7.1.5.1.4 : Le main_vector.cpp
First, we have to include the appropriate files :

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#include <vector>
#include <iostream>


Then, we define our hadamard kernel :

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///Do the Hadamard product
/**	@param[out] tabResult : table of results of tabX*tabY
 * 	@param tabX : input table
 * 	@param tabY : input table
 * 	@param nbElement : number of elements in the tables
*/
void hadamard_product(float* tabResult, const float* tabX, const float* tabY, long unsigned int nbElement){
	for(long unsigned int i(0lu); i < nbElement; ++i){
		tabResult[i] = tabX[i]*tabY[i];
	}
}


We add the function to evaluate our kernel :

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///Get the number of cycles per elements of the Hadamard product
/**	@param nbElement : number of elements of the tables
 * 	@param nbRepetition : number of repetition to evaluate the function hadamard_product
*/
void evaluateHadamardProduct(long unsigned int nbElement, long unsigned int nbRepetition){
	//Allocation of the tables
	std::vector<float> vecResult(nbElement), vecX(nbElement), vecY(nbElement);
	//Initialisation of the tables
	for(long unsigned int i(0lu); i < nbElement; ++i){
		vecX[i] = (float)(i*32lu%17lu);
		vecY[i] = (float)(i*57lu%31lu);
	}
	float res(0.0f);
	//Stating the timer
	long unsigned int beginTime(rdtsc());
	for(long unsigned int i(0lu); i < nbRepetition; ++i){
		hadamard_product(tabResult, vecX.data(), vecY.data(), nbElement);
		res += vecResult[0];
	}
	//Get the time of the nbRepetition calls
	long unsigned int elapsedTime((double)(rdtsc() - beginTime)/((double)nbRepetition));
	
	double cyclePerElement(((double)elapsedTime)/((double)nbElement));
	std::cout << "evaluateHadamardProduct : nbElement = "<<nbElement<<", cyclePerElement = " << cyclePerElement << " cy/el, elapsedTime = " << elapsedTime << " cy, res = " << res << std::endl;
	std::cerr << nbElement << "\t" << cyclePerElement << "\t" << elapsedTime << std::endl;
}


Finally, we call the function to evaluate several points in order to make plots :

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int main(int argc, char** argv){
	std::cout << "Hadamard product vector" << std::endl;
	evaluateHadamardProduct(1000lu, 1000000lu);
	evaluateHadamardProduct(2000lu, 1000000lu);
	evaluateHadamardProduct(3000lu, 1000000lu);
	evaluateHadamardProduct(5000lu, 1000000lu);
	evaluateHadamardProduct(10000lu, 1000000lu);
	return 0;
}


Le main_vector.cpp complet : 
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/***************************************
	Auteur : Pierre Aubert
	Mail : pierre.aubert@lapp.in2p3.fr
	Licence : CeCILL-C
****************************************/

#include <vector>
#include <iostream>

///Do the Hadamard product
/**	@param[out] tabResult : table of results of tabX*tabY
 * 	@param tabX : input table
 * 	@param tabY : input table
 * 	@param nbElement : number of elements in the tables
*/
void hadamard_product(float* tabResult, const float* tabX, const float* tabY, long unsigned int nbElement){
	for(long unsigned int i(0lu); i < nbElement; ++i){
		tabResult[i] = tabX[i]*tabY[i];
	}
}

///Get the number of cycles per elements of the Hadamard product
/**	@param nbElement : number of elements of the tables
 * 	@param nbRepetition : number of repetition to evaluate the function hadamard_product
*/
void evaluateHadamardProduct(long unsigned int nbElement, long unsigned int nbRepetition){
	//Allocation of the tables
	std::vector<float> vecResult(nbElement), vecX(nbElement), vecY(nbElement);
	//Initialisation of the tables
	for(long unsigned int i(0lu); i < nbElement; ++i){
		vecX[i] = (float)(i*32lu%17lu);
		vecY[i] = (float)(i*57lu%31lu);
	}
	float res(0.0f);
	//Stating the timer
	long unsigned int beginTime(rdtsc());
	for(long unsigned int i(0lu); i < nbRepetition; ++i){
		hadamard_product(tabResult, vecX.data(), vecY.data(), nbElement);
		res += vecResult[0];
	}
	//Get the time of the nbRepetition calls
	long unsigned int elapsedTime((double)(rdtsc() - beginTime)/((double)nbRepetition));
	
	double cyclePerElement(((double)elapsedTime)/((double)nbElement));
	std::cout << "evaluateHadamardProduct : nbElement = "<<nbElement<<", cyclePerElement = " << cyclePerElement << " cy/el, elapsedTime = " << elapsedTime << " cy, res = " << res << std::endl;
	std::cerr << nbElement << "\t" << cyclePerElement << "\t" << elapsedTime << std::endl;
}

int main(int argc, char** argv){
	std::cout << "Hadamard product vector" << std::endl;
	evaluateHadamardProduct(1000lu, 1000000lu);
	evaluateHadamardProduct(2000lu, 1000000lu);
	evaluateHadamardProduct(3000lu, 1000000lu);
	evaluateHadamardProduct(5000lu, 1000000lu);
	evaluateHadamardProduct(10000lu, 1000000lu);
	return 0;
}
Le fichier main_vector.cpp est disponible ici.