我有一个3D阵列double
s。我想编写简单的&通用函数来打印它的2D切片。如何将Boost.MultiArray的2D视图作为参数放入函数中?
代码:
#include <cstdio>
#include <boost/multi_array.hpp>
template<class M> // any model of MultiArray concept
void printFloatMatrix(typename M::template array_view<2u>::type matrix) {
using std::printf;
for(auto& row : matrix) {
for(auto& elem : row) {
printf("%5.3f ", elem);
}
printf("\n");
}
}
int main() {
typedef boost::multi_array<double,3> data_t;
data_t test_matrix{data_t::extent_gen()[