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Manuscript Title: Isometric representation of two-dimensional matrices.
Authors: A. Choudry
Program title: MATPLT
Catalogue identifier: ACQM_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 1(1970)277
Programming language: Fortran.
Computer: IBM 360/50.
Operating system: RAX.
RAM: 14K words
Word size: 8
Peripherals: graph plotter.
Keywords: General purpose, Isometric, Matrix.
Classification: 4.8.

Nature of problem:
Quite frequently the numerical results of a theoretical calculation, as also the data from an experiment, are obtained in the form of a table or matrix, which describes a two-dimensional distribution of a physical quantity, e.g. charge distribution on a plate, neutron flux on the surface of a large detector, etc. In order to visually survey the entire data at a glance, the ideal presentation would be a three- dimensional model of the distribution in which the height, for example, corresponds to the value of the physical quantity. A similar visual effect can be obtained by a two-dimensional plot having a 45 degree perspective and conforming to the optical constraint that visually hidden parts of the distribution are not drawn.

Solution method:
A main driver program computes or reads in the two-dimensional array to be plotted which is already specified to be in a common block. The main program now calls a FORTRAN subroutine MATPLT which retrieves the array from the common block and generates a deck of punched cards as output. The punched output contains instructions for an off-line plotter to plot the columns of the input matrix as histograms. Each successive column is plotted with 'shifted' origin. Furthermore before plotting a bin a check is made to see if the bin is obscured by the already plotted part of the distribution.

Running time:
To generate plotter input for a typical 50X50 matrix it takes approximately one minute including compilation on an IBM 360/50 computer. The plotter instructions were generated for a Benson-Lehner digital plotter.