waxpby.cpp

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//               HPCCG: Simple Conjugate Gradient Benchmark Code
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/////////////////////////////////////////////////////////////////////////

// Routine to compute the update of a vector with the sum of two 
// scaled vectors where:

// w = alpha*x + beta*y

// n - number of vector elements (on this processor)

// x, y - input vectors

// alpha, beta - scalars applied to x and y respectively.

// w - output vector.

/////////////////////////////////////////////////////////////////////////

#include "waxpby.hpp"

int waxpby (const int n, const double alpha, const double * const x, 
	    const double beta, const double * const y, 
		     double * const w)
{  
  if (alpha==1.0) {
#ifdef USING_OMP
#pragma omp parallel for
#endif
    for (int i=0; i<n; i++) w[i] = x[i] + beta * y[i];
  }
  else if(beta==1.0) {
#ifdef USING_OMP
#pragma omp parallel for
#endif
    for (int i=0; i<n; i++) w[i] = alpha * x[i] + y[i];
  }
  else {
#ifdef USING_OMP
#pragma omp parallel for
#endif
    for (int i=0; i<n; i++) w[i] = alpha * x[i] + beta * y[i];
  }

  return(0);
}