Classes | |
class | op_sum |
Class for finding sums of values in a matrix (e.g. along rows or columns). More... | |
Functions | |
template<typename T1 > | |
static void | op_sum::apply (Mat< typename T1::elem_type > &out, const Op< T1, op_sum > &in) |
Immediate sum of elements of a matrix along a specified dimension (either rows or columns). The result is stored in a dense matrix that has either one column or one row. See the sum() function for more details. |
void op_sum::apply | ( | Mat< typename T1::elem_type > & | out, | |
const Op< T1, op_sum > & | in | |||
) | [inline, static, inherited] |
Immediate sum of elements of a matrix along a specified dimension (either rows or columns). The result is stored in a dense matrix that has either one column or one row. See the sum() function for more details.
Definition at line 26 of file op_sum_meat.hpp.
References Mat< eT >::at(), Op< T1, op_type >::aux_u32_a, Mat< eT >::colptr(), Op< T1, op_type >::m, Mat< eT >::n_cols, Mat< eT >::n_elem, Mat< eT >::n_rows, and Mat< eT >::set_size().
00027 { 00028 arma_extra_debug_sigprint(); 00029 00030 const u32 dim = in.aux_u32_a; 00031 arma_debug_check( (dim > 1), "sum(): incorrect usage. dim must be 0 or 1"); 00032 00033 typedef typename T1::elem_type eT; 00034 00035 const unwrap_check<T1> tmp(in.m, out); 00036 const Mat<eT>& X = tmp.M; 00037 00038 arma_debug_check( (X.n_elem < 1), "sum(): given object has no elements"); 00039 00040 00041 if(dim == 0) // traverse across rows (i.e. find the sum in each column) 00042 { 00043 out.set_size(1, X.n_cols); 00044 00045 for(u32 col=0; col < X.n_cols; ++col) 00046 { 00047 const eT* X_colptr = X.colptr(col); 00048 00049 eT val = eT(0); 00050 00051 for(u32 row=0; row < X.n_rows; ++row) 00052 { 00053 val += X_colptr[row]; 00054 } 00055 00056 out.at(0,col) = val; 00057 } 00058 } 00059 else // traverse across columns (i.e. find the sum in each rows) 00060 { 00061 out.set_size(X.n_rows, 1); 00062 00063 for(u32 row=0; row < X.n_rows; ++row) 00064 { 00065 eT val = eT(0); 00066 00067 for(u32 col=0; col<X.n_cols; ++col) 00068 { 00069 val += X.at(row,col); 00070 } 00071 00072 out.at(row,0) = val; 00073 } 00074 00075 } 00076 00077 }