sn_jacob.h

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#ifndef __sn_jacob_h__
#define __sn_jacob_h__
 
namespace Chroma {
 
//! Single-node Jacobi rotation
/*!
 * \ingroup eig
 *
 * This subroutine contains a "single node" Jacobi routine
 * to be used with the Ritz functional eigenvialue/std::vector finder.
 *
 *
 *  \param psi          Eigenvectors                    (Modify)
 *  \param N_eig        Eigenvalue number               (Read)
 *  \param lambda       Diagonals / Eigenvalues         (Modify)
 *  \param off_diag     Upper triang off-diag matrix elems      (Modify)
 *  \param tolererance  Tolerance for off-diag elems    (Read)
 *  \param N_max        Maximal number of Jacobi iters  (Read)
 *  \param sub          Subset to use                   (Read) 
 *
 *  \return             Number of Jacobi iters          (Write) 
 */
int SN_Jacob(multi1d<LatticeFermion>& psi, 
             const int N_eig, 
             multi1d<Real>& lambda, 
             multi1d<Complex>& off_diag, 
             Real tolerance, 
             int N_max,
             const Subset& sub);
 
}  // end namespace Chroma
 
#endif