max@0: // Copyright (C) 2010-2011 NICTA (www.nicta.com.au)
max@0: // Copyright (C) 2010-2011 Conrad Sanderson
max@0: // 
max@0: // This file is part of the Armadillo C++ library.
max@0: // It is provided without any warranty of fitness
max@0: // for any purpose. You can redistribute this file
max@0: // and/or modify it under the terms of the GNU
max@0: // Lesser General Public License (LGPL) as published
max@0: // by the Free Software Foundation, either version 3
max@0: // of the License or (at your option) any later version.
max@0: // (see http://www.opensource.org/licenses for more info)
max@0: 
max@0: 
max@0: //! \addtogroup fn_log_det
max@0: //! @{
max@0: 
max@0: 
max@0: 
max@0: //! log determinant of mat
max@0: template<typename T1>
max@0: inline
max@0: bool
max@0: log_det
max@0:   (
max@0:         typename T1::elem_type&          out_val,
max@0:         typename T1::pod_type&           out_sign,
max@0:   const Base<typename T1::elem_type,T1>& X,
max@0:   const typename arma_blas_type_only<typename T1::elem_type>::result* junk = 0
max@0:   )
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   arma_ignore(junk);
max@0:   
max@0:   return auxlib::log_det(out_val, out_sign, X);
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: template<typename T1>
max@0: inline
max@0: void
max@0: log_det
max@0:   (
max@0:         typename T1::elem_type& out_val,
max@0:         typename T1::pod_type&  out_sign,
max@0:   const Op<T1,op_diagmat>&      X,
max@0:   const typename arma_blas_type_only<typename T1::elem_type>::result* junk = 0
max@0:   )
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   arma_ignore(junk);
max@0:   
max@0:   typedef typename T1::elem_type eT;
max@0:   typedef typename T1::pod_type   T;
max@0:   
max@0:   const diagmat_proxy<T1> A(X.m);
max@0:   
max@0:   const uword N = A.n_elem;
max@0:   
max@0:   if(N == 0)
max@0:     {
max@0:     out_val  = eT(0);
max@0:     out_sign =  T(1);
max@0:     
max@0:     return;
max@0:     }
max@0:   
max@0:   const eT x = A[0];
max@0:   
max@0:   T  sign = (is_complex<eT>::value == false) ? ( (access::tmp_real(x) < T(0)) ? -1 : +1 ) : +1;
max@0:   eT val  = (is_complex<eT>::value == false) ? std::log( (access::tmp_real(x) < T(0)) ? x*T(-1) : x ) : std::log(x);
max@0:   
max@0:   for(uword i=1; i<N; ++i)
max@0:     {
max@0:     const eT x = A[i];
max@0:     
max@0:     sign *= (is_complex<eT>::value == false) ? ( (access::tmp_real(x) < T(0)) ? -1 : +1 ) : +1;
max@0:     val  += (is_complex<eT>::value == false) ? std::log( (access::tmp_real(x) < T(0)) ? x*T(-1) : x ) : std::log(x);
max@0:     }
max@0:   
max@0:   out_val  = val;
max@0:   out_sign = sign;
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! @}