comparison armadillo-2.4.4/include/armadillo_bits/op_diagmat_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_diagmat
+//! @{
+
+
+
+template<typename T1>
+inline
+void
+op_diagmat::apply(Mat<typename T1::elem_type>& out, const Op<T1, op_diagmat>& X)
+  {
+  arma_extra_debug_sigprint();
+  
+  typedef typename T1::elem_type eT;
+  
+  const unwrap<T1>   tmp(X.m);
+  const Mat<eT>& A = tmp.M;
+  
+  if(A.is_vec() == true)
+    {
+    // generate a diagonal matrix out of a vector
+    
+    const uword N     = A.n_elem;
+    const eT* A_mem = A.memptr();
+    
+    if(&out != &A)
+      {
+      // no aliasing
+      out.zeros(N,N);
+      
+      for(uword i=0; i<N; ++i)
+        {
+        out.at(i,i) = A_mem[i];
+        }
+      }
+    else
+      {
+      // aliasing
+      
+      const podarray<eT> tmp(A_mem, N);
+      
+      const eT* tmp_mem = tmp.memptr();
+      
+      out.zeros(N,N);
+      
+      for(uword i=0; i<N; ++i)
+        {
+        out.at(i,i) = tmp_mem[i];
+        }
+      }
+    }
+  else
+    {
+    // generate a diagonal matrix out of a matrix
+    
+    arma_debug_check( (A.is_square() == false), "diagmat(): given matrix is not square" );
+    
+    const uword N = A.n_rows;
+    
+    if(&out != &A)
+      {
+      // no aliasing
+      
+      out.zeros(N,N);
+      
+      for(uword i=0; i<N; ++i)
+        {
+        out.at(i,i) = A.at(i,i);
+        }
+      }
+    else
+      {
+      // aliasing
+      
+      for(uword i=0; i<N; ++i)
+        {
+        eT* colptr = out.colptr(i);
+        
+        // clear above the diagonal
+        arrayops::inplace_set(colptr, eT(0), i);
+        
+        // clear below the diagonal
+        arrayops::inplace_set(colptr+(i+1), eT(0), N-1-i);
+        }
+      }
+    }
+  }
+
+
+
+//! @}