| |
| //@HEADER |
| // ************************************************************************ |
| // |
| // HPCCG: Simple Conjugate Gradient Benchmark Code |
| // Copyright (2006) Sandia Corporation |
| // |
| // Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive |
| // license for use of this work by or on behalf of the U.S. Government. |
| // |
| // This library is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU Lesser General Public License as |
| // published by the Free Software Foundation; either version 2.1 of the |
| // License, or (at your option) any later version. |
| // |
| // This library is distributed in the hope that it will be useful, but |
| // WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| // Lesser General Public License for more details. |
| // |
| // You should have received a copy of the GNU Lesser General Public |
| // License along with this library; if not, write to the Free Software |
| // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
| // USA |
| // Questions? Contact Michael A. Heroux (maherou@sandia.gov) |
| // |
| // ************************************************************************ |
| //@HEADER |
| |
| ///////////////////////////////////////////////////////////////////////// |
| |
| // Routine to compute the dot product of two vectors where: |
| |
| // n - number of vector elements (on this processor) |
| |
| // x, y - input vectors |
| |
| // residual - pointer to scalar value, on exit will contain result. |
| |
| ///////////////////////////////////////////////////////////////////////// |
| |
| #include "ddot.hpp" |
| int ddot (const int n, const double * const x, const double * const y, |
| double * const result, double & time_allreduce) |
| { |
| double local_result = 0.0; |
| if (y==x) |
| #ifdef USING_OMP |
| #pragma omp parallel for reduction (+:local_result) |
| #endif |
| for (int i=0; i<n; i++) local_result += x[i]*x[i]; |
| else |
| #ifdef USING_OMP |
| #pragma omp parallel for reduction (+:local_result) |
| #endif |
| for (int i=0; i<n; i++) local_result += x[i]*y[i]; |
| |
| #ifdef USING_MPI |
| // Use MPI's reduce function to collect all partial sums |
| double t0 = mytimer(); |
| double global_result = 0.0; |
| MPI_Allreduce(&local_result, &global_result, 1, MPI_DOUBLE, MPI_SUM, |
| MPI_COMM_WORLD); |
| *result = global_result; |
| time_allreduce += mytimer() - t0; |
| #else |
| *result = local_result; |
| #endif |
| |
| return(0); |
| } |
