Performing Math operations on decimal datatype in C#?

Question

I was wondering if the above was at all possible. For example:

Math.Sqrt(myVariableHere); 

When looking at the overload, it requires a double parameter, so I'm not sure if there is another way to replicate this with decimal datatypes.

Answer 1

I don't understand why all the answers to that question are the same.

There are several ways to calculate the square root from a number. One of them was proposed by Isaac Newton. I'll only write one of the simplest implementations of this method. I use it to improve the accuracy of double's square root.

// x - a number, from which we need to calculate the square root // epsilon - an accuracy of calculation of the root from our number. // The result of the calculations will differ from an actual value // of the root on less than epslion. public static decimal Sqrt(decimal x, decimal epsilon = 0.0M) {     if (x < 0) throw new OverflowException("Cannot calculate square root from a negative number");      decimal current = (decimal)Math.Sqrt((double)x), previous;     do     {         previous = current;         if (previous == 0.0M) return 0;         current = (previous + x / previous) / 2;     }     while (Math.Abs(previous - current) > epsilon);     return current; } 

About speed: in the worst case (epsilon = 0 and number is decimal.MaxValue) the loop repeats less than a three times.

If you want to know more, read this (Hacker's Delight by Henry S. Warren, Jr.)

Answer 2

In most cases involving a decimal (currency etc), it isn't useful to take a root; and the root won't have anything like the expected precision that you might expect a decimal to have. You can of course force it by casting (assuming we aren't dealing with extreme ends of the decimal range):

decimal root = (decimal)Math.Sqrt((double)myVariableHere); 

which forces you to at least acknowledge the inherent rounding issues.