134 lines
3.4 KiB
C++
134 lines
3.4 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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//! \addtogroup glue_polyfit
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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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glue_polyfit::apply_noalias(Mat<eT>& out, const Col<eT>& X, const Col<eT>& Y, const uword N)
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{
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arma_extra_debug_sigprint();
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// create Vandermonde matrix
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Mat<eT> V(X.n_elem, N+1, arma_nozeros_indicator());
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V.tail_cols(1).ones();
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for(uword i=1; i <= N; ++i)
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{
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const uword j = N-i;
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Col<eT> V_col_j (V.colptr(j ), V.n_rows, false, false);
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Col<eT> V_col_jp1(V.colptr(j+1), V.n_rows, false, false);
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V_col_j = V_col_jp1 % X;
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}
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Mat<eT> Q;
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Mat<eT> R;
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const bool status1 = auxlib::qr_econ(Q, R, V);
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if(status1 == false) { return false; }
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const bool status2 = auxlib::solve_trimat_fast(out, R, (Q.t() * Y), uword(0));
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if(status2 == false) { return false; }
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return true;
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}
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template<typename T1, typename T2>
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inline
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bool
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glue_polyfit::apply_direct(Mat<typename T1::elem_type>& out, const Base<typename T1::elem_type,T1>& X_expr, const Base<typename T1::elem_type, T2>& Y_expr, const uword N)
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{
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arma_extra_debug_sigprint();
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typedef typename T1::elem_type eT;
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const quasi_unwrap<T1> UX(X_expr.get_ref());
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const quasi_unwrap<T2> UY(Y_expr.get_ref());
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const Mat<eT>& X = UX.M;
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const Mat<eT>& Y = UY.M;
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arma_debug_check
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(
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( ((X.is_vec() == false) && (X.is_empty() == false)) || ((Y.is_vec() == false) && (Y.is_empty() == false)) ),
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"polyfit(): given object must be a vector"
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);
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arma_debug_check( (X.n_elem != Y.n_elem), "polyfit(): given vectors must have the same number of elements" );
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if(X.n_elem == 0)
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{
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out.reset();
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return true;
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}
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arma_debug_check( (N >= X.n_elem), "polyfit(): N must be less than the number of elements in X" );
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const Col<eT> X_as_colvec( const_cast<eT*>(X.memptr()), X.n_elem, false, false);
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const Col<eT> Y_as_colvec( const_cast<eT*>(Y.memptr()), Y.n_elem, false, false);
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bool status = false;
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if(UX.is_alias(out) || UY.is_alias(out))
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{
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Mat<eT> tmp;
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status = glue_polyfit::apply_noalias(tmp, X_as_colvec, Y_as_colvec, N);
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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 = glue_polyfit::apply_noalias(out, X_as_colvec, Y_as_colvec, N);
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}
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return status;
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}
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template<typename T1, typename T2>
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inline
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void
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glue_polyfit::apply(Mat<typename T1::elem_type>& out, const Glue<T1,T2,glue_polyfit>& expr)
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{
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arma_extra_debug_sigprint();
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const bool status = glue_polyfit::apply_direct(out, expr.A, expr.B, expr.aux_uword);
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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("polyfit(): failed");
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}
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}
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//! @}
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