pf – determine prime form for successive Humdrum vertical sonorities
`` pf [inputfile ...] [> outputfile.pf]``
The pf command is used to determine the prime form for any of five set-theory related inputs: pitch (**semits), pitch-class (**pc), normal form (**nf), interval-vector (**iv), or Fortean set name (**pcset).
“Prime form” is a standardized way of representing the symmetrical interval structure for any arbitrary set of pitch-classes. Prime form is the most intervalically compact representation of a pitch-class set, transposed to begin on pitch-class 0 – where inversions are deemed equivalent. By way of example, any major or minor chord, having any root, in any inversion, consisting of any number of notes, with any spelling, will have the prime form: 0,3,7. See REFERENCES below.
When provided with **semits or **pc inputs, pf 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 pf command can also accept other set theoretic inputs, such as **nf, **iv, **pcset, as well as **pf itself.
The following table identifies the input representations accepted by pf. For descriptions of the various input representations (including **pf) refer to Section 2 (Representation Reference) of this reference manual.
It is recommended that output files produced using the pf command should be given names with the distinguishing `.pf’ 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 **pf*.*
The pf 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 prime form for the sets formed by successive sonorities in the input file opus24. The input may be pitches, pitch-classes, Fortean set names, etc.
`` pf opus24 > opus24.pf``
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 pf command is a shell script that invokes pcset -p.
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**