Initial revision
diff --git a/isisd/topology/random.c b/isisd/topology/random.c
new file mode 100644
index 0000000..d4ef995
--- /dev/null
+++ b/isisd/topology/random.c
@@ -0,0 +1,154 @@
+/*********************************************************************/
+/* */
+/* current processor time in seconds */
+/* difference between two calls is processor time spent by your code */
+/* needs: <sys/types.h>, <sys/times.h> */
+/* depends on compiler and OS */
+/* */
+/*********************************************************************/
+
+#include <sys/types.h>
+#include <sys/times.h>
+
+float timer()
+ { struct tms hold;
+
+ times(&hold);
+ return (float)(hold.tms_utime) / 60.0;
+ }
+
+
+/*********************************************************************/
+/* */
+/* Family of random number generators */
+/* */
+/* Initialisation: */
+/* void init_rand ( seed ); */
+/* long seed - any positive number */
+/* if seed<=0 init_rand takes time */
+/* from timer instead of seed */
+/* */
+/* Whole number uniformly distributed on [0,n): */
+/* long nrand (n); */
+/* long n */
+/* */
+/* Real number uniformly distributed on [0,1] */
+/* double rand01(); */
+/* */
+/* Real number with Gauss(0,1) disitribution: */
+/* double randg01(); */
+/* */
+/* Algorithm: */
+/* x(n+1) = (x(n) * 5^13) mod 2^31 */
+/* */
+/*********************************************************************/
+
+unsigned long internal_seed;
+
+void init_rand ( init_seed )
+
+long init_seed;
+
+{ internal_seed = ( init_seed > 0 )
+ ? (unsigned long) init_seed
+ : (unsigned long) timer();
+
+
+ /* only odd numbers are acceptable */
+ if ( internal_seed % 2 == 0 ) internal_seed --;
+}
+
+/*********************************************************************/
+/* */
+/* Internal function irand may depend on OS and compiler */
+/* */
+/* irand assumption: */
+/* unsigned long i,j; */
+/* if i*j > max(unsigned long) */
+/* 1. No overflow interruption */
+/* 2. i*j = i*j mod max(unsigned long) */
+/* */
+/* This assumption is true for a lot of computers. */
+/* If your computer fails: */
+/* rename: irand <---> xrand */
+/* */
+/*********************************************************************/
+
+#define A 1220703125
+#define B 2147483647
+#define BF 2147483647.
+
+static long irand ()
+
+{ internal_seed = ( internal_seed * A ) & B;
+ return (long) internal_seed ;
+}
+
+/*********************************************************************/
+/* */
+/* computer independent variant of irand */
+/* */
+/*********************************************************************/
+
+
+#define T15 32768
+#define T16 65536
+#define A1 37252
+#define A2 29589
+
+static long xrand()
+
+{ unsigned long is1, is2;
+
+ is1 = internal_seed / T15;
+ is2 = internal_seed % T15;
+
+ internal_seed = ( (((is2 * A1) + (is1 * A2))% T16 )* T15 + (is2 * A2) ) & B;
+ return (long) ( internal_seed ) ;
+}
+
+
+/*********************************************************************/
+
+
+double rand01()
+
+{ return (double) irand() / BF ;
+}
+
+/*********************************************************************/
+
+#define NK 12
+
+double randg01()
+
+{ int i;
+ double sum = 0;
+
+ for ( i = 0; i < NK; i++ ) sum += rand01();
+ return sum - 6.;
+
+ /* if NK != 12 then you must return (12/NK)*sum - (NK/2) */
+}
+
+#undef NK
+
+
+/*********************************************************************/
+
+long nrand ( n )
+
+long n;
+
+{ return (long) ( rand01() * (double) n );
+}
+
+/*********************************************************************/
+
+#undef A
+#undef A1
+#undef A2
+#undef B
+#undef BF
+#undef T15
+#undef T16