/* graph.mod - graph visualization */

/* Written in GNU MathProg by Andrew Makhorin <mao@gnu.org> */

/* This model creates a picture in EPS format to visualize a graph. */

param file, symbolic, default "graph.eps";

/* output file to write the picture */

param R, default 2;

/* radius to draw vertices, in mm */

param n, integer, > 0;

/* number of vertices */

set V, default 1..n;

/* set of vertices */

set E, within V cross V;

/* set of edges */

param x{i in V}, default 50 * cos((i - 1) / card(V) * 8 * atan(1));

param y{i in V}, default 50 * sin((i - 1) / card(V) * 8 * atan(1));

/* x[i] and y[i] are coordinates of node i, in mm */

param x0 := (min{i in V} x[i]) - R - 3.0;

param y0 := (min{i in V} y[i]) - R - 3.0;

param x1 := (max{i in V} x[i]) + R + 3.0;

param y1 := (max{i in V} y[i]) + R + 3.0;

printf "%%!PS-Adobe-3.0 EPSF-3.0\n" > file;

printf "%%%%BoundingBox: 0 0 %d %d\n",

      (72 / 25.4) * (x1 - x0), (72 / 25.4) * (y1 - y0) >> file;

printf "/Helvetica findfont 6 scalefont setfont\n" >> file;

printf "/mm { 72 mul 25.4 div } def\n" >> file;

for {(i,j) in E}

{     printf "newpath\n" >> file;

      printf "%g mm %g mm moveto\n", x[i] - x0, y[i] - y0 >> file;

      printf "%g mm %g mm lineto\n", x[j] - x0, y[j] - y0 >> file;

      printf "closepath\n" >> file;

      printf "stroke\n" >> file;

}

for {i in V}

{     printf "newpath\n" >> file;

      printf "%g mm %g mm %g mm 0 360 arc\n",

         x[i] - x0, y[i] - y0, R >> file;

      printf "closepath\n" >> file;

      printf "gsave 1 1 1 setrgbcolor fill grestore\n" >> file;

      printf "stroke\n" >> file;

      printf "%g mm %g mm moveto\n",

         x[i] - (if i <= 9 then 1.2 else 1.8) - x0,

         y[i] - 0.8 - y0 >> file;

      printf "( %d ) show\n", i >> file;

}

printf "showpage\n" >> file;

printf "%%%%EOF\n" >> file;

data;

param

:  V  :  x     y :=

   1     0    40

   2    38    12

   3    24   -32

   4   -24   -32

   5   -38    12

   6   -19    26

   7    19    26

   8    31   -10

   9     0   -32

  10   -31   -10

  11    -9    12

  12     9    12

  13    14    -5

  14     0   -15

  15   -14    -5

  16     0     0 ;

set E :=

   (1,*)  6 10 16 12  7

   (2,*)  7  6 16 13  8

   (3,*)  8  7 16 14  9

   (4,*)  9  8 16 15 10

   (5,*) 10  9 16 11  6

   (6,*) 14

   (7,*) 15

   (8,*) 11

   (9,*) 12

  (10,*) 13

  (11,*) 12 15

  (12,*) 13

  (13,*) 14

  (14,*) 15 ;

end;