blob: 9773e370e6bc7abf0fbe0472717fa2bc12e1a15c [file] [log] [blame]
 /* * Paretoormal distribution table generator * * This distribution is simply .25*normal + .75*pareto; a combination * which seems to match experimentally observed distributions reasonably * well, but is computationally easy to handle. * The entries represent a scaled inverse of the cumulative distribution * function. * * Taken from the uncopyrighted NISTnet code. */ #include #include #include #include #include #include #include #include #define TABLESIZE 16384 #define TABLEFACTOR NETEM_DIST_SCALE static double normal(double x, double mu, double sigma) { return .5 + .5*erf((x-mu)/(sqrt(2.0)*sigma)); } static const double a=3.0; static int paretovalue(int i) { double dvalue; i = 65536-4*i; dvalue = (double)i/(double)65536; dvalue = 1.0/pow(dvalue, 1.0/a); dvalue -= 1.5; dvalue *= (4.0/3.0)*(double)TABLEFACTOR; if (dvalue > 32767) dvalue = 32767; return (int)rint(dvalue); } int main(int argc, char **argv) { int i,n; double x; double table[TABLESIZE+1]; for (x = -10.0; x < 10.05; x += .00005) { i = rint(TABLESIZE*normal(x, 0.0, 1.0)); table[i] = x; } printf( "# This is the distribution table for the paretonormal distribution.\n" ); for (i = n = 0; i < TABLESIZE; i += 4) { int normvalue, parvalue, value; normvalue = (int) rint(table[i]*TABLEFACTOR); parvalue = paretovalue(i); value = (normvalue+3*parvalue)/4; if (value < SHRT_MIN) value = SHRT_MIN; if (value > SHRT_MAX) value = SHRT_MAX; printf(" %d", value); if (++n == 8) { putchar('\n'); n = 0; } } return 0; }