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authorNao Pross <np@0hm.ch>2024-02-12 14:52:43 +0100
committerNao Pross <np@0hm.ch>2024-02-12 14:52:43 +0100
commiteda5bc26f44ee9a6f83dcf8c91f17296d7fc509d (patch)
treebc2efa38ff4e350f9a111ac87065cd7ae9a911c7 /src/armadillo/include/armadillo_bits/op_roots_meat.hpp
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Move into version control
Diffstat (limited to 'src/armadillo/include/armadillo_bits/op_roots_meat.hpp')
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+// SPDX-License-Identifier: Apache-2.0
+//
+// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
+// Copyright 2008-2016 National ICT Australia (NICTA)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// ------------------------------------------------------------------------
+
+
+//! \addtogroup op_roots
+//! @{
+
+
+
+template<typename T1>
+inline
+void
+op_roots::apply(Mat< std::complex<typename T1::pod_type> >& out, const mtOp<std::complex<typename T1::pod_type>, T1, op_roots>& expr)
+ {
+ arma_extra_debug_sigprint();
+
+ const bool status = op_roots::apply_direct(out, expr.m);
+
+ if(status == false)
+ {
+ out.soft_reset();
+ arma_stop_runtime_error("roots(): eigen decomposition failed");
+ }
+ }
+
+
+
+template<typename T1>
+inline
+bool
+op_roots::apply_direct(Mat< std::complex<typename T1::pod_type> >& out, const Base<typename T1::elem_type, T1>& X)
+ {
+ arma_extra_debug_sigprint();
+
+ typedef std::complex<typename T1::pod_type> out_eT;
+
+ const quasi_unwrap<T1> U(X.get_ref());
+
+ bool status = false;
+
+ if(U.is_alias(out))
+ {
+ Mat<out_eT> tmp;
+
+ status = op_roots::apply_noalias(tmp, U.M);
+
+ out.steal_mem(tmp);
+ }
+ else
+ {
+ status = op_roots::apply_noalias(out, U.M);
+ }
+
+ return status;
+ }
+
+
+
+template<typename eT>
+inline
+bool
+op_roots::apply_noalias(Mat< std::complex<typename get_pod_type<eT>::result> >& out, const Mat<eT>& X)
+ {
+ arma_extra_debug_sigprint();
+
+ typedef typename get_pod_type<eT>::result T;
+
+ typedef std::complex<typename get_pod_type<eT>::result> out_eT;
+
+ arma_debug_check( (X.is_vec() == false), "roots(): given object must be a vector" );
+
+ if(X.internal_has_nonfinite()) { return false; }
+
+ // treat X as a column vector
+
+ const Col<eT> Y( const_cast<eT*>(X.memptr()), X.n_elem, false, false);
+
+ const T Y_max = (Y.is_empty() == false) ? T(max(abs(Y))) : T(0);
+
+ if(Y_max == T(0)) { out.set_size(1,0); return true; }
+
+ const uvec indices = find( Y / Y_max );
+
+ const uword n_tail_zeros = (indices.n_elem > 0) ? uword( (Y.n_elem-1) - indices[indices.n_elem-1] ) : uword(0);
+
+ const Col<eT> Z = Y.subvec( indices[0], indices[indices.n_elem-1] );
+
+ if(Z.n_elem >= uword(2))
+ {
+ Mat<eT> tmp;
+
+ if(Z.n_elem == uword(2))
+ {
+ tmp.set_size(1,1);
+
+ tmp[0] = -Z[1] / Z[0];
+ }
+ else
+ {
+ tmp = diagmat(ones< Col<eT> >(Z.n_elem - 2), -1);
+
+ tmp.row(0) = strans(-Z.subvec(1, Z.n_elem-1) / Z[0]);
+ }
+
+ Mat<out_eT> junk;
+
+ const bool status = auxlib::eig_gen(out, junk, false, tmp);
+
+ if(status == false) { return false; }
+
+ if(n_tail_zeros > 0)
+ {
+ out.resize(out.n_rows + n_tail_zeros, 1);
+ }
+ }
+ else
+ {
+ out.zeros(n_tail_zeros,1);
+ }
+
+ return true;
+ }
+
+
+
+//! @}