int MVTRand::getRange(int pMin, int pMax)
{
if (pMin == pMax)
return pMin;
if (pMax >= RAND_MAX)
{
// Note (maxw):
// On some platforms RAND_MAX is MAX_INT, but on other platforms
// it's much smaller. The code below is just a quick patch for the latter case.
// We could attempt something better (e.g. some computation based on
// multiple evaluations of rand()), or we could use a different random
// generator. I preferred a simple patch at this point, for historical/continuity
// reasons (and because this issue/usage is very infrequent).
return (int)getDoubleRange((double)pMin, (double)pMax);
}
// Tests widely use random numbers
// This makes it easy for picking number randomly in a range
// pMin and pMax values are included.
//For example: randInRange( 1, 100 ) -> random number from 1 to 100
// randInRange( 0, 1 ) -> random true or false
int normalized = 1 + pMax - pMin;
assert(normalized > 0 || normalized < RAND_MAX);
int randval; // Will get a well distributed value from 0 to normalized -1
const int bucket_size = RAND_MAX / normalized;
do
{
randval = rand() / bucket_size;
}
while (randval >= normalized);
return pMin + randval;
}
double CRandomGenerator::nextDouble(double lower, double upper)
{
return getDoubleRange(lower, upper)();
}
