iv – determine interval-class vectors for successive vertical sonorities for Humdrum inputs
`` iv [inputfile ...] [> outputfile.iv]``
The iv command is used to determine the interval-class vector for any of five set-theory related inputs: pitch (**semits), pitch-class (**pc), normal form (**nf), prime form (**pf), or Fortean set name (**pcset). An interval-class vector is a six-element numerical list that indicates the abundance of various interval-classes (from 1 semitone to 6 semitones) for some pitch-class set. See REFERENCES below.
When provided with **semits or **pc inputs, iv treats each input record as a set of pitches. Unisons and other pitch-class duplications have no effect on the output. Rests within a set of pitches are ignored; where an input record consists solely of one or more rests, a null-token is output.
The iv command is able to translate any of the representations listed below. For descriptions of the various input representations (including **iv) refer to Section 2 (Representation Reference) of this reference manual.
It is recommended that output files produced using the iv command should be given names with the distinguishing `.iv’ extension.
**iv interval-class vector representation **nf normal form representation **pc pitch-class representation **pcset Fortean pitch-class set name **pf prime form representation **semits equal-tempered semitones with respect to middle C=0 (e.g. 12 = C5)
Input representations processed by **iv*.*
The iv command provides only a help option:
-h displays a help screen summarizing the command syntax
Options are specified in the command line.
The following command outputs the interval-class vectors for successive sonorities in the input file opus24. The input may be pitches, pitch-classes, normal forms, Fortean set names, etc.
`` iv opus24 > opus24.iv``
DOS 2.0 and up, with the MKS Toolkit. OS/2 with the MKS Toolkit. UNIX systems supporting the Korn shell or Bourne shell command interpreters, and revised awk (1985).
The iv command is a shell script that invokes pcset -v.
Allen Forte, The Structure of Atonal Music. New Haven: Yale University Press, 1973.
John Rahn, Basic Atonal Theory. New York: Longman Inc., 1980.
Straus, J. Introduction to Post-Tonal Theory. Englewood Cliffs, N.J.: Prentice Hall, 1990.
- **Pertinent description in the Humdrum User Guide**
- **Index to Humdrum Commands**
- **Table for Contents for Humdrum User Guide**