Added "night" option to SOCgraphviz, fixed typos

README.md

@@ -32,7 +32,7 @@ To display help and exit, run the respective program without command-line argume
 ### SOCgen
 ```
 $ ./SOCgen 
-Usage: ./SOCgen -n <order> [-r <num>] [--grpahviz] [FILTER ...]
+Usage: ./SOCgen -n <order> [-r <num>] [--graphviz] [FILTER ...]
        -n <order>     Generate SOCs with `order' connected nodes
        -r <num>       Pick directed graphs at random, and exit after having found `num' SOCs
        --graphviz     Output SOCs in Graphviz format, arcs of common parents are highlighted
@@ -42,7 +42,7 @@ Usage: ./SOCgen -n <order> [-r <num>] [--grpahviz] [FILTER ...]
        --no-sink      ... without sink nodes (this logically implies -c)
        --no-source    ... without source nodes (also this logically implies -c)
 
-This program prints the found SOCs as adjacency matrices to stdout, unless --grpahviz has been specified.
+This program prints the found SOCs as adjacency matrices to stdout, unless --graphviz has been specified.
 To exclude (some) of the isomorphic SOCs, it uses a degree-order filter.
 ```
 
@@ -66,7 +66,7 @@ This program verifies the admissibility of simple directed graphs.
 ### SOCgraphviz
 ```
 $ ./SOCgraphviz
-Usage: ./SOCgraphviz <filename>
+Usage: ./SOCgraphviz <filename> [night]
        <filename>     File name with adjacency matrices of simple directed graphs
 
 [FILE FORMAT]
@@ -75,6 +75,7 @@ Usage: ./SOCgraphviz <filename>
        The file `filename' may contain graphs with different order (number of vertices)
 
 This program translates to adjacency matrices into the Graphviz format, and prints them to stdout.
+Try the optional argument ``night'' for star-constallation-like output.
 ```
 
 ### removeiso.py

src/SOCgen.c

@@ -482,7 +482,7 @@ int main(int argc, char *argv[]) {
     }
   }
   if (UNKOPTION || n <= 1) {
-    fprintf(stderr, "Usage: %s -n <order> [-r <num>] [--grpahviz] [FILTER ...]\n", argv[0]);
+    fprintf(stderr, "Usage: %s -n <order> [-r <num>] [--graphviz] [FILTER ...]\n", argv[0]);
     fprintf(stderr, "       -n <order>     Generate SOCs with `order' connected nodes\n");
     fprintf(stderr, "       -r <num>       Pick directed graphs at random, and exit after having found `num' SOCs\n");
     fprintf(stderr, "       --graphviz     Output SOCs in Graphviz format, arcs of common parents are highlighted\n");
@@ -492,7 +492,7 @@ int main(int argc, char *argv[]) {
     fprintf(stderr, "       --no-sink      ... without sink nodes (this logically implies -c)\n");
     fprintf(stderr, "       --no-source    ... without source nodes (also this logically implies -c)\n");
     fprintf(stderr, "\n");
-    fprintf(stderr, "This program prints the found SOCs as adjacency matrices to stdout, unless --grpahviz has been specified.\n");
+    fprintf(stderr, "This program prints the found SOCs as adjacency matrices to stdout, unless --graphviz has been specified.\n");
     fprintf(stderr, "To exclude (some) of the isomorphic SOCs, it uses a degree-order filter.\n");
     return -1;
   }
@@ -556,7 +556,7 @@ int main(int argc, char *argv[]) {
           padlen+3, SOCrate, padlen, ETC);
       fflush(stderr);
     }
-    // Convert graph index `grpahnumber' to the lists parents, children,
+    // Convert graph index `graphnumber' to the lists parents, children,
     // parentslen, childrenlen
     graphnrtolists(n, graphnumber, parents, parentslen, children, childrenlen);
     // Increase checked counter and prepare for next iteration

src/SOCgraphviz.c

@@ -4,11 +4,52 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
 #include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <time.h>
 
