void
fgRealSymmEigs(
const FgMatrixV<T> &rsm,
FgMatrixV<T> &val, // RETURNED: Col vector of eigenvalues, smallest to largest
FgMatrixV<T> &vec) // RETURNED: Col vectors are respective eigenvectors
{
// JAMA enters an infinite loop with NaNs:
for (size_t ii=0; ii<rsm.m_data.size(); ++ii)
FGASSERT(boost::math::isfinite(rsm.m_data[ii]));
uint dim = rsm.numRows();
FGASSERT(rsm.numCols() == dim);
// We use a const cast since we know 'solver' will not modify the elements, even though
// the Array2D object holds a non-const pointer to our data.
JAMA::Eigenvalue<T>
solver(TNT::Array2D<T>(rsm.numRows(),rsm.numCols(),const_cast<T*>(rsm.dataPtr())));
TNT::Array2D<T> vecs;
TNT::Array1D<T> vals;
solver.getV(vecs);
solver.getRealEigenvalues(vals);
val.resize(dim,1);
vec.resize(dim,dim);
int idim = static_cast<int>(dim);
for (int row=0; row<idim; row++) {
val[row] = vals[row];
for (uint col=0; col<dim; col++)
vec.elem(row,col) = vecs[row][col];
}
}
