Ατζέντα εργαστηρίου Παράλληλου Προγραμματισμού 25/5/2021

README.md

Ατζέντα εργαστηρίου Παράλληλου Προγραμματισμού 25/5/2021

Στο gist αυτό θα αναρτηθούν λύσεις και υποδείξεις κατά τη διεξαγωγή του εργαστηρίου.

libtbb2 libtbb-dev libtbb2-dbg libtbb-doc tbb-examples
g++

S10-testload-serial.cpp

// Serial dummy load
// Compile with:  g++ -Wall -O2 testload-serial.cpp -o testload-serial

#include <iostream>


#define N 10000000
#define R 100

using namespace std;

void testmap(float& a) {
  for (size_t j=0;j<R;++j) {
    a = a+j;
  }
}


// Serial implementation
void ApplyMapSerial(float a[],size_t n) {
  for (size_t i=0;i<n;++i) {
    testmap(a[i]);
  }   
}


int main() {

  // alloc array
  float *a = new float[N];	// will throw exception if alloc error

  // init array
  for (size_t i=0;i<N;++i) {
    a[i] = 3.0;
  }

  // execute test load
  ApplyMapSerial(a,N);
      
  // check results
  for (size_t i=0;i<N;++i) {
    if (a[i]!=4953.0) {
      cout << "error " << a[i] << endl;
      break;  
    }
  }

  // free array
  delete[] a;	// NOTE: the syntax of freeing arrays! 

  return 0;
}

S20-testload-tbb.cpp

// Tests TBB parallel_for with dummy load
// Compile with:  g++ -Wall -O2 -std=c++11 testload-tbb.cpp -o testload-tbb -ltbb

#include <iostream>
#include "tbb/tbb.h"

#define N 10000000
#define R 100

using namespace std;

void testmap(float& a) {
  for (size_t j=0;j<R;++j) {
    a = a+j;
  }
}


// TBB implementation with lambda function
void ApplyMapTbb(float a[],size_t n) {
  tbb::parallel_for(size_t(0),n,[&](size_t i) {	// NOTE: Index params (1st,2nd) must be of same type
    testmap(a[i]);				// that is, "parallel_for(0,n,..." throws compiler error
  });
}


int main() {

  // alloc array
  float *a = new float[N];	// will throw exception if alloc error

  // init array
  for (size_t i=0;i<N;++i) {
    a[i] = 3.0;
  }

  // execute test load
  ApplyMapTbb(a,N);
      
  // check results
  for (size_t i=0;i<N;++i) {
    if (a[i]!=4953.0) {
      cout << "error " << a[i] << endl;
      break;  
    }
  }

  // free array
  delete[] a;	// NOTE: the syntax of freeing arrays! 

  return 0;
}

S25-testload-tbb2.cpp

// Tests TBB parallel_for with dummy load
// Compile with:  g++ -Wall -O2 -std=c++11 testload-tbb2.cpp -o testload-tbb2 -ltbb

#include <iostream>
#include "tbb/tbb.h"

#define N 10000000
#define R 100

using namespace std;

void testmap(float& a) {
  for (size_t j=0;j<R;++j) {
    a = a+j;
  }
}


// TBB implementation with body as a lambda function, alternative version
void ApplyMapTbb(float a[],size_t n) {
  tbb::parallel_for(tbb::blocked_range<size_t>(0,n),[&](const tbb::blocked_range<size_t>& r) {
    for (size_t i=r.begin();i!=r.end();++i) {
      testmap(a[i]);
    }
  });
}


int main() {

  // alloc array
  float *a = new float[N];	// will throw exception if alloc error

  // init array
  for (size_t i=0;i<N;++i) {
    a[i] = 3.0;
  }

  // execute test load
  ApplyMapTbb(a,N);
      
  // check results
  for (size_t i=0;i<N;++i) {
    if (a[i]!=4953.0) {
      cout << "error " << a[i] << endl;
      break;  
    }
  }

  // free array
  delete[] a;	// NOTE: the syntax of freeing arrays! 

  return 0;
}

S30-triad-serial.cpp

// Serial triad benchmark
// Compile with:  g++ -Wall -O2 triad-serial.cpp -o triad-serial

#include <iostream>


#define N 10000000
#define R 100

using namespace std;


// Serial implementation
void ApplyTriadSerial(double a[],double b[], double c[], double d[],size_t n) {
  for (size_t i=0;i<n;++i) {
    for (size_t j=0;j<R;++j) {
      a[i] = b[i]*c[i]+d[i];
    }
  }   
}


int main() {

  // alloc arrays
  double *a = new double[N];
  double *b = new double[N];
  double *c = new double[N];
  double *d = new double[N];
  
  // init arrays
  for (size_t i=0;i<N;++i) {
    a[i]=2.0*i;
    b[i]=-1.0*i;
    c[i]=i+5.0;
    d[i]=-7.0*i;
  }

  // execute test load
  ApplyTriadSerial(a,b,c,d,N);
  
  // check results
  for (size_t i=0;i<N;++i) {
    if (a[i]!=(b[i]*c[i]+d[i])) {
      cout << "error " << (b[i]*c[i]+d[i]) << ": " << a[i] << endl;
      break;  
    }
  }

  // free arrays
  delete[] a;
  delete[] b;
  delete[] c;
  delete[] d;
      
  return 0;
}

S35-partial.cpp

// TBB implementation with body as a lambda function
void ApplyTriadTbb(double a[],double b[],double c[],double d[],size_t n) {
  tbb::parallel_for(size_t(0),n,[&](size_t i) {	
    for (size_t j=0;j<R;++j) {
      a[i] = b[i]*c[i]+d[i];
    }
  });
}

S37-partial.cpp

// TBB implementation with body as a lambda function
void ApplyTriadTbb(double a[],double b[],double c[],double d[],size_t n) {
  tbb::parallel_for(tbb::blocked_range<size_t>(0,n),[&](const tbb::blocked_range<size_t>& r) {
    for (size_t i=r.begin();i!=r.end();++i) {
      for (size_t j=0;j<R;++j) {
        a[i] = b[i]*c[i]+d[i];
      }
    }
  });
}