// do all the work on 'np' partitions, 'nx' data points each, for 'nt'
// time steps
space do_work(std::size_t np, std::size_t nx, std::size_t nt)
{
// U[t][i] is the state of position i at time t.
std::vector<space> U(2);
for (space& s: U)
s.resize(np);
// Initial conditions: f(0, i) = i
# pragma omp parallel
{
// Visual Studio requires OMP loop variables to be signed :/
# pragma omp for schedule(static)
for (boost::int64_t i = 0; i < (boost::int64_t)np; ++i)
U[0][i] = partition_data(nx, double(i));
// Actual time step loop
for (std::size_t t = 0; t != nt; ++t)
{
space const& current = U[t % 2];
space& next = U[(t + 1) % 2];
// Visual Studio requires OMP loop variables to be signed :/
# pragma omp for schedule(static)
for (boost::int64_t i = 0; i < (boost::int64_t)np; ++i)
next[i] = heat_part(current[idx(i-1, np)], current[i], current[idx(i+1, np)]);
}
}
// Return the solution at time-step 'nt'.
return U[nt % 2];
}
int main ( int argc, char *argv[] )
/******************************************************************************/
{
double a = 0.0;
double b = 1.0;
int i;
int id;
int n;
int p;
double x_max;
double x_min;
/*
Startup:
*/
MPI_Init ( &argc, &argv );
MPI_Comm_rank ( MPI_COMM_WORLD, &id );
MPI_Comm_size ( MPI_COMM_WORLD, &p );
/*
Determine the portion of [A,B] to be assigned to processor ID.
*/
n = 12;
i = 0;
x_min = ( ( double )( p * n + 1 - id * n - i ) * a
+ ( double )( id * n + i ) * b )
/ ( double ) ( p * n + 1 );
i = n + 1;
x_max = ( ( double )( p * n + 1 - id * n - i ) * a
+ ( double )( id * n + i ) * b )
/ ( double )( p * n + 1 );
heat_part ( n, p, id, x_min, x_max );
/*
Shut down.
*/
MPI_Finalize ( );
return p;
}
// do all the work on 'np' partitions, 'nx' data points each, for 'nt'
// time steps
space do_work(std::size_t np, std::size_t nx, std::size_t nt)
{
// U[t][i] is the state of position i at time t.
std::vector<space> U(2);
for (space& s: U)
s.resize(np);
// Initial conditions: f(0, i) = i
for (std::size_t i = 0; i != np; ++i)
U[0][i] = partition_data(nx, double(i));
// Actual time step loop
for (std::size_t t = 0; t != nt; ++t)
{
space const& current = U[t % 2];
space& next = U[(t + 1) % 2];
for (std::size_t i = 0; i != np; ++i)
next[i] = heat_part(current[idx(i, -1, np)], current[i], current[idx(i, +1, np)]);
}
// Return the solution at time-step 'nt'.
return U[nt % 2];
}
