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kai
2025-06-01 14:04:56 +02:00
parent 90091a8ae0
commit a4729d47f2
1 changed files with 41 additions and 89 deletions
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130
lab10/jacobi/jacobi_mpi.cpp
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@@ -47,117 +47,69 @@ Jacobi::Result JacobiMPI::run(const Matrix &init, double epsilon,
int t0 = 0; // array index of current timestep
int t1 = 1; // array index of next timestep
// Tags für MPI senden/empfangen besser konstant machen
const int TAG_UP = 0;
const int TAG_DOWN = 1;
// Globale Distanz synchronisieren
while (dist > epsilon && nIter < maxNumIter) {
dist = 0;
if (rank == 0) {
MPI_Request send_lower;
std::vector<double> send_vec_low = phi[t0].get_row(indexRowGlobalEnd);
MPI_Isend(send_vec_low.data(), numCols, MPI_DOUBLE, neighborLower,
indexRowGlobalEnd, MPI_COMM_WORLD, &send_lower);
std::vector<double> send_vec_up, send_vec_low;
MPI_Request requestLower;
MPI_Irecv(haloLower.data(), numCols, MPI_DOUBLE, neighborLower,
rowHaloLowerIndex, MPI_COMM_WORLD, &requestLower);
MPI_Request send_upper, send_lower;
MPI_Request request_upper, request_lower;
MPI_Wait(&send_lower, MPI_STATUS_IGNORE);
MPI_Wait(&requestLower, MPI_STATUS_IGNORE);
for (int i = 1; i < numRows; ++i) {
for (int j = 1; j < numCols - 1; ++j) {
double valueBottom;
(i == numRows - 1) ? valueBottom = haloLower[j]
: valueBottom = phi[t0](i + 1, j);
phi[t1](i, j) = .25 * (valueBottom + phi[t0](i - 1, j) +
phi[t0](i, j + 1) + phi[t0](i, j - 1));
const double diff = phi[t1](i, j) - phi[t0](i, j);
dist = std::max(dist, std::abs(diff));
}
}
if (rank != 0) {
send_vec_up = phi[t0].get_row(0); // oberste lokale Zeile
MPI_Isend(send_vec_up.data(), numCols, MPI_DOUBLE, neighborUpper, TAG_UP,
MPI_COMM_WORLD, &send_upper);
MPI_Irecv(haloUpper.data(), numCols, MPI_DOUBLE, neighborUpper, TAG_DOWN,
MPI_COMM_WORLD, &request_upper);
}
else if (rank == (numProc - 1)) {
MPI_Request send_upper;
std::vector<double> send_vec_up = phi[t0].get_row(indexRowGlobalStart);
MPI_Isend(send_vec_up.data(), numCols, MPI_DOUBLE, neighborUpper,
indexRowGlobalStart, MPI_COMM_WORLD, &send_upper);
MPI_Request request_upper;
MPI_Irecv(haloUpper.data(), numCols, MPI_DOUBLE, neighborUpper,
rowHaloUpperIndex, MPI_COMM_WORLD, &request_upper);
MPI_Wait(&send_upper, MPI_STATUS_IGNORE);
MPI_Wait(&request_upper, MPI_STATUS_IGNORE);
for (int i = 0; i < numRows - 1; ++i) {
for (int j = 1; j < numCols - 1; ++j) {
double valueTop;
(i == 0) ? valueTop = haloUpper[j] : valueTop = phi[t0](i - 1, j);
phi[t1](i, j) = .25 * (phi[t0](i + 1, j) + valueTop +
phi[t0](i, j + 1) + phi[t0](i, j - 1));
const double diff = phi[t1](i, j) - phi[t0](i, j);
dist = std::max(dist, std::abs(diff));
}
}
if (rank != numProc - 1) {
