Generating random numbers within a range determined by elements in another array

Hello,

I was wondering if there is an efficient way to generate a random integer within a range depending on an element in another array. Perhaps a small example will explain better:

1 must generate a random number in [3 7];
2 must generate a random number in [1 3];
3 must generate a random number in [44 66]

So for the vector [3 1 2] I would want to get another vector [59 4 2], for example.

I was thinking of using arrayfun to do this but I don't know if there is a more efficient way?

Any help/advice would be greatly appreciated.

Thanks

Answer 1

[Iain]

Array = [3 7; 1 3; 44 66];

Choose your row, "i"

NewRandom = roundingfunctionofchoice(rand(size(i)).*(Array(i,2)-Array(i,1)) + Array(i,1));

If you set i = [3 1 2], you'll get what you want.

[Ray]

Thanks! I tested this on a huge example and it was very efficient, better than my use of for-loops/while-loops.

Answer 2

[Image Analyst]

Did you look at the help for rand() and notice the first example? Here it is:

Example 1
Generate values from the uniform distribution on the interval [a, b]:
r = a + (b-a).*rand(100,1);

Basically it all comes down to that. Do that 3 times with different a and b depending on what the 3 numbers are. Is this homework?

[Ray]

I am familiar with the rand function. I was looking more for a compact/efficient approach to achieving the random number generation based on differing ranges, unique to each element in the first array (see accepted answer above).