comparison armadillo-2.4.4/include/armadillo_bits/op_inv_meat.hpp @ 0:8b6102e2a9b0

Armadillo Library

+// Copyright (C) 2008-2011 NICTA (www.nicta.com.au)
+// Copyright (C) 2008-2011 Conrad Sanderson
+// 
+// This file is part of the Armadillo C++ library.
+// It is provided without any warranty of fitness
+// for any purpose. You can redistribute this file
+// and/or modify it under the terms of the GNU
+// Lesser General Public License (LGPL) as published
+// by the Free Software Foundation, either version 3
+// of the License or (at your option) any later version.
+// (see http://www.opensource.org/licenses for more info)
+
+
+//! \addtogroup op_inv
+//! @{
+
+
+//! immediate inverse of a matrix, storing the result in a dense matrix
+template<typename eT>
+inline
+void
+op_inv::apply(Mat<eT>& out, const Mat<eT>& A, const bool slow)
+  {
+  arma_extra_debug_sigprint();
+  
+  // no need to check for aliasing, due to:
+  // - auxlib::inv() copies A to out before inversion
+  // - for 2x2 and 3x3 matrices the code is alias safe
+  
+  bool status = auxlib::inv(out, A, slow);
+  
+  if(status == false)
+    {
+    out.reset();
+    arma_bad("inv(): matrix appears to be singular");
+    }
+  }
+
+
+
+//! immediate inverse of T1, storing the result in a dense matrix
+template<typename T1>
+inline
+void
+op_inv::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv>& X)
+  {
+  arma_extra_debug_sigprint();
+  
+  typedef typename T1::elem_type eT;
+  
+  const strip_diagmat<T1> strip(X.m);
+  
+  if(strip.do_diagmat == true)
+    {
+    op_inv::apply_diag(out, strip.M);
+    }
+  else
+    {
+    const uword mode = X.aux_uword_a;
+    
+    const bool status = (mode == 0) ? auxlib::inv(out, X.m) : auxlib::inv(out, X.m, true);
+    
+    if(status == false)
+      {
+      out.reset();
+      arma_bad("inv(): matrix appears to be singular");
+      }
+    }
+  }
+
+
+
+template<typename T1>
+inline
+void
+op_inv::apply_diag(Mat<typename T1::elem_type>& out, const Base<typename T1::elem_type, T1>& X)
+  {
+  arma_extra_debug_sigprint();
+  
+  typedef typename T1::elem_type eT;
+  
+  const diagmat_proxy_check<T1> A(X.get_ref(), out);
+  
+  const uword N = A.n_elem;
+  
+  out.set_size(N,N);
+  
+  for(uword col=0; col<N; ++col)
+    {
+    for(uword row=0; row<col; ++row)   { out.at(row,col) = eT(0); }
+    
+    out.at(col,col) = eT(1) / A[col];
+    
+    for(uword row=col+1; row<N; ++row) { out.at(row,col) = eT(0); }
+    }
+  
+  }
+
+
+
+//! inverse of T1 (triangular matrices)
+template<typename T1>
+inline
+void
+op_inv_tr::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv_tr>& X)
+  {
+  arma_extra_debug_sigprint();
+  
+  const bool status = auxlib::inv_tr(out, X.m, X.aux_uword_a);
+  
+  if(status == false)
+    {
+    out.reset();
+    arma_bad("inv(): matrix appears to be singular");
+    }
+  }
+
+
+
+//! inverse of T1 (symmetric positive definite matrices)
+template<typename T1>
+inline
+void
+op_inv_sympd::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv_sympd>& X)
+  {
+  arma_extra_debug_sigprint();
+  
+  const bool status = auxlib::inv_sympd(out, X.m, X.aux_uword_a);
+  
+  if(status == false)
+    {
+    out.reset();
+    arma_bad("inv(): matrix appears to be singular");
+    }
+  }
+
+
+
+//! @}