minVL - computing minimal voice leadings

This is an R package for computing minimal voice leadings between chords, after Tymcozko (2006). The package is written in C++ for speed.

Installation

if (!require("devtools")) install.packages("devtools")
devtools::install_github("pmcharrison/minVL")

Example usage

min_vl

min_vl computes the minimal voice leading between two sets of pitch classes or pitches.

library(minVL)

# Compute the minimal voice leading between a G7 chord and a C major chord
G7 <- c(2, 5, 7, 11) # these are pitch classes
C <- c(0, 4, 7)
min_vl(G7, C, elt_type = "pc", norm = "euclidean")
min_vl(G7, C, elt_type = "pc", norm = "taxicab")

# E minor is closer to C major than Eb minor
Emin <- c(4, 7, 11)
Ebmin <- c(3, 6, 10)
min_vl(Emin, C)$dist # distance = 1
min_vl(Ebmin, C)$dist # distance = 4

vl_dist

vl_dist computes the voice-leading distance between two sets of pitches or pitch classes s1 and s2, where the ith element of s1 is assumed to move to the ith element of s2.

library(minVL)
Emin <- c(4, 7, 11)
Ebmin <- c(3, 6, 10)
vl_dist(Emin, Ebmin, elt_type = "pc", norm = "euclidean")

Testing

The package includes regression tests that test the minimal voice-leading implementation against that on Dmitri Tymoczko's website (http://dmitri.mycpanel.princeton.edu/software.html).

References

Tymoczko D (2006). “The geometry of musical chords.” Science, 313(5783), 72–74. https://doi.org/10.1126/science.1126287