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c#performancealgorithmexponentiation

Fast exponentiation implementation

Could someone please point out a site where I can find an algorithm to efficiently calculate integer exponentiation to large powers using C#?

eg. I want to calculate 2^60000 or 3^12345

Solution

  • Unless this is homework, you probably don't want to roll your own implementation of arbitrary precision exponentiation. Calculating large exponents of the type you describe is complicated - performance aside.

    I would recommend using one of the existing arbitrary precision arithmetic libraries, like GMP - most of which have libraries to access them from C#.

    F# has support for arbitrary precision arithmetic using the BigInt class (which you can also access from C# if you import the assembly it's in). However, I don't know how optimized BigInt exponentiation is.

    If you're simply trying to learn about efficient algorithms for exponentiation, you may want to look into the Square-And-Multiply algorithm for exponentiation.