59 lines
1.8 KiB
C++
59 lines
1.8 KiB
C++
// SPDX-License-Identifier: Apache-2.0
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//
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// 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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namespace newarp
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{
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//! Calculate the eigenvalues and eigenvectors of a symmetric tridiagonal matrix.
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//! This class is a wrapper of the Lapack functions `_steqr`.
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template<typename eT>
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class TridiagEigen
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{
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private:
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blas_int n;
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Col<eT> main_diag; // Main diagonal elements of the matrix
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Col<eT> sub_diag; // Sub-diagonal elements of the matrix
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Mat<eT> evecs; // To store eigenvectors
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bool computed;
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public:
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//! Default constructor. Computation can
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//! be performed later by calling the compute() method.
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inline TridiagEigen();
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//! Constructor to create an object that calculates the eigenvalues
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//! and eigenvectors of a symmetric tridiagonal matrix `mat_obj`.
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inline TridiagEigen(const Mat<eT>& mat_obj);
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//! Compute the eigenvalue decomposition of a symmetric tridiagonal matrix.
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inline void compute(const Mat<eT>& mat_obj);
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//! Retrieve the eigenvalues.
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inline Col<eT> eigenvalues();
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//! Retrieve the eigenvectors.
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inline Mat<eT> eigenvectors();
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};
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} // namespace newarp
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