .
#> 49: =7 =7 =7 =7
#> 50: 7 7 7 7
#> 51-133::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
#> ######################## ^^^ chor001.krn ^^^ #########################
#>
#> (two more pieces...)
#>
#> ######################## vvv chor004.krn vvv #########################
#> 1-53::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
#> 54: 4 4 4 4
#> 55: . . 4 .
#> 56: =5 =5 =5 =5
#> 57: 5 5 5 5
#> 58: . . 5 .
#> 59: 5 5 5 5
#> 60: 5 . . .
#> 61: 5 5 5 5
#> 62: 5 5 5 5
#> 63: =6 =6 =6 =6
#> 64: 6 6 6 6
#> 65: 6 . . 6
#> 66: 6 6 6 6
#> 67: 6 6 6 6
#> 68: 6 6 6 6
#> 69: =7 =7 =7 =7
#> 70: 7 7 7 7
#> 71: . . 7 .
#> 72: 7 7 7 7
#> 73: 7 7 7 7
#> 74: 7 . . .
#> 75: 7 7 7 7
#> 76: . . 7 7
#> 77: =8 =8 =8 =8
#> 78: 8 8 8 8
#> 79: 8 8 8 8
#> 80: 8 8 8 8
#> 81: 8 8 8 8
#> 82: =9 =9 =9 =9
#> 83: 9 9 9 9
#> 84: 9 9 9 9
#> 85: 9 . . .
#> 86: 9 9 9 9
#> 87: 9 9 9 9
#> 88: . 9 . .
#> 89: =10 =10 =10 =10
#> 90: 10 10 10 10
#> 91: 10 . 10 10
#> 92: 10 10 10 10
#> 93: == == == ==
#> 94: *- *- *- *-
#> 95: !!!hum2abc: -Q ''
#> 96: !!!title: @{PC#}. @{OTL@@DE}
#> 97: !!!YOR1: 371 vierstimmige Choralgesänge von Jo***
#> 98: !!!YOR2: 4th ed. by Alfred Dörffel (Leipzig: B***
#> 99: !!!YOR2: c.1875). 178 pp. Plate "V.A.10". reprint:***
#> 100: !!!YOR4: Chorales (New York: Associated Music Publi***
#> 101: !!!SMS: B&H, 4th ed, Alfred Dörffel, c.1875, p***
#> 102: !!!EED: Craig Stuart Sapp
#> 103: !!!EEV: 2009/05/22
#> ######################## ^^^ chor004.krn ^^^ #########################
#> (***five global comments truncated due to screen size***)
#>
#> humdrumR corpus of four pieces.
#>
#> Data fields:
#> Token :: character
#> *humdrumR:::timecount(...) :: integer
#>
show(within(humData, timecount(Token, unit = tactus(TimeSignature))))
#> ######################## vvv chor001.krn vvv #########################
#> 1: !!!COM: Bach, Johann Sebastian
#> 2: !!!CDT: 1685/02/21/-1750/07/28/
#> 3: !!!OTL@@DE: Aus meines Herzens Grunde
#> 4: !!!OTL@EN: From the Depths of My Heart
#> 5: !!!SCT: BWV 269
#> 6: !!!PC#: 1
#> 7: !!!AGN: chorale
#> 8: **kern **kern **kern **kern
#> 9: *ICvox *ICvox *ICvox *ICvox
#> 10: *Ibass *Itenor *Ialto *Isoprn
#> 11: *I"Bass *I"Tenor *I"Alto *I"Soprano
#> 12: *>[A,A,B] *>[A,A,B] *>[A,A,B] *>[A,A,B]
#> 13: *>norep[A,B] *>norep[A,B] *>norep[A,B] *>norep[A,B]
#> 14: *>A *>A *>A *>A
#> 15: *clefF4 *clefGv2 *clefG2 *clefG2
#> 16: *k[f#] *k[f#] *k[f#] *k[f#]
#> 17: *G: *G: *G: *G:
#> 18: *M3/4 *M3/4 *M3/4 *M3/4
#> 19: *MM100 *MM100 *MM100 *MM100
#> 20: -1 -1 -1 -1
#> 21: =1 =1 =1 =1
#> 22: 1 1 1 1
#> 23: 2 2 2 .
