C++特征库中的argmax()方法

#include <Eigen/Dense>
int main(){
   Eigen::Tensor<double, 3> table(4,200,200);
   table.setRandom();
   // How can I do this task for axis = 2, i.e depth of a tensor?
   // int max_axis = table.argmax(ax=2); 
   return 0;
}

arma::Cube<double> A(200, 200, 4, arma::fill::randu);
uword i = A(arma::span(1),  arma::span(1), arma::span::all).index_max();

  std::array<int, 1> reduce_dims{2};                                            
  Eigen::Tensor<Eigen::Tuple<Eigen::Index, double>, 2> reduced =                 
      table.index_tuples().reduce(reduce_dims,                                  
                                  Eigen::internal::ArgMaxTupleReducer<          
                                      Eigen::Tuple<Eigen::Index, double> >());

for (int c = 0; c < reduced.dimension(1); ++c) {                                 
  for (int r = 0; r < reduced.dimension(0); ++r) {                            
    Eigen::Index argmax_channel_index =                                       
        reduced(r, c).first / (table.dimension(0) * table.dimension(1));      
    std::cout << "argmax channel: " << argmax_channel_index << " "            
              << "max: " << reduced(r, c).second << std::endl;                
}

#include <Eigen/Dense>
#include <unsupported/Eigen/CXX11/Tensor>
#include <iostream>
#define STR_(x)  #x
#define STR(x)  STR_(x)
#define PRINT(x)  std::cout << STR(x) << ":\n" << (x) << std::endl
int main()
    using namespace Eigen;
    using T = int;
    using S = Sizes<2, 3>;
    S const sizes{};
    T constexpr data[S::total_size]{
        8, 4,
        1, 6,
        9, 2,
    Map<MatrixX<T> const> const matrix(data, sizes[0], sizes[1]);
    PRINT(matrix);
    RowVector2<Index> argmax{};
    matrix.maxCoeff(&argmax.x(), &argmax.y());
    PRINT(argmax);
    VectorX<Index> argmax0{matrix.cols()};
    for (Index col = 0; col < matrix.cols(); ++col)
        matrix.col(col).maxCoeff(&argmax0[col]);
    PRINT(argmax0);
    VectorX<Index> argmax1{matrix.rows()};
    for (Index row = 0; row < matrix.rows(); ++row)
        matrix.row(row).maxCoeff(&argmax1[row]);
    PRINT(argmax1);
    TensorMap<Tensor<T const, S::count>> const tensor(data, sizes);
    PRINT(tensor);
    PRINT(tensor.argmax());
    PRINT(tensor.argmax(0));
    PRINT(tensor.argmax(1));
    // Note that tensor.argmax() is the index for a 1D view of the data:
    Index const matrix_index = sizes.IndexOfColMajor(std::array{argmax.x(), argmax.y()});
    Index const tensor_index = Tensor<Index, 0>{tensor.argmax()}();
    PRINT(matrix_index == tensor_index);
}

matrix:
8 1 9
4 6 2
argmax:
argmax0:
argmax1:
tensor:
8 1 9
4 6 2
tensor.argmax():
tensor.argmax(0):

C++特征库中的argmax()方法

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