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R12662/poisson_wip/simulation_sendrecv.cc
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simulation_sendrecv.cc
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/* -------------------------------------------------------------------------- */
#include "simulation.hh"
/* -------------------------------------------------------------------------- */
#include <cmath>
#include <iostream>
#include <mpi.h>
#include <vector>
/* -------------------------------------------------------------------------- */
/* -------------------------------------------------------------------------- */
Simulation::Simulation(int m, int n, int n_iter, int prank, int psize)
: m_global_m(m), m_global_n(n), m_n_iter(n_iter), m_h_m(1. / m),
m_h_n(1. / n), m_grids(m, n), m_f(m, n),
m_dumper(new DumperASCII(m_grids.old())), m_prank(prank), m_psize(psize) {}
/* -------------------------------------------------------------------------- */
void Simulation::set_initial_conditions() {
for (int i = 0; i < m_global_m; i++) {
for (int j = 0; j < m_global_n; j++) {
m_f(i, j) = -2. * 100. * M_PI * M_PI * std::sin(10. * M_PI * ( i + (int)(m_prank*m_global_n/m_psize)) * m_h_m) *
std::sin(10. * M_PI * j * m_h_n);
} // assuming square global problem size
}
}
/* -------------------------------------------------------------------------- */
std::tuple<float, int> Simulation::compute() {
int s = 0;
float l2 = 0;
int next = m_prank+1;
int prev = m_prank-1;
do {
/// Compute step
l2 = compute_step();
//std::cout << "Process " << m_prank << " just computed iteration " << s << std::endl << std::flush;
/// Launch communications
Grid & u = m_grids.current();
/* ATTEMPTED SYNCHRONOUS VERSION */
// Exchange information with block above (unless you're the first block)
if (m_prank > 0){
// Prepare send, recieve buffers
float *send = 0;
float *recv = 0;
send = new float [m_global_n];
recv = new float [m_global_n];
for (int i = 0; i < m_global_n; i++) {
send[i] = u(1, 0);
}
// Send/recieve buffer content
MPI_Sendrecv(send, m_global_n, MPI_FLOAT, prev, 13,
recv, m_global_n, MPI_FLOAT, prev, 13,
MPI_COMM_WORLD, MPI_STATUS_IGNORE);
//Accept data
for (int i = 0; i < m_global_n; i++) {
u(0, i) = recv[i];
}
// Deallocate used memory
delete [] send;
delete [] recv;
}
// Exchange information with block below (unless you're the last block)
if (m_prank < m_psize - 1){
// Prepare send, recieve buffers
float *send = 0;
float *recv = 0;
send = new float [m_global_n];
recv = new float [m_global_n];
for (int i = 0; i < m_global_n; i++) {
send[i] = u(m_global_m-2, i);
std::cout << "OUT: " << send[i] << " ";
}
std::cout << std::endl << std::flush;
// Send/recieve buffer content
MPI_Sendrecv(send, m_global_n, MPI_FLOAT, next, 13,
recv, m_global_n, MPI_FLOAT, next, 13,
MPI_COMM_WORLD, MPI_STATUS_IGNORE);
// Accept data
for (int i = 0; i < m_global_n; i++) {
u(m_global_m-1, i) = recv[i];
std::cout << "IN " << recv[i] << " ";
}
// Deallocate used memory
delete [] send;
delete [] recv;
}
m_grids.swap();
++s;
} while (s < m_n_iter);
return std::make_tuple(l2, s);
}
/* -------------------------------------------------------------------------- */
float Simulation::compute_step() {
float l2 = 0.;
Grid & u = m_grids.current();
Grid & uo = m_grids.old();
for (int i = 1; i < m_global_m - 1; i++) {
for (int j = 1; j < m_global_n - 1; j++) {
// computation of the new step
u(i, j) = 0.25 * (uo(i - 1, j) + uo(i + 1, j) + uo(i, j - 1) +
uo(i, j + 1) - m_f(i, j) * m_h_m * m_h_n);
// L2 norm
l2 += (uo(i, j) - u(i, j)) * (uo(i, j) - u(i, j));
}
}
return l2;
}
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