source code
/* The Computer Language Benchmarks Game
https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
contributed by Isaac Gouy
parallel by The Anh Tran
Updated by Alan McGovern
*/
using System;
using System.Threading;
class SpectralNorm
{
public class BarrierHandle : System.Threading.WaitHandle
{
int current;
int threads;
ManualResetEvent handle = new ManualResetEvent (false);
public BarrierHandle (int threads)
{
this.current = threads;
this.threads = threads;
}
public override bool WaitOne()
{
ManualResetEvent h = handle;
if (Interlocked.Decrement (ref current) > 0) {
h.WaitOne ();
}
else {
handle = new ManualResetEvent (false);
Interlocked.Exchange (ref current, threads);
h.Set ();
h.Close ();
}
return true;
}
}
public static void Main(String[] args)
{
int n = 2500;
if (args.Length > 0)
n = Int32.Parse(args[0]);
Console.WriteLine("{0:f9}", RunGame(n));
}
private static double RunGame(int n)
{
// create unit vector
double[] u = new double[n];
double[] tmp = new double[n];
double[] v = new double[n];
for (int i = 0; i < n; i++)
u[i] = 1.0;
int nthread = Environment.ProcessorCount;
BarrierHandle barrier = new BarrierHandle (nthread);
// objects contain result of each thread
Approximate[] apx = new Approximate[nthread];
// thread handle for waiting/joining
Thread[] threads = new Thread[nthread];
// create thread and hand out tasks
int chunk = n / nthread;
for (int i = 0; i < nthread; i++)
{
int r1 = i * chunk;
int r2 = (i < (nthread - 1)) ? r1 + chunk : n;
apx[i] = new Approximate(u, v, tmp, r1, r2);
apx[i].Barrier = barrier;
threads[i] = new Thread(new ThreadStart(apx[i].Evaluate));
threads[i].Start();
}
// collect results
double vBv = 0, vv = 0;
for (int i = 0; i < nthread; i++)
{
threads[i].Join();
vBv += apx[i].m_vBv;
vv += apx[i].m_vv;
}
return Math.Sqrt(vBv / vv);
}
private class Approximate
{
internal BarrierHandle? Barrier;
private double[] m_u;
private double[] m_v;
private double[] m_tmp;
private int m_range_begin, m_range_end;
public double m_vBv = 0, m_vv = 0;
public Approximate(double[] u, double[] v, double[] tmp, int rbegin, int rend)
{
m_u = u;
m_v = v;
m_tmp = tmp;
m_range_begin = rbegin;
m_range_end = rend;
}
public void Evaluate()
{
for (int i = 0; i < 10; i++)
{
MultiplyAtAv(m_u, m_tmp, m_v);
MultiplyAtAv(m_v, m_tmp, m_u);
}
for (int i = m_range_begin; i < m_range_end; i++)
{
m_vBv += m_u[i] * m_v[i];
m_vv += m_v[i] * m_v[i];
}
}
/* return element i,j of infinite matrix A */
private static double eval_A(int i, int j)
{
int div = (((i + j) * (i + j + 1) >> 1) + i + 1);
return 1.0 / div;
}
/* multiply vector v by matrix A */
private void MultiplyAv(double[] v, double[] Av)
{
for (int i = m_range_begin; i < m_range_end; i++)
{
double sum = 0.0;
for (int j = 0; j < v.Length; j++)
sum += eval_A(i, j) * v[j];
Av[i] = sum;
}
}
/* multiply vector v by matrix A transposed */
private void MultiplyAtv(double[] v, double[] Atv)
{
for (int i = m_range_begin; i < m_range_end; i++)
{
double sum = 0.0;
for (int j = 0; j < v.Length; j++)
sum += eval_A(j, i) * v[j];
Atv[i] = sum;
}
}
/* multiply vector v by matrix A and then by matrix A transposed */
private void MultiplyAtAv(double[] v, double[] tmp, double[] AtAv)
{
MultiplyAv(v, tmp);
Barrier.WaitOne ();
MultiplyAtv(tmp, AtAv);
Barrier.WaitOne ();
}
}
}
notes, command-line, and program output
NOTES:
64-bit Ubuntu quad core
.NET SDK 9.0.100
Host Version: 9.0.0
Commit: 9d5a6a9aa4
<OutputType>Exe
<TargetFramework>net9.0
<ImplicitUsings>enable
<Nullable>enable
<AllowUnsafeBlocks>true
<ServerGarbageCollection>true
<ConcurrentGarbageCollection>true
<PublishAot>false
Wed, 13 Nov 2024 23:16:30 GMT
MAKE:
cp spectralnorm.csharpcore-2.csharpcore Program.cs
cp Include/csharpcore/program.csproj .
mkdir obj
cp Include/csharpcore/project.assets.json ./obj
/opt/src/dotnet-sdk-9.0.100/dotnet build -c Release --use-current-runtime
Determining projects to restore...
/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/program.csproj : warning NU1900: Error occurred while getting package vulnerability data: Unable to load the service index for source https://api.nuget.org/v3/index.json.
Restored /home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/program.csproj (in 6.26 sec).
/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/program.csproj : warning NU1900: Error occurred while getting package vulnerability data: Unable to load the service index for source https://api.nuget.org/v3/index.json.
/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/Program.cs(167,13): warning CS8602: Dereference of a possibly null reference. [/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/program.csproj]
program -> /home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/bin/Release/net9.0/linux-x64/program.dll
Build succeeded.
/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/program.csproj : warning NU1900: Error occurred while getting package vulnerability data: Unable to load the service index for source https://api.nuget.org/v3/index.json.
/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/program.csproj : warning NU1900: Error occurred while getting package vulnerability data: Unable to load the service index for source https://api.nuget.org/v3/index.json.
/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/Program.cs(167,13): warning CS8602: Dereference of a possibly null reference. [/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/program.csproj]
3 Warning(s)
0 Error(s)
Time Elapsed 00:00:11.31
13.28s to complete and log all make actions
COMMAND LINE:
./bin/Release/net9.0/linux-x64/program 5500
PROGRAM OUTPUT:
1.274224153