From eda5bc26f44ee9a6f83dcf8c91f17296d7fc509d Mon Sep 17 00:00:00 2001
From: Nao Pross <np@0hm.ch>
Date: Mon, 12 Feb 2024 14:52:43 +0100
Subject: Move into version control

---
 .../include/armadillo_bits/glue_intersect_meat.hpp | 148 +++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 src/armadillo/include/armadillo_bits/glue_intersect_meat.hpp

(limited to 'src/armadillo/include/armadillo_bits/glue_intersect_meat.hpp')

diff --git a/src/armadillo/include/armadillo_bits/glue_intersect_meat.hpp b/src/armadillo/include/armadillo_bits/glue_intersect_meat.hpp
new file mode 100644
index 0000000..21a2b6d
--- /dev/null
+++ b/src/armadillo/include/armadillo_bits/glue_intersect_meat.hpp
@@ -0,0 +1,148 @@
+// 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 glue_intersect
+//! @{
+
+
+
+template<typename T1, typename T2>
+inline
+void
+glue_intersect::apply(Mat<typename T1::elem_type>& out, const Glue<T1,T2,glue_intersect>& X)
+  {
+  arma_extra_debug_sigprint();
+  
+  uvec iA;
+  uvec iB;
+  
+  glue_intersect::apply(out, iA, iB, X.A, X.B, false);
+  }
+
+
+
+template<typename T1, typename T2>
+inline
+void
+glue_intersect::apply(Mat<typename T1::elem_type>& out, uvec& iA, uvec& iB, const Base<typename T1::elem_type,T1>& A_expr, const Base<typename T1::elem_type,T2>& B_expr, const bool calc_indx)
+  {
+  arma_extra_debug_sigprint();
+  
+  typedef typename T1::elem_type eT;
+  
+  const quasi_unwrap<T1> UA(A_expr.get_ref());
+  const quasi_unwrap<T2> UB(B_expr.get_ref());
+  
+  if(UA.M.is_empty() || UB.M.is_empty())
+    {
+    out.reset();
+    iA.reset();
+    iB.reset();
+    return;
+    }
+  
+  uvec A_uniq_indx;
+  uvec B_uniq_indx; 
+  
+  Mat<eT> A_uniq;
+  Mat<eT> B_uniq; 
+  
+  if(calc_indx)
+    {
+    A_uniq_indx = find_unique(UA.M);
+    B_uniq_indx = find_unique(UB.M);
+    
+    A_uniq = UA.M.elem(A_uniq_indx);
+    B_uniq = UB.M.elem(B_uniq_indx);
+    }
+  else
+    {
+    A_uniq = unique(UA.M);
+    B_uniq = unique(UB.M);
+    }
+  
+  const uword C_n_elem = A_uniq.n_elem + B_uniq.n_elem;
+  
+  Col<eT> C(C_n_elem, arma_nozeros_indicator());
+  
+  arrayops::copy(C.memptr(),                 A_uniq.memptr(), A_uniq.n_elem);
+  arrayops::copy(C.memptr() + A_uniq.n_elem, B_uniq.memptr(), B_uniq.n_elem);
+  
+  uvec    C_sorted_indx;
+  Col<eT> C_sorted;
+  
+  if(calc_indx)
+    {
+    C_sorted_indx = stable_sort_index(C);
+    C_sorted      = C.elem(C_sorted_indx);
+    }
+  else
+    {
+    C_sorted = sort(C);
+    }
+  
+  const eT* C_sorted_mem = C_sorted.memptr();
+  
+  uvec   jj(C_n_elem, arma_nozeros_indicator());  // worst case length
+  
+  uword* jj_mem   = jj.memptr();  
+  uword  jj_count = 0;
+  
+  for(uword i=0; i < (C_n_elem-1); ++i)
+    {
+    if( C_sorted_mem[i] == C_sorted_mem[i+1] )
+      {
+      jj_mem[jj_count] = i;
+      ++jj_count;
+      }
+    }
+  
+  if(jj_count == 0)
+    {
+    out.reset();
+    iA.reset();
+    iB.reset();
+    return;
+    }
+  
+  const uvec ii(jj.memptr(), jj_count, false);
+  
+  if(UA.M.is_rowvec() && UB.M.is_rowvec())
+    {
+    out.set_size(1, ii.n_elem);
+    
+    Mat<eT> out_alias(out.memptr(), ii.n_elem, 1, false, true);
+    
+    // NOTE: this relies on .elem() not changing the size of the output and not reallocating memory for the output
+    out_alias = C_sorted.elem(ii);
+    }
+  else
+    {
+    out = C_sorted.elem(ii);
+    }
+  
+  if(calc_indx)
+    {
+    iA = A_uniq_indx.elem(C_sorted_indx.elem(ii  )                );
+    iB = B_uniq_indx.elem(C_sorted_indx.elem(ii+1) - A_uniq.n_elem);
+    }
+  }
+
+
+
+//! @}
-- 
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