HODGE
An implementation of the Hodgepodge Machine

HODGE is a C program which implements the "hodgepodge" machine.

HODGE is a two dimensional cellular automaton which is inspired by the behavior of various catalytic chemical reactions. The program includes a few variables which control the behavior. As these variables are set, the computed states may settle down, become cyclic or chaotic, or sustain the movement of strange coherent patterns.

Languages:

HODGE is available in a C version.

Author:

Martin Gerhardt, Heike Schuster, of the University of Bielefeld.

Related Data and Programs:

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MANDELBROT, a FORTRAN90 program which generates an ASCII PPM image of the Mandelbrot set;

SIR_SIMULATION is a MATLAB program which simulates the spread of a disease through a hospital room of M by N beds, using the SIR (Susceptible/Infected/Recovered) model.

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Reference:

1. Alexander Dewdney,
   Computer Recreations: The Hodgepodge Machine Makes Waves,
   Scientific American,
   Volume 259, Number 8, August 1988, pages 104-107.

Source Code:

• hodge.c, the source code;
• hodge.csh, commands to compile and load the source code;

Examples and Tests

• hodge.map, a color map needed by the program;
• hodge_output.txt, output from a run of the program;
• hodge_000.ppm, PPM file 0;
• hodge_000.png, a PNG version of the file.
• hodge_001.ppm, PPM file 1;
• hodge_001.png, a PNG version of the file.
• hodge_002.ppm, PPM file 2;
• hodge_002.png, a PNG version of the file.
• hodge_003.ppm, PPM file 3;
• hodge_003.png, a PNG version of the file.
• hodge_004.ppm, PPM file 4;
• hodge_004.png, a PNG version of the file.
• hodge_005.ppm, PPM file 5;
• hodge_005.png, a PNG version of the file.
• hodge_006.ppm, PPM file 6;
• hodge_006.png, a PNG version of the file.
• hodge_007.ppm, PPM file 7;
• hodge_007.png, a PNG version of the file.
• hodge_008.ppm, PPM file 8;
• hodge_008.png, a PNG version of the file.
• hodge_009.ppm, PPM file 9;
• hodge_009.png, a PNG version of the file.

List of Routines:

• MAIN is the main program for the Hodge-Podge program.
• GET_STATE computes the state from a cell's value.
• GRID2PPM writes out the grid converted to a binary color portable pixmap.
• HODGE carries out the main loop.
• INITIALIZE initializes the cells.
• LOAD_COLOR_MAP loads a color map.
• MAP maps an index to the grid structure.
• RGB_COLOR turns a value into an RGB string.
• SCOUNT counts the number of cells in a specified state.
• VSUM sums the neighbor cell values.

You can go up one level to the C source codes.