We don't have any idea what you are trying to do! One way to "select the number of points" would be to use the random number generator, multiply by 1000, to get a number from 0 to 999, but this almost certainly isn't what you mean! Do you have existing code that you are trying to fix up? Can you state the problem better (for example, "I'm trying to generate a 10 Hz sine wave with a new point every millisecond and want to know how many data points to use in order to generate 10 cycles").
Show code if you have it!
BS
