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Use std::find and added comments

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tqiu 2021-01-18 17:10:46 +01:00
parent a8e524fc9d
commit 123e3fa89e
1 changed files with 57 additions and 37 deletions
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opm/simulators/linalg/bda/BILU0.cpp
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@ -238,80 +238,100 @@ namespace bda
double *Ltmp = new double[Lmat->nnzbs * block_size * block_size]; double *Ltmp = new double[Lmat->nnzbs * block_size * block_size];
for (int sweep = 0; sweep < num_sweeps; ++sweep) { for (int sweep = 0; sweep < num_sweeps; ++sweep) {
// algorithm
// for every block in A (LUmat):
// if i > j:
// Lij = (Aij - sum k=1 to j-1 {Lik*Ukj}) / Ujj
// else:
// Uij = (Aij - sum k=1 to i-1 {Lik*Ukj})
// for every row // for every row
for (int row = 0; row < Nb; row++) { for (int row = 0; row < Nb; row++) {
// update U // update U
// Uij = (Aij - sum k=1 to i-1 {Lik*Ukj})
int jColStart = Ut->rowPointers[row]; int jColStart = Ut->rowPointers[row];
int jColEnd = Ut->rowPointers[row + 1]; int jColEnd = Ut->rowPointers[row + 1];
int colU = row; // rename for clarity, next row in Ut means next col in U
// for every block in this row // for every block in this row
for (int ij = jColStart; ij < jColEnd; ij++) { for (int ij = jColStart; ij < jColEnd; ij++) {
int col = Ut->colIndices[ij]; int rowU1 = Ut->colIndices[ij]; // actually rowIndices for U
// refine Uij element (or diagonal) // refine Uij element (or diagonal)
int i1 = LUmat->rowPointers[col]; int i1 = LUmat->rowPointers[rowU1];
int i2 = LUmat->rowPointers[col+1]; int i2 = LUmat->rowPointers[rowU1+1];
int kk = 0;
for(kk = i1; kk < i2; ++kk) { // search on row rowU1, find blockIndex in LUmat of block with same col (colU) as Uij
ptrdiff_t c = LUmat->colIndices[kk]; // LUmat->nnzValues[kk] is block Aij
if (c >= row) { auto candidate = std::find(LUmat->colIndices + i1, LUmat->colIndices + i2, colU);
break; assert(candidate != LUmat->colIndices + i2);
} auto kk = candidate - LUmat->colIndices;
}
double aij[bs*bs]; double aij[bs*bs];
// copy block to Aij so operations can be done on it without affecting LUmat
memcpy(&aij[0], LUmat->nnzValues + kk * bs * bs, sizeof(double) * bs * bs); memcpy(&aij[0], LUmat->nnzValues + kk * bs * bs, sizeof(double) * bs * bs);
int jk = Lmat->rowPointers[col];
int ik = (jk < Lmat->rowPointers[col+1]) ? Lmat->colIndices[jk] : Nb;
for (int k = jColStart; k < ij; ++k) { int jk = Lmat->rowPointers[rowU1]; // points to row rowU1 in L
int ki = Ut->colIndices[k]; // if row rowU1 is empty, skip row
while (ik < ki) { if (jk < Lmat->rowPointers[rowU1+1]) {
++jk; int colL = Lmat->colIndices[jk];
ik = Lmat->colIndices[jk]; for (int k = jColStart; k < ij; ++k) {
} int rowU2 = Ut->colIndices[k];
if (ik == ki) { while (colL < rowU2) {
blockMultSub<bs>(&aij[0], Lmat->nnzValues + jk * bs * bs, Ut->nnzValues + k * bs * bs); ++jk; // check next block on row rowU1 of L
colL = Lmat->colIndices[jk];
}
if (colL == rowU2) {
// Aij -= (Lik * Ukj)
blockMultSub<bs>(&aij[0], Lmat->nnzValues + jk * bs * bs, Ut->nnzValues + k * bs * bs);
}
} }
} }
// Uij_new = Aij - sum
memcpy(Utmp + ij * bs * bs, &aij[0], sizeof(double) * bs * bs); memcpy(Utmp + ij * bs * bs, &aij[0], sizeof(double) * bs * bs);
} }
// update L // update L
// Lij = (Aij - sum k=1 to j-1 {Lik*Ukj}) / Ujj
int iRowStart = Lmat->rowPointers[row]; int iRowStart = Lmat->rowPointers[row];
int iRowEnd = Lmat->rowPointers[row + 1]; int iRowEnd = Lmat->rowPointers[row + 1];
for (int ij = iRowStart; ij < iRowEnd; ij++) { for (int ij = iRowStart; ij < iRowEnd; ij++) {
int j = Lmat->colIndices[ij]; int j = Lmat->colIndices[ij];
// refine Lij element // refine Lij element
// search on row 'row', find blockIndex in LUmat of block with same col (j) as Lij
// LUmat->nnzValues[kk] is block Aij
int i1 = LUmat->rowPointers[row]; int i1 = LUmat->rowPointers[row];
int i2 = LUmat->rowPointers[row+1]; int i2 = LUmat->rowPointers[row+1];
int kk = 0;
for(kk = i1; kk < i2; ++kk) { auto candidate = std::find(LUmat->colIndices + i1, LUmat->colIndices + i2, j);
ptrdiff_t c = LUmat->colIndices[kk]; assert(candidate != LUmat->colIndices + i2);
if (c >= j) { auto kk = candidate - LUmat->colIndices;
break;
}
}
double aij[bs*bs]; double aij[bs*bs];
// copy block to Aij so operations can be done on it without affecting LUmat
memcpy(&aij[0], LUmat->nnzValues + kk * bs * bs, sizeof(double) * bs * bs); memcpy(&aij[0], LUmat->nnzValues + kk * bs * bs, sizeof(double) * bs * bs);
int jk = Ut->rowPointers[j];
int ik = Ut->colIndices[jk]; int jk = Ut->rowPointers[j]; // actually colPointers, jk points to col j in U
int rowU = Ut->colIndices[jk]; // actually rowIndices, rowU is the row of block jk
// check if L has a matching block where colL == rowU
for (int k = iRowStart; k < ij; ++k) { for (int k = iRowStart; k < ij; ++k) {
int ki = Lmat->colIndices[k]; int colL = Lmat->colIndices[k];
while(ik < ki) { while (rowU < colL) {
++jk; ++jk; // check next block on col j of U
ik = Ut->colIndices[jk]; rowU = Ut->colIndices[jk];
} }
if(ik == ki) { if (rowU == colL) {
// Aij -= (Lik * Ukj)
blockMultSub<bs>(&aij[0], Lmat->nnzValues + k * bs * bs , Ut->nnzValues + jk * bs * bs); blockMultSub<bs>(&aij[0], Lmat->nnzValues + k * bs * bs , Ut->nnzValues + jk * bs * bs);
} }
} }
// calculate aij / ujj
// calculate (Aij - sum) / Ujj
double ujj[bs*bs]; double ujj[bs*bs];
inverter(Ut->nnzValues + (Ut->rowPointers[j+1] - 1) * bs * bs, &ujj[0]); inverter(Ut->nnzValues + (Ut->rowPointers[j+1] - 1) * bs * bs, &ujj[0]);
// lij = aij / ujj // Lij_new = (Aij - sum) / Ujj
blockMult<bs>(&aij[0], &ujj[0], Ltmp + ij * bs * bs); blockMult<bs>(&aij[0], &ujj[0], Ltmp + ij * bs * bs);
} }
} }
// 1st sweep writes to Ltmp // 1st sweep writes to Ltmp