Last update: 04/13/2005

Serial job example

This example runs a single process on one CPU to sum a set of 1,000,000 exponentials. It consists of four parts:

A script for the LSF batch subsystem that submits the job to lightning
Fortran code that runs the example
C code that runs the same example
C++ code that runs the same example

To run this example, you have two choices:

In the /usr/local/examples/lsf/batch/ directory on lightning:
cp serial.* $PWD
Submit the example codes to the LSF batch subsystem by entering:
bsub < serial.lsf
Copy the codes on this page and paste them into your own files:

Copy the LSF batch job script below and paste it into a file named serial.lsf in your working directory on lightning.

Copy the Fortran code below and paste it into a file named serial.f in your working directory on lightning.

Copy the C code below and paste it into a file named serial.c in your working directory on lightning.

Copy the C++ code below and paste it into a file named serial.cc in your working directory on lightning.

Submit the example codes to the LSF batch subsystem by entering:
bsub < serial.lsf

Studying this example will help you prepare your own serial jobs for submittal to lightning via LSF.

LSF batch job script to submit the serial job

#!/bin/ksh
#
# LSF batch script to run the serial code examples
#
#BSUB -n 1                              # number of tasks
#BSUB -o seriallsf.out                  # output filename
#BSUB -e seriallsf.err                  # input filename
#BSUB -J seriallsf.test                 # job name
#BSUB -q regular                        # queue

# Fortran example
pgf90 -Mextend -o serial_f -Mextend serial.f
./serial_f
rm serial_f

# C example
pgcc -o serial_c serial.c
./serial_c
rm serial_c

# C++ example
pgCC  --no_auto_instantiation -o serial_cc serial.cc
./serial_cc
rm serial_cc

Serial example code in Fortran

      program main
      implicit none
      integer i
      integer hz, clock0, clock1, t
      real(kind=8):: sum, elapsed

      sum=0.0
      call system_clock(count_rate = hz)
      call system_clock(count = clock0)
      do i=1,1000000
         sum=sum+exp(.00000001*i)
      end do
      call system_clock(count = clock1)
      elapsed = real(clock1 - clock0) / hz
      print 10, sum, elapsed
10    format(' f90 Serial Results: Sum = ',1pe12.6,' Loop time =  ',0pf12.8)
      stop
      end

Serial example code in C

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
main()
{
        int i;
        double sum, elapsed, rtc();

        elapsed=rtc();
        for(i=1; i<1000000; i++)
        {
                sum += exp( .00000001 * (double)i );
        }
        elapsed=rtc()-elapsed;

        printf( "   c Serial Results: Sum = %11e Loop time = %8f  \n",sum,elapsed );

        exit (0);
}
double rtc()
{
        struct timeval time;
        gettimeofday(&time,NULL);
        return ( (double)(time.tv_sec*1000000+time.tv_usec)/1000000 );
}

Serial example code in C++

#include <iostream>
#include <string>
#include <math.h>
#include <sys/time.h>
using namespace std;

//------ Class Defs-----------------------------------------------------
class exp_sum {
public:
        double elapsed;
        double sum();
private:
        double summer;
        struct timeval time;
        double rtc();
};
double exp_sum::sum()
{
        int i;
        summer=0.0;
        elapsed=rtc();
        for(i=1; i<1000000; i++)
        {
                summer += exp( .00000001 * (double)i );
        }
        elapsed=rtc()-elapsed;
        return summer;
};
double exp_sum:: rtc()
{
        gettimeofday(&time,NULL);
        return ( (double)(time.tv_sec*1000000+time.tv_usec)/1000000 );
};
//-----------------------------------------------------------------------


//----------MAIN  Program--------------------------------------------------
int main()
{
        exp_sum total;
        double value;
        value=total.sum();

        cout << " CC Serial Results: Sum = " << value << " Loop time =  " << total.elapsed << endl;

};

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