static void
read(CrsMatrixType &A, std::ifstream &file) {
// static_assert( Kokkos::Impl::is_same<
// typename CrsMatrixType::space_type,
// Kokkos::HostSpace
// >::value,
// "Space type of the input should be HostSpace" );
typedef typename CrsMatrixType::value_type value_type;
typedef typename CrsMatrixType::ordinal_type ordinal_type;
typedef typename CrsMatrixType::size_type size_type;
// coordinate format
typedef Coo<ordinal_type,value_type> ijv_type;
//typedef typename CrsMatrixType::space_type space_type;
//typedef Kokkos::RangePolicy<space_type,Kokkos::Schedule<Kokkos::Static> > range_policy_type;
ordinal_type m, n;
size_type nnz;
std::vector<ijv_type> mm;
const ordinal_type mm_base = 1;
{
std::string header;
if (file.is_open()) {
std::getline(file, header);
while (file.good()) {
char c = file.peek();
if (c == '%' || c == '\n') {
file.ignore(256, '\n');
continue;
}
break;
}
} else {
TACHO_TEST_FOR_ABORT(true, MSG_INVALID_INPUT(file));
}
// check the header
bool symmetry = (header.find("symmetric") != std::string::npos);
// read matrix specification
file >> m >> n >> nnz;
mm.reserve(nnz*(symmetry ? 2 : 1));
for (size_type i=0;i<nnz;++i) {
ordinal_type row, col;
value_type val;
file >> row >> col >> val;
row -= mm_base;
col -= mm_base;
mm.push_back(ijv_type(row, col, val));
if (symmetry && row != col)
mm.push_back(ijv_type(col, row, val));
}
// sort by row major order
std::sort(mm.begin(), mm.end(), std::less<ijv_type>());
}
// change mm to crs
std::vector<size_type> ap;
std::vector<ordinal_type> aj;
std::vector<value_type> ax;
ap.reserve(m+1);
aj.reserve(nnz);
ax.reserve(nnz);
{
ordinal_type ii = 0;
size_type jj = 0;
ijv_type prev = mm[0];
ap.push_back(0);
aj.push_back(prev.Col());
ax.push_back(prev.Val());
for (auto //typename std::vector<ijv_type>::const_iterator
it=(mm.begin()+1);it<mm.end();++it) {
ijv_type aij = (*it);
// row index
if (aij.Row() != prev.Row())
ap.push_back(aj.size());
if (aij == prev) {
aj.back() = aij.Col();
ax.back() += aij.Val();
} else {
aj.push_back(aij.Col());
ax.push_back(aij.Val());
}
prev = aij;
}
// add the last index to terminate the storage
ap.push_back(aj.size());
nnz = aj.size();
}
// create crs matrix view
A.create(m, n, nnz);
for (ordinal_type i=0;i<m;++i) {
A.RowPtrBegin(i) = ap.at(i);
A.RowPtrEnd(i) = ap.at(i+1);
}
for (ordinal_type k=0;k<nnz;++k) {
A.Col(k) = aj.at(k);
A.Value(k) = ax.at(k);
}
}
