static void Main(string[] args)
{
/* Compare the time it takes to diagonalize a matrix
* of size n by different methods:
* Cyclic jacobi, value-by-value and v-b-v
* for both highest and lowest eig val.
*/
Stopwatch sw = new Stopwatch();
foreach (string arg in args)
{
int n = Int32.Parse(arg);
// Generate symmetric nxn matrix A
matrix A = randomMatrix(n, n);
restoreUpperTriang(A);
// Cyclic jacobi
matrix V = new matrix(n, n);
vector e = new vector(n);
sw.Start();
int sweeps = Jacobi.cyclic(A, V, e);
sw.Stop();
double cyclic = sw.Elapsed.Ticks / 10000.0;
sw.Reset();
// Value-by-value full
V = new matrix(n, n);
e = new vector(n);
sw.Start();
vector eigVals = Jacobi.lowestK(A, V, e, n);
sw.Stop();
double VBVfull = sw.Elapsed.Ticks / 10000.0;
sw.Reset();
// Value-by-value 1
V = new matrix(n, n);
e = new vector(n);
sw.Start();
eigVals = Jacobi.lowestK(A, V, e, 1);
sw.Stop();
double VBVlow = sw.Elapsed.Ticks / 10000.0;
sw.Reset();
// Value-by-value 1, highest first
V = new matrix(n, n);
e = new vector(n);
sw.Start();
eigVals = Jacobi.highestK(A, V, e, 1);
sw.Stop();
double VBVhigh = sw.Elapsed.Ticks / 10000.0;
sw.Reset();
// size of matrix and time in ms
WriteLine($"{n} {cyclic} {VBVfull} {VBVlow} {VBVhigh}");
}
}
static void Main()
{
int n = 6;
WriteLine($"Generate symmetric {n}x{n} matrix A");
matrix A = randomMatrix(n, n);
restoreUpperTriang(A);
A.print("A: ");
matrix V = new matrix(n, n);
vector e = new vector(n);
int sweeps;
// Cyclic
sweeps = Jacobi.cyclic(A, V, e);
WriteLine($"Cyclic Jacobi done in {sweeps} sweeps");
e.print("Cyclic eigenvalues: ");
// Lowest k
restoreUpperTriang(A);
V = new matrix(n, n);
e = new vector(n);
int k = n / 3;
vector v = Jacobi.lowestK(A, V, e, k);
v.print($"Lowest {k} values:");
A.print($"Test that {k} rows are cleared");
// Highest k
restoreUpperTriang(A);
V = new matrix(n, n);
e = new vector(n);
k = n / 3;
v = Jacobi.highestK(A, V, e, k);
v.print($"Highest {k} values:");
A.print($"Test that {k} rows are cleared");
restoreUpperTriang(A);
V = new matrix(n, n);
e = new vector(n);
int rots = Jacobi.classic(A, V, e);
e.print($"Classical done! rotations: {rots}");
A.print($"Test that all rows are cleared");
}
