private static BigInteger Fibonacci_MatrixExponentiation(int n)
{
//-------------------------------
Stopwatch t = new Stopwatch();
t.Start();
//---------------------------------
if (n < 0)
{
return(BigInteger.MinusOne);
}
else if (n == 1)
{
return(n);
}
matrix2x2 res = new matrix2x2 {
a = 1, b = 0, c = 0, d = 1
};
matrix2x2 fib = new matrix2x2 {
a = 1, b = 1, c = 1, d = 0
};
do
{
if (n % 2 == 1)
{
res *= fib;
}
fib *= fib;
} while ((n /= 2) > 0);
/*do
* {
* if (n % 2 == 1) Mult2x2Matrix(ref result, F);
* Mult2x2Matrix(ref F, F);
*
* } while ((n/=2) > 0);*/
//---------------------------------
t.Stop();
TimeSpan ts = t.Elapsed;
Console.WriteLine("{0:00}:{1:00}:{2:00}.{3:00}",
ts.Hours, ts.Minutes, ts.Seconds,
ts.Milliseconds / 10);
//---------------------------------
File.WriteAllText(Directory.GetCurrentDirectory() + "\\Fibonacci_Matrix_Exponentiation.txt", res.c.ToString(), Encoding.UTF8);
//File.WriteAllText(Directory.GetCurrentDirectory() + "\\Fibonacci_Matrix_Exponentiation.txt", result[1, 0].ToString(), Encoding.UTF8);
//return result[1, 0];
return(res.c);
}
private static BigInteger Fibonacci_MatrixExponentiation(int n)
{
if (n == 0)
{
return(BigInteger.Zero);
}
else if (n == 1)
{
return(BigInteger.One);
}
bool isNegative = n < 0 && n % 2 == 0;
matrix2x2 res = new matrix2x2 {
a = 1, b = 0, c = 0, d = 1
};
matrix2x2 fib = new matrix2x2 {
a = 1, b = 1, c = 1, d = 0
};
n = Math.Abs(n);
do
{
if (n % 2 == 1)
{
res *= fib;
}
fib *= fib;
} while ((n /= 2) > 0);
if (isNegative)
{
res.c = -res.c;
}
return(res.c);
}
