C# ModInverse Function

by

Since .Net 4.0+ implements BigInteger with a special modular arithmetics function ModPow (which produces “X power Y modulo Z”), you don’t need a third-party library to emulate ModInverse. If n is a prime, all you need to do is to compute:

a_inverse = BigInteger.ModPow(a, n - 2, n)

For more details, look in Wikipedia: Modular multiplicative inverse, section Using Euler’s theorem, the special case “when m is a prime”. By the way, there is a more recent SO topic on this: 1/BigInteger in c#, with the same approach suggested by CodesInChaos.

More Related Contents:

  1. C# Find Duplicate Values in a Datatable
  2. Why covariance and contravariance do not support value type
  3. Difference between Covariance & Contra-variance
  4. Why doesn’t C# infer my generic types?
  5. Why isn’t there generic variance for classes in C# 4.0?
  6. How does the C# compiler detect COM types?
  7. How do I get the current line number?
  8. How to call a C# library from Native C++ (using C++\CLI and IJW)
  9. Better naming in Tuple classes than “Item1”, “Item2”
  10. Will the dynamic keyword in C#4 support extension methods?
  11. creating WCF ChannelFactory
  12. How to detect a process start & end using c# in windows?
  13. method overloading vs optional parameter in C# 4.0 [duplicate]
  14. C# object initialization of read only collection properties
  15. Reading From a Text File in C#
  16. Start may not be called on a promise-style task. exception is coming
  17. Impersonate user in Windows Service
  18. Datetime in C# add days
  19. Is Graphics.DrawImage too slow for bigger images?
  20. Does the System.Windows.Forms.Timer run on a different thread than the UI?
  21. How to get first record in each group using Linq
  22. Better way to query a page of data and get total count in entity framework 4.1?
  23. Connecting to Oracle Database through C#?
  24. DataGridView column footer c#.net winforms
  25. How to add and get Header values in WebApi
  26. Using DataContractSerializer to serialize, but can’t deserialize back
  27. How to get current working directory path c#?
  28. IsAssignableFrom, IsInstanceOfType and the is keyword, what is the difference?
  29. How to get content type of a web address?
  30. Adding different type of generic objects into generic list

Leave a Comment