send_vec_low = phi[t0].get_row(numRows - 1); // unterste lokale Zeile
MPI_Isend(send_vec_low.data(), numCols, MPI_DOUBLE, neighborLower,
TAG_DOWN, MPI_COMM_WORLD, &send_lower);
MPI_Irecv(haloLower.data(), numCols, MPI_DOUBLE, neighborLower, TAG_UP,
MPI_COMM_WORLD, &request_lower);
}
else {
MPI_Request send_upper;
MPI_Request send_lower;
std::vector<double> send_vec_up = phi[t0].get_row(indexRowGlobalStart);
MPI_Isend(send_vec_up.data(), numCols, MPI_DOUBLE, neighborUpper,
indexRowGlobalStart, MPI_COMM_WORLD, &send_upper);
std::vector<double> send_vec_low = phi[t0].get_row(indexRowGlobalEnd);
MPI_Isend(send_vec_low.data(), numCols, MPI_DOUBLE, neighborLower,
indexRowGlobalEnd, MPI_COMM_WORLD, &send_lower);
MPI_Request request_upper;
MPI_Request request_lower;
MPI_Irecv(haloUpper.data(), numCols, MPI_DOUBLE, neighborUpper,
rowHaloUpperIndex, MPI_COMM_WORLD, &request_upper);
MPI_Irecv(haloLower.data(), numCols, MPI_DOUBLE, neighborLower,
rowHaloLowerIndex, MPI_COMM_WORLD, &request_lower);
if (rank != 0) {
MPI_Wait(&send_upper, MPI_STATUS_IGNORE);
MPI_Wait(&send_lower, MPI_STATUS_IGNORE);
MPI_Wait(&request_upper, MPI_STATUS_IGNORE);
}
if (rank != numProc - 1) {
MPI_Wait(&send_lower, MPI_STATUS_IGNORE);
MPI_Wait(&request_lower, MPI_STATUS_IGNORE);
}
for (int i = 0; i < numRows; ++i) {
for (int j = 1; j < numCols - 1; ++j) {
if (i == 0) {
double valueTop = haloUpper[j];
phi[t1](i, j) = .25 * (phi[t0](i + 1, j) + valueTop +
phi[t0](i, j + 1) + phi[t0](i, j - 1));
const double diff = phi[t1](i, j) - phi[t0](i, j);
dist = std::max(dist, std::abs(diff));
} else if (i == numRows - 1) {
double valueBottom = haloLower[j];
phi[t1](i, j) = .25 * (valueBottom + phi[t0](i - 1, j) +
phi[t0](i, j + 1) + phi[t0](i, j - 1));
const double diff = phi[t1](i, j) - phi[t0](i, j);
dist = std::max(dist, std::abs(diff));
} else {
phi[t1](i, j) = .25 * (phi[t0](i + 1, j) + phi[t0](i - 1, j) +
phi[t0](i, j + 1) + phi[t0](i, j - 1));
const double diff = phi[t1](i, j) - phi[t0](i, j);
dist = std::max(dist, std::abs(diff));
}
}
for (int i = 0; i < numRows; ++i) {
for (int j = 1; j < numCols - 1; ++j) {
double top = (i == 0) ? (rank == 0 ? phi[t0](i, j) : haloUpper[j])
: phi[t0](i - 1, j);
double bottom =
(i == numRows - 1)
? (rank == numProc - 1 ? phi[t0](i, j) : haloLower[j])
: phi[t0](i + 1, j);
phi[t1](i, j) =
0.25 * (top + bottom + phi[t0](i, j - 1) + phi[t0](i, j + 1));
double diff = phi[t1](i, j) - phi[t0](i, j);
dist = std::max(dist, std::abs(diff));
}
}
// Globale max-Distanz berechnen
double globalDist = 0;
MPI_Allreduce(&dist, &globalDist, 1, MPI_DOUBLE, MPI_MAX, MPI_COMM_WORLD);
dist = globalDist;
nIter++;
std::swap(t0, t1);
// if (nIter == 100) {
// std::cout << phi[t1] << std::endl;
// }
}
// std::cout << phi[t1] << std::endl;