# Arbitrary Precision for decimals in C# help?

Here is my current code for computing Pi using the chudnovsky method in c#:

```using System;
using System.Diagnostics;
using System.IO;
using java.math;

namespace pi.chudnovsky
{
public class Program
{
static Double Factorial(Double fact)
{
//begin factorial function
if (fact <= 1)
return 1;
else
return fact * Factorial(fact - 1); //loops multiplication until the factorial is reached
}
static Double doSummation(Double maxPower)
{
//begin chudnovsky summation function
Double sum = 0;
for (int i = 0; i <= maxPower; i++) //starts at i=0
{
sum += ((Math.Pow(-1, i)) * Factorial(6 * i) * (13591409 + 5451401 * i)) / (Factorial(3 * i) * Factorial(i) * Factorial(i) * Factorial(i) * Math.Pow(640320, (3 * i + 1.5))); //chudnovsky algorithm
}
return sum;
}
static void Main(string[] args)
{
int num;
Console.WriteLine("Enter how many terms to compute Chudnovsky summation: ");
//begin stopwatch
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
//parse user input
//perform calculation
Double inv = 1 / (12 * doSummation(num));
//stop stopwatch
stopwatch.Stop();
//display info
Console.WriteLine(inv);
Console.WriteLine("3.14159265358979323846264338327950288419716939937510");
Console.WriteLine("Time elapsed: {0}", stopwatch.Elapsed.TotalMilliseconds);
//write to pi.txt
TextWriter pi = new StreamWriter("pi.txt");
pi.WriteLine(inv);
pi.Close();
//write to stats.txt
TextWriter stats = new StreamWriter("stats.txt");
stats.WriteLine(stopwatch.Elapsed.TotalMilliseconds);
stats.Close();
}
}
}
```

So, I've included the J# library, and included java.math. Now when I replace all the "double"s with "BigDecimal"s, I get these compile errors:

http://f.cl.ly/items/1r2X26470d0d0n260p0p/Image%202011-11-14%20at%206.16.19%20PM.png

I know that this isn't the problem with me using Int for the loops, as it worked perfectly with Doubles. My question is, how do you resolve these errors relating to int and BigDecimal, or can you recommend another arbitrary precision library?

I've tried using XMPIR, have gotten everything to compile, but I get:

http://f.cl.ly/items/1l3C371j2u3z3n2g3a0j/Image%202011-11-14%20at%206.20.24%20PM.png

So I can I use p/invoke to include xmpir so I can use whatever the bigdecimal class is?

Can you not convert your int's to BigDecimal's before comparing them?

I assume you understand the problem here is that there is no operator overload for the greater, less than, etc. signs on the BigDecimal class that accepts an int.