Op_diagmat

Classes

class  op_diagmat

Functions

template<typename T1 >
static void op_diagmat::apply (Mat< typename T1::elem_type > &out, const Op< T1, op_diagmat > &X)

Function Documentation

template<typename T1 >
void op_diagmat::apply ( Mat< typename T1::elem_type > &  out,
const Op< T1, op_diagmat > &  X 
) [inline, static, inherited]

Definition at line 25 of file op_diagmat_meat.hpp.

References Mat< eT >::at(), Mat< eT >::is_square(), Mat< eT >::is_vec(), unwrap< T1 >::M, Op< T1, op_type >::m, podarray< eT >::memptr(), Mat< eT >::memptr(), Mat< eT >::n_elem, Mat< eT >::n_rows, Mat< eT >::set_size(), and Mat< eT >::zeros().

00026   {
00027   arma_extra_debug_sigprint();
00028   
00029   typedef typename T1::elem_type eT;
00030   
00031   const unwrap<T1>   tmp(X.m);
00032   const Mat<eT>& A = tmp.M;
00033   
00034   if(A.is_vec() == true)
00035     {
00036     // generate a diagonal matrix out of a vector
00037     
00038     const u32 N     = A.n_elem;
00039     const eT* A_mem = A.memptr();
00040     
00041     if(&out != &A)
00042       {
00043       // no aliasing
00044       out.zeros(N,N);
00045       
00046       for(u32 i=0; i<N; ++i)
00047         {
00048         out.at(i,i) = A_mem[i];
00049         }
00050       }
00051     else
00052       {
00053       // aliasing
00054       
00055       const podarray<eT> tmp(A_mem, N);
00056       
00057       const eT* tmp_mem = tmp.memptr();
00058       
00059       out.zeros(N,N);
00060       
00061       for(u32 i=0; i<N; ++i)
00062         {
00063         out.at(i,i) = tmp_mem[i];
00064         }
00065       }
00066     }
00067   else
00068     {
00069     // generate a diagonal matrix out of a matrix
00070     
00071     arma_debug_check( (A.is_square() == false), "diagmat(): given matrix is not square" );
00072     
00073     const u32 N = A.n_rows;
00074     
00075     out.set_size(N,N);
00076     
00077     for(u32 col=0; col<N; ++col)
00078       {
00079       for(u32 row=0;     row<col; ++row) { out.at(row,col) = eT(0); }
00080       
00081       out.at(col,col) = A.at(col,col);
00082       
00083       for(u32 row=col+1; row<N;   ++row) { out.at(row,col) = eT(0); }
00084       }
00085     }
00086   }