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Abstract
The program is written in ASA FORTRAN IV and consists of the main program (MAIN) with 14 subroutines. Subroutines SETUP, PLOT, GRID, SCALE, and 01s are microfilm-dependent and therefore must be replaced with the equivalent routines written for the high resolution plotting device available at the user's installation. The calls to these subroutines are flagged by comment cards in the program listings to aid in this conversion. Users may implement the program with page plotting capability only (though this is not recommended) by simply deleting the microfilm dependent subroutines and the calls to the same. Subroutine CALC is available in two versions. The first version, listed on page 7, directly calculates the elements of the projection vector, at, for each observation vector x
i--hence the projection vector is calculated anew for each observation vector. The second version, listed on page 6, uses the pre-calculated values of at, stored in the matrix Fstar (listed on pages 18-26). Either version of the subroutine may be used: the first version having the advantage of smaller core requirements, and the second version having the advantage of much faster execution times but larger core requirements (about 5000 36-bit words). The present version of the program allows up to 250 observation vectors, 50 variables, and computes 99 plotting points per observation vector. This version requires approximately 58K words using the second version of CALC. By reducing the number of observations allowed from 250 to 100, the core requirements are reduced to about 42K words. Note that these core requirements include the microfilm dependent coding, which is about 5K. Reduction of the program to a core requirement of 32K (ideal for many installations) could easily be achieved by reducing the number of observation vectors. to 100, using the first version of CALC, and eliminating the microfilm dependent coding.
Citation
Nance, W.L.; Polmer, B.H.; Keith, G.C. 1975. Programming Details for MDPLOT: A Program for Plotting Multi-Dimensional Data. Gen. Tech. Rep. SO-7. New Orleans, LA: U.S. Dept of Agriculture, Forest Service, Southern Forest Experiment Station. 26 p.
