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#include <iostream>
#include <flens/flens.cxx> using namespace flens; using namespace std; /// /// Include the SuperLu stuff for double precision. /// #include <slu_ddefs.h> /// /// Wrapper for the SuperLU solver dgssv. Looks complicated but it's actually /// pretty simple. We create SuperLU matrix wrapper for our matrices and then /// call the solver. Anyway, in future we will hide the details in FLENS. /// template <typename MA, typename PR, typename PC, typename VB> int dgssv(GeCCSMatrix<MA> &A, DenseVector<PC> &pc, DenseVector<PR> &pr, DenseVector<VB> &b) { ASSERT(pr.length()==A.numRows()); ASSERT(pc.length()==A.numCols()); superlu_options_t options; SuperLUStat_t stat; SuperMatrix _A, _L, _U, _B; dCreate_CompCol_Matrix(&_A, A.numRows(), A.numCols(), A.engine().numNonZeros(), A.engine().values().data(), A.engine().rows().data(), A.engine().cols().data(), SLU_NC, SLU_D, SLU_GE); dCreate_Dense_Matrix(&_B, b.length(), 1, b.data(), b.length(), SLU_DN, SLU_D, SLU_GE); set_default_options(&options); options.ColPerm = NATURAL; StatInit(&stat); int info; dgssv(&options, &_A, pc.data(), pr.data(), &_L, &_U, &_B, &stat, &info); Destroy_SuperMatrix_Store(&_A); Destroy_SuperMatrix_Store(&_B); Destroy_SuperNode_Matrix(&_L); Destroy_CompCol_Matrix(&_U); StatFree(&stat); return info; } int main() { /// /// SuperLU requires an index base of zero. Here we set the default index base /// of the storage scheme to zero via `IndexBaseZero`. /// typedef int IndexType; typedef IndexBaseZero<IndexType> IndexBase; typedef CoordStorage<double, CoordColRowCmp, IndexBase> Coord; /// /// Alternative we could specify it through the constructor (see class API). /// const IndexType m = 5; const IndexType n = 5; GeCoordMatrix<Coord> A_(m, n); /// /// We setup the matrix from the SuperLU user guide. So here the values. /// const double s = 19, u = 21, p = 16, e = 5, r = 18, l = 12; /// /// Matrices in coordinate storage are usually used in FEM for assembling /// the stiffness matrix. Values will be accumulated. Note that an assignment /// like 'A(2,3) = ' is not allowed. /// A_(0,0) += s; A_(1,1) += u; A_(2,2) += p; A_(3,3) += e; A_(4,4) += r; A_(1,0) += l; A_(2,1) += l; A_(4,0) += l; A_(4,1) += l; A_(0,2) += u; A_(0,3) += u; A_(3,4) += u; /// /// Convert to compressed column storage. /// GeCCSMatrix<CCS<double, IndexBase> > A = A_; /// /// Just for curiosity: Compare the two formats. /// std::cout << "A_ = " << A_ << endl; std::cout << "A = " << A << endl; /// /// Setup the right-hand side $b$. We set all values to $1$. /// DenseVector<Array<double, IndexBase> > b(m); b = 1; /// /// Call the SuperLU solver for solving $Ax = b$. Note that on exit $b$ is /// overwritten with the solution $x$. /// DenseVector<Array<IndexType, IndexBase> > pr(m), pc(n); int info = dgssv(A, pr, pc, b); /// /// Check the info code /// if (info==0) { cout << "x = " << b << endl; } else { cout << "SuperLU dgssv: info = " << info << endl; } return info; } |