#> 24: . 2 . .
#> 25: 3 3 3 3
#> 26: =2 =2 =2 =2
#> 27: 4 4 4 4
#> 28: 5 5 . .
#> 29: . . . 5
#> 30: 6 6 6 6
#> 31: =3 =3 =3 =3
#> 32: 7 7 7 7
#> 33: . 7 7 .
#> 34: 8 8 8 .
#> 35: 8 . 8 8
#> 36: 9 9 9 9
#> 37: =4 =4 =4 =4
#> 38: 10 10 10 10
#> 39: 12 12 12 12
#> 40: =5 =5 =5 =5
#> 41: 13 13 13 13
#> 42: 14 14 14 .
#> 43: 15 15 15 15
#> 44: =6 =6 =6 =6
#> 45: 16 16 16 16
#> 46: 17 17 . 17
#> 47: 18 18 18 .
#> 48: . 18 . .
#> 49: =7 =7 =7 =7
#> 50: 19 19 19 19
#> 51-133::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
#> ######################## ^^^ chor001.krn ^^^ #########################
#>
#> (two more pieces...)
#>
#> ######################## vvv chor004.krn vvv #########################
#> 1-53::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
#> 54: 16 16 16 16
#> 55: . . 16 .
#> 56: =5 =5 =5 =5
#> 57: 17 17 17 17
#> 58: . . 17 .
#> 59: 18 18 18 18
#> 60: 18 . . .
#> 61: 19 19 19 19
#> 62: 20 20 20 20
#> 63: =6 =6 =6 =6
#> 64: 21 21 21 21
#> 65: 21 . . 21
#> 66: 22 22 22 22
#> 67: 23 23 23 23
#> 68: 24 24 24 24
#> 69: =7 =7 =7 =7
#> 70: 25 25 25 25
#> 71: . . 25 .
#> 72: 26 26 26 26
#> 73: 27 27 27 27
#> 74: 27 . . .
#> 75: 28 28 28 28
#> 76: . . 28 28
#> 77: =8 =8 =8 =8
#> 78: 29 29 29 29
#> 79: 30 30 30 30
#> 80: 31 31 31 31
#> 81: 32 32 32 32
#> 82: =9 =9 =9 =9
#> 83: 33 33 33 33
#> 84: 34 34 34 34
#> 85: 34 . . .
#> 86: 35 35 35 35
#> 87: 36 36 36 36
#> 88: . 36 . .
#> 89: =10 =10 =10 =10
#> 90: 37 37 37 37
#> 91: 38 . 38 38
#> 92: 39 39 39 39
#> 93: == == == ==
#> 94: *- *- *- *-
#> 95: !!!hum2abc: -Q ''
#> 96: !!!title: @{PC#}. @{OTL@@DE}
#> 97: !!!YOR1: 371 vierstimmige Choralgesänge von Jo***
#> 98: !!!YOR2: 4th ed. by Alfred Dörffel (Leipzig: B***
#> 99: !!!YOR2: c.1875). 178 pp. Plate "V.A.10". reprint:***
#> 100: !!!YOR4: Chorales (New York: Associated Music Publi***
#> 101: !!!SMS: B&H, 4th ed, Alfred Dörffel, c.1875, p***
#> 102: !!!EED: Craig Stuart Sapp
#> 103: !!!EEV: 2009/05/22
#> ######################## ^^^ chor004.krn ^^^ #########################
#> (***five global comments truncated due to screen size***)
#>
#> humdrumR corpus of four pieces.
#>
#> Data fields:
#> Token :: character
#> *humdrumR:::timecount(Token, unit = tactus(TimeSignature)) :: integer
#>