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/fn_sylvester.hpp        | 137 +++++++++++++++++++++
 1 file changed, 137 insertions(+)
 create mode 100644 src/armadillo/include/armadillo_bits/fn_sylvester.hpp

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

diff --git a/src/armadillo/include/armadillo_bits/fn_sylvester.hpp b/src/armadillo/include/armadillo_bits/fn_sylvester.hpp
new file mode 100644
index 0000000..a5b8165
--- /dev/null
+++ b/src/armadillo/include/armadillo_bits/fn_sylvester.hpp
@@ -0,0 +1,137 @@
+// 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 fn_syl_lyap
+//! @{
+
+
+//! find the solution of the Sylvester equation AX + XB = C
+template<typename T1, typename T2, typename T3>
+inline
+bool
+syl
+  (
+        Mat <typename T1::elem_type>   & out,
+  const Base<typename T1::elem_type,T1>& in_A,
+  const Base<typename T1::elem_type,T2>& in_B,
+  const Base<typename T1::elem_type,T3>& in_C,
+  const typename arma_blas_type_only<typename T1::elem_type>::result* junk = nullptr
+  )
+  {
+  arma_extra_debug_sigprint();
+  arma_ignore(junk);
+  
+  typedef typename T1::elem_type eT;
+  
+  const unwrap_check<T1> tmp_A(in_A.get_ref(), out);
+  const unwrap_check<T2> tmp_B(in_B.get_ref(), out);
+  const unwrap_check<T3> tmp_C(in_C.get_ref(), out);
+  
+  const Mat<eT>& A = tmp_A.M;
+  const Mat<eT>& B = tmp_B.M;
+  const Mat<eT>& C = tmp_C.M;
+  
+  const bool status = auxlib::syl(out, A, B, C);
+  
+  if(status == false)
+    {
+    out.soft_reset();
+    arma_debug_warn_level(3, "syl(): solution not found");
+    }
+  
+  return status;
+  }
+
+
+
+template<typename T1, typename T2, typename T3>
+inline
+bool
+sylvester
+  (
+        Mat <typename T1::elem_type>   & out,
+  const Base<typename T1::elem_type,T1>& in_A,
+  const Base<typename T1::elem_type,T2>& in_B,
+  const Base<typename T1::elem_type,T3>& in_C,
+  const typename arma_blas_type_only<typename T1::elem_type>::result* junk = nullptr
+  )
+  {
+  arma_ignore(junk);
+  return syl(out, in_A, in_B, in_C);
+  }
+
+
+
+template<typename T1, typename T2, typename T3>
+arma_warn_unused
+inline
+Mat<typename T1::elem_type>
+syl
+  (
+  const Base<typename T1::elem_type,T1>& in_A,
+  const Base<typename T1::elem_type,T2>& in_B,
+  const Base<typename T1::elem_type,T3>& in_C,
+  const typename arma_blas_type_only<typename T1::elem_type>::result* junk = nullptr
+  )
+  {
+  arma_extra_debug_sigprint();
+  arma_ignore(junk);
+  
+  typedef typename T1::elem_type eT;
+  
+  const unwrap<T1> tmp_A( in_A.get_ref() );
+  const unwrap<T2> tmp_B( in_B.get_ref() );
+  const unwrap<T3> tmp_C( in_C.get_ref() );
+  
+  const Mat<eT>& A = tmp_A.M;
+  const Mat<eT>& B = tmp_B.M;
+  const Mat<eT>& C = tmp_C.M;
+  
+  Mat<eT> out;
+  
+  const bool status = auxlib::syl(out, A, B, C);
+  
+  if(status == false)
+    {
+    out.soft_reset();
+    arma_stop_runtime_error("syl(): solution not found");
+    }
+  
+  return out;
+  }
+
+
+
+template<typename T1, typename T2, typename T3>
+arma_warn_unused
+inline
+Mat<typename T1::elem_type>
+sylvester
+  (
+  const Base<typename T1::elem_type,T1>& in_A,
+  const Base<typename T1::elem_type,T2>& in_B,
+  const Base<typename T1::elem_type,T3>& in_C,
+  const typename arma_blas_type_only<typename T1::elem_type>::result* junk = nullptr
+  )
+  {
+  arma_ignore(junk);
+  return syl(in_A, in_B, in_C);
+  }
+
+
+//! @}
-- 
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