+// Global configuration for the "night" mode
+const float maxSize = 0.1;
+const float minSize = 0.001;
+const char *starColors[] = {
+  "white",
+  "lightgray",
+  "darkslategray",
+  "lightyellow",
+  "purple",
+  "cyan",
+  "silver",
+  "khaki", "khaki1", "khaki2", "khaki3", "khaki4",
+  "gold", "gold1", "gold2", "gold3", "gold4",
+  "darkgoldenrod", "darkgoldenrod1", "darkgoldenrod2", "darkgoldenrod3", "darkgoldenrod4",
+  "darkorange", "darkorange1", "darkorange2", "darkorange3", "darkorange4",
+  "coral", "coral1", "coral2", "coral3", "coral4",
+  "chocolate", "chocolate1", "chocolate2", "chocolate3", "chocolate4",
+  "antiquewhite", "antiquewhite1", "antiquewhite2", "antiquewhite3", "antiquewhite4",
+  "azure", "azure1", "azure2", "azure3", "azure4",
+  "bisque", "bisque1", "bisque2", "bisque3", "bisque4",
+  "seashell", "seashell1", "seashell2", "seashell3", "seashell4",
+  "lightyellow", "lightyellow1", "lightyellow2", "lightyellow3", "lightyellow4",
+  "lightpink", "lightpink1", "lightpink2", "lightpink3", "lightpink4",
+  "burlywood", "burlywood1", "burlywood2", "burlywood3", "burlywood4",
+  "lavenderblush", "lavenderblush1", "lavenderblush2", "lavenderblush3", "lavenderblush4",
+};
+const size_t numColors = sizeof(starColors) / sizeof(starColors[0]);
+
+void printgraphhead(char *filename, const int line, const int NIGHT) {
+  printf("strict digraph \"File_%s_line_%d\" {", filename, line);
+  if (NIGHT) {
+    double rsize = minSize + (((double)rand() / RAND_MAX) * (maxSize - minSize));
+    int rcolor = rand() % numColors;
+    printf("  bgcolor=\"black\";");
+    printf("  node [shape=point, color=%s, style=filled, width=%lf, height=%lf];", starColors[rcolor], rsize, rsize);
+    printf("  edge [color=lightgray, penwidth=0.5];");
+  }
+}
 int main(int argc, char *argv[]) {
   // Parse command-line arguments
-  if (argc != 2) {
+  if (argc != 2 && (argc != 3 || strcmp(argv[2], "night") != 0)) {
-    fprintf(stderr, "Usage: %s <filename>\n", argv[0]);
+    fprintf(stderr, "Usage: %s <filename> [night]\n", argv[0]);
     fprintf(stderr, "       <filename>     File name with adjacency matrices of simple directed graphs\n");
     fprintf(stderr, "\n");
     fprintf(stderr, "[FILE FORMAT]\n");
@@ -17,8 +58,11 @@ int main(int argc, char *argv[]) {
     fprintf(stderr, "       The file `filename' may contain graphs with different order (number of vertices)\n");
     fprintf(stderr, "\n");
     fprintf(stderr, "This program translates to adjacency matrices into the Graphviz format, and prints them to stdout.\n");
+    fprintf(stderr, "Try the optional argument ``night'' for star-constallation-like output.\n");
     return -1;
   }
+  const int NIGHT = argc - 2;
+  srand(time(NULL));
 
   // Open file
   FILE *fp;
@@ -33,14 +77,14 @@ int main(int argc, char *argv[]) {
   int n = -1;
   int row = 0;
   int col = 0;
-  printf("strict digraph \"File_%s_line_%d\" {", argv[1], line);
+  printgraphhead(argv[1], line, NIGHT);
   while (!feof(fp)) {
     char ch = fgetc(fp);
     switch (ch) {
       case '{':
         if (row == 0 && col == 0 && headprinted == 0) {
           headprinted = 1;
-          printf("strict digraph \"File_%s_line_%d\" {", argv[1], line);
+          printgraphhead(argv[1], line, NIGHT);
         }
         break;
       case '0':