Most efficient way to find smallest of 3 numbers Java?

Chris picture Chris · Mar 6, 2012 · Viewed 144k times · Source

I have an algorithm written in Java that I would like to make more efficient. A part that I think could be made more efficient is finding the smallest of 3 numbers. Currently I'm using the Math.min method as below:

double smallest = Math.min(a, Math.min(b, c));

How efficient is this? Would it be more efficient to replace with if statements like below:

double smallest;
if (a <= b && a <= c) {
    smallest = a;
} else if (b <= c && b <= a) {
    smallest = b;
} else {
    smallest = c;
}

Or if any other way is more efficient

I'm wondering if it is worth changing what I'm currently using?

Any speed increase would be greatly helpful

Answer

wpgreenway picture wpgreenway · Mar 6, 2012

For a lot of utility-type methods, the apache commons libraries have solid implementations that you can either leverage or get additional insight from. In this case, there is a method for finding the smallest of three doubles available in org.apache.commons.lang.math.NumberUtils. Their implementation is actually nearly identical to your initial thought:

public static double min(double a, double b, double c) {
    return Math.min(Math.min(a, b), c);
}