139 lines
3.2 KiB
C++
139 lines
3.2 KiB
C++
// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
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// Copyright 2008-2016 National ICT Australia (NICTA)
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// ------------------------------------------------------------------------
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//! \addtogroup op_roots
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//! @{
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template<typename T1>
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inline
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void
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op_roots::apply(Mat< std::complex<typename T1::pod_type> >& out, const mtOp<std::complex<typename T1::pod_type>, T1, op_roots>& expr)
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{
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arma_extra_debug_sigprint();
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const bool status = op_roots::apply_direct(out, expr.m);
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if(status == false)
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{
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out.soft_reset();
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arma_stop_runtime_error("roots(): eigen decomposition failed");
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}
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}
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template<typename T1>
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inline
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bool
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op_roots::apply_direct(Mat< std::complex<typename T1::pod_type> >& out, const Base<typename T1::elem_type, T1>& X)
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{
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arma_extra_debug_sigprint();
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typedef std::complex<typename T1::pod_type> out_eT;
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const quasi_unwrap<T1> U(X.get_ref());
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bool status = false;
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if(U.is_alias(out))
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{
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Mat<out_eT> tmp;
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status = op_roots::apply_noalias(tmp, U.M);
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out.steal_mem(tmp);
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}
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else
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{
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status = op_roots::apply_noalias(out, U.M);
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}
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return status;
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}
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template<typename eT>
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inline
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bool
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op_roots::apply_noalias(Mat< std::complex<typename get_pod_type<eT>::result> >& out, const Mat<eT>& X)
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{
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arma_extra_debug_sigprint();
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typedef typename get_pod_type<eT>::result T;
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typedef std::complex<typename get_pod_type<eT>::result> out_eT;
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arma_debug_check( (X.is_vec() == false), "roots(): given object must be a vector" );
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if(X.is_finite() == false) { return false; }
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// treat X as a column vector
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const Col<eT> Y( const_cast<eT*>(X.memptr()), X.n_elem, false, false);
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const T Y_max = (Y.is_empty() == false) ? T(max(abs(Y))) : T(0);
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if(Y_max == T(0)) { out.set_size(1,0); return true; }
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const uvec indices = find( Y / Y_max );
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const uword n_tail_zeros = (indices.n_elem > 0) ? uword( (Y.n_elem-1) - indices[indices.n_elem-1] ) : uword(0);
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const Col<eT> Z = Y.subvec( indices[0], indices[indices.n_elem-1] );
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if(Z.n_elem >= uword(2))
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{
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Mat<eT> tmp;
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if(Z.n_elem == uword(2))
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{
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tmp.set_size(1,1);
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tmp[0] = -Z[1] / Z[0];
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}
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else
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{
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tmp = diagmat(ones< Col<eT> >(Z.n_elem - 2), -1);
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tmp.row(0) = strans(-Z.subvec(1, Z.n_elem-1) / Z[0]);
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}
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Mat<out_eT> junk;
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const bool status = auxlib::eig_gen(out, junk, false, tmp);
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if(status == false) { return false; }
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if(n_tail_zeros > 0)
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{
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out.resize(out.n_rows + n_tail_zeros, 1);
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}
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}
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else
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{
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out.zeros(n_tail_zeros,1);
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}
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return true;
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}
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//! @}
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