Javascript's MATH object has a random method that returns from the set [0,1) 0 inclusive, 1 exclusive. Is there a way to return a truly random method that includes 1.
e.g.
var rand = MATH.random()*2;
if(rand > 1)
{
rand = MATH.floor(rand);
}
return rand;
While this always returns a number from the set [0,1] it is not truly random.
Whether it's inclusive of the boundaries shouldn't matter; indeed, strictly speaking what you're trying to do doesn't really make sense. Remember that under a continuous probability distribution, the probability of getting a specific value is infinitesimal anyway, so mathematically speaking, you'll never see the exact value of 1.
Of course, in the world of computers, the distribution of an RNG isn't truly continuous, so it's "possible" that you'll encounter a specific value (whatever that means), but the fact that you're relying on an a limitation of how real numbers are stored hints at problems with your approach to the problem you're trying to solve.
You want it to include 1?
return 1 - Math.random();
However, I think this is one of those questions which hints at other problems. Why do you need to include 1? There's probably a better way to do it.
This will return [0,1] inclusive:
if(MATH.random() == 0)
return 1;
else
return MATH.random();
Explanation: If the first call to random() returns 0, return 1. Otherwise, call random again, which will be [0,1). Therefore, it will return [0,1] all inclusive.
The Math.random function returns a random number between 0 and 1, where 0 is inclusive and 1 is exclusive. This means that the only way to properly distribute the random numbers as integers in an interval is to use an exclusive upper limit.
To specify an inclusive upper limit, you just add one to it to make it exclusive in the calculation. This will distribute the random numbers correctly between 7 and 12, inclusive:
var min = 7;
var max = 12;
var rnd = min + Math.floor(Math.random() * (max - min + 1));