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diff --git a/src/armadillo/include/armadillo_bits/newarp_DoubleShiftQR_bones.hpp b/src/armadillo/include/armadillo_bits/newarp_DoubleShiftQR_bones.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.
+// ------------------------------------------------------------------------
+
+
+namespace newarp
+{
+
+
+template<typename eT>
+class DoubleShiftQR
+  {
+  private:
+
+  uword               n;        // Dimension of the matrix
+  Mat<eT>             mat_H;    // A copy of the matrix to be factorised
+  eT                  shift_s;  // Shift constant
+  eT                  shift_t;  // Shift constant
+  Mat<eT>             ref_u;    // Householder reflectors
+  Col<unsigned short> ref_nr;   // How many rows does each reflector affects
+                                // 3 - A general reflector
+                                // 2 - A Givens rotation
+                                // 1 - An identity transformation
+  const eT            prec;     // Approximately zero
+  const eT            eps_rel;
+  const eT            eps_abs;
+  bool                computed; // Whether matrix has been factorised
+
+  inline      void compute_reflector(const eT& x1, const eT& x2, const eT& x3, uword ind);
+  arma_inline void compute_reflector(const eT* x, uword ind);
+
+  // Update the block X = H(il:iu, il:iu)
+  inline void update_block(uword il, uword iu);
+
+  // P = I - 2 * u * u' = P'
+  // PX = X - 2 * u * (u'X)
+  inline void apply_PX(Mat<eT>& X, uword oi, uword oj, uword nrow, uword ncol, uword u_ind);
+
+  // x is a pointer to a vector
+  // Px = x - 2 * dot(x, u) * u
+  inline void apply_PX(eT* x, uword u_ind);
+
+  // XP = X - 2 * (X * u) * u'
+  inline void apply_XP(Mat<eT>& X, uword oi, uword oj, uword nrow, uword ncol, uword u_ind);
+
+
+  public:
+
+  inline DoubleShiftQR(uword size);
+
+  inline DoubleShiftQR(const Mat<eT>& mat_obj, eT s, eT t);
+
+  inline void compute(const Mat<eT>& mat_obj, eT s, eT t);
+
+  inline Mat<eT> matrix_QtHQ();
+
+  inline void apply_QtY(Col<eT>& y);
+
+  inline void apply_YQ(Mat<eT>& Y);
+  };
+
+
+}  // namespace newarp