Re: OpenMP + ACLiC

From: OKUMURA, Akira <oxon_at_astro.isas.jaxa.jp>
Date: Wed, 15 Sep 2010 09:25:33 -0700

Hello Philippe,

Thanks for the advise. But I still get the same error.

#include <omp.h>
#include <time.h>
#include <iostream>

void pi()
{
  const Int_t kN = 100000000;
  long double top = 0.L;
  long double bottom = 0.L;
  long double kStep = 1.L/kN;
  long double sum = 0.L;

#ifndef __CINT__
#pragma omp parallel private(top, bottom)
#endif

  {
#ifndef __CINT__
#pragma omp for reduction(+:sum)
#endif

    for(Int_t i = 0; i < kN; i++) {

      top = 4.L/(1.L + (kStep*i)*(kStep*i));
      bottom = 4.L/(1.L + (kStep*(i+1))*(kStep*(i + 1)));
      sum += (top + bottom)*kStep/2.L;

    } // i
  }
  std::cout.precision(16);
  std::cout << "pi = " << sum << "\n";
}

root [4] .L pi.C++
Info in <TUnixSystem::ACLiC>: creating shared library /Users/oxon/./pi_C.so In file included from /Users/oxon/pi_C_ACLiC_dict.h:34,

                 from /Users/oxon/pi_C_ACLiC_dict.cxx:16:

/Users/oxon/./pi.C: In function ‘void pi()’: /Users/oxon/./pi.C:14: error: expected ‘#pragma omp’ clause before ‘public’ i686-apple-darwin10-g++-4.2.1: /Users/oxon/pi_C_ACLiC_dict.o: No such file or directory Error in <ACLiC>: Compilation failed!

Regards,

--
OKUMURA, Akira oxon@{astro.isas.jaxa.jp,stanford.edu}
Institute of Space and Astronautical Science (ISAS/JAXA)
Now at KIPAC/SLAC/Stanford
Varian Physics #306
382 Via Pueblo Mall, MC 406 Stanford, CA94305
TEL 650-736-0971/FAX 650-724-5065
Skype : okumura.akira

On 2010/09/15, at 8:53, Philippe Canal wrote:

> Hi,
> 
> You need to at least hide the #pragma from CINT:
> 
> #ifndef __CINT__
> #pragma omp parallel private(top, bottom)
> #endif
> {
> #ifndef __CINT__
> #pragma omp for reduction(+:sum)
> #endif
> for(Int_t i = 0; i < kN; i++) {
> 
> Cheers,
> Philippe.
> 
> On 9/15/10 10:47 AM, OKUMURA, Akira wrote:
>> Hello ROOTers,
>> 
>> Does ACLiC support OpenMP?
>> 
>> I started learning OpenMP to improve the speed of my analysis. The following is an example to calculate pi with OpenMP.
>> 	
>> === pi.C ===
>> #include <omp.h>
>> #include <time.h>
>> #include <iostream>
>> 
>> void pi()
>> {
>>  const Int_t kN = 100000000;
>>  long double top = 0.L;
>>  long double bottom = 0.L;
>>  long double kStep = 1.L/kN;
>>  long double sum = 0.L;
>> 
>> #pragma omp parallel private(top, bottom)
>>  {
>> #pragma omp for reduction(+:sum)
>>    for(Int_t i = 0; i < kN; i++) {
>>      top = 4.L/(1.L + (kStep*i)*(kStep*i));
>>      bottom = 4.L/(1.L + (kStep*(i+1))*(kStep*(i + 1)));
>>      sum += (top + bottom)*kStep/2.L;
>>    } // i
>>  }
>>  std::cout.precision(16);
>>  std::cout << "pi = " << sum << "\n";
>> }
>> ============
>> 
>> But I got the following error.
>> ============
>> root [0] gSystem->SetIncludePath("-fopenmp")
>> root [1] gSystem->AddLinkedLibs("-lgomp")
>> root [2] .L pi.C+O
>> Info in <TUnixSystem::ACLiC>: creating shared library /Users/oxon/./pi_C.so
>> In file included from /Users/oxon/pi_C_ACLiC_dict.h:34,
>>                 from /Users/oxon/pi_C_ACLiC_dict.cxx:16:
>> /Users/oxon/./pi.C: In function ‘void pi()’:
>> /Users/oxon/./pi.C:13: error: expected ‘#pragma omp’ clause before ‘public’
>> i686-apple-darwin10-g++-4.2.1: /Users/oxon/pi_C_ACLiC_dict.o: No such file or directory
>> Error in <ACLiC>: Compilation failed!
>> ============
>> 
>> It seems that some of OpenMP words are not handled properly in generation of a dictionary. I suppose ACLiC does not support OpenMP yet.
>> 
>> If ACLiC supports OpenMP, how can I run the script in ROOT? This example runs as I expected in standalone C++ program.
>> 
>> I am using ROOT trunk and GCC (i686-apple-darwin10-g++-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5664)) on Snow Leopard.
>> 
>> Regards,
>> 
>> --
>> OKUMURA, Akira oxon@{astro.isas.jaxa.jp,stanford.edu}
>> Institute of Space and Astronautical Science (ISAS/JAXA)
>> Now at KIPAC/SLAC/Stanford
>> Varian Physics #306
>> 382 Via Pueblo Mall, MC 406 Stanford, CA94305
>> TEL 650-736-0971/FAX 650-724-5065
>> Skype : okumura.akira
>> 

Received on Wed Sep 15 2010 - 18:25:45 CEST