[gridrpc-wg] Re: saga update... (iii)

18 Mar 2006

      Ok, lets do the async call, again with an example taken from
the NinfG tutorial (pi_client_multi.c, attached with changed
indentation).  The SAGA version, again in C++, is below:

-----------------------------------------------------------
#include <saga.hpp>

string func_name   = "pi/pi_trial";
string config_file = "file:///client.conf";

int main (int argc, char *argv[])
{
  if ( argc < 3 )
  {
    std::cout << "\n\t";
    std::cout << "USAGE: " << argv[0] << " TIMES HOSTNAME\n";
    std::cout << "USAGE: " << argv[0] << " TIMES HOSTNAME1 HOSTANME2...\n\n";
    exit (2);
  }

  // initialize vars from CL arguments
  int  n     = argc - 2;
  long times = atol (argv[1]) / n;

  std::vector <std::string> hosts;

  for ( int i = 0; i < n; i++ )
  {
    hosts[i] = (argv[i+2]);
  }

  try 
  {
    std::vector <long>   count;
    saga::task_container tc;

    for ( int i = 0; i < n; i++ )
    {
      // create rpc handle
      saga::rpc  handle (hosts[i], func_name, config_file);

      // perform async call
      saga::task t = handle.call <saga::async> (i, times, &count[i]);

      // add task to task container
      tc.add (t);
    }

    // wait tasks (for ever, for all)
    tc.wait (-1.0, saga::task::All);

    // Compute and display pi.
    int sum = 0;
    for ( i = 0; i < n; i++ )
    {
      sum += count[i];
    }

    std::cout << "PI = " 
              << 4.0 * (sum / ((double) times * n)))
              << std::endl;
  }
  catch ( const saga::exception & e )
  {
    std::cerr << "Found saga error: " 
              << e.what () 
              << std::endl;
    exit (2);
  }

  return (0);
}
-----------------------------------------------------------

I realised that I forgot the config_file argument to the
handle creation in the last (synchroneous) example - it
should look like above.  That actually _is_ a difference to
GridRPC: as the session in SAGA is not RPC specific, it
makes no sense to have a RPC specific config file for a
session.  Hence, the config file would need to be attached
to the handle creation.

The example code above lives from the task container: that
allows to collect multiple asynchroneous calls to be handled
together.  

Best regards, 

  Andre.

PS.: as a side note, we do have the above form of RPC
included in our saga reference implementation. However, 
it does not yet forward the calls to a NinfG or GridSolve
adaptor.  If anyone in this group has interest in connecting
the reference implementation to a real GridRPC backend,
please let us know :-)

-- 
"So much time, so little to do..."  -- Garfield

[gridrpc-wg] Re: saga update... (iii)

Andre Merzky