This program ws written by Jacqueline Meulman while at Bell Laboratories in
the 1970's.  This version was put together by Patrick Groenen.  Both are at
Leiden University in The Netherlands.

Prefmap3 is a program for fitting additional points or vectors into an
existing configuration. For more details see the Prefmap-3 User's Guide.

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prefmap3.f
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This file contains the Fortran code of the Prefmap-3 program. The memory 
allocation is controlled by the subroutine DECLAR. If you need more 
memory, then the size of array A in DECLAR should be increased.

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MacOS version
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The MacOS version is fat-binary, which implies that it contains an 68K 
version for older Macintosh models and PowerPC native code for models 
running MacOS on a PowerPC CPU.  The file prefmap3.hqx can be decoded by 
Stuffit Expander or equivalent programs.  The memory allocation is 
dynamic so that the memory can be increased by enlarging the preferred 
memory size in the Get Info box of Prefmap3.  Prefmap3 is started by 
double clicking the Prefmap3 application. This invokes a file dialog 
box in which the input file has to be specified. If the amount of output 
is too large then the output is saved in the file 'Prefmap3 output'.

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DOS version
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This consists of two files: prefmap3.exe and dosxmsf.exe. The first file is
the program, the second file is needed for dynamic memory allocation. The
program is started by executing the command

	prefmap3<input.fil

to obtain the output on screen (where input.fil is the input file), or

	prefmap3<input.fil>output.fil

to direct the output to the file output.fil.

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Here are some important references to PREFMAP, copied by Kruskal from
prefmap3b/readme:

Meulman,J., Heiser,W., & Carroll,J.D. (1986). How to use PREFMAP3.
Unpublished manuscript, AT&T Bell Laboratories, Murray Hill, NJ.

Carroll,J.D. (1972). "Individual differences and multidimensional scaling".
In R.N.Shepard, A.K.Romney & S.B.Nerlove (Eds.),
"Multidimensional Scaling: Theory and Applications in the Behavioral
Sciences" (Vol.1, pp.105-155). New York and London: Seminar Press.
[Reprinted in P.Davies & A.P.M.Coxon (Eds.) (1984), "Key Texts in
Multidimensional Scaling", pp. 267-301, Exeter, NH: Heinemann.]

Carroll,J.D. (1980). "Models and methods for multidimensional
analysis of preferential choice (or other dominance) data".
In E.D.Lantermann & H.Feger (Eds.), "Similarity and Choice", pp. 234-289.
Bern: Hans Huber.