void
convert_matrix(const arma::Mat<Tfrom>& densemat,
csc_matrix<Tto, Idxto>& cscmat) {
Idxto m = densemat.num_rows();
Idxto n = densemat.num_cols();
arma::Col<Idxto> new_col_offsets(n + 1, 0);
arma::Col<Idxto> new_row_indices;
arma::Col<Tto> new_values;
// Compute column sizes, and fill vectors of row indices and values.
for (Idxto j(0); j < n; ++j) {
for (Idxto i(0); i < m; ++i) {
if (densemat(i,j) != 0) {
++new_col_offsets[j];
new_row_indices.push_back(i);
new_values.push_back(densemat(i,j));
}
}
}
// Compute offsets.
for (Idxto i(0); i < n; ++i)
new_col_offsets[i+1] += new_col_offsets[i];
for (Idxto i(n); i > 0; --i)
new_col_offsets[i] = new_col_offsets[i-1];
new_col_offsets[0] = 0;
// Copy data over
cscmat.reset_nocopy(m, n, new_col_offsets, new_row_indices, new_values);
}
explicit csc_matrix(const arma::Mat<OtherT>& other)
: base(other.num_rows(), other.num_cols()) {
convert_matrix(other, *this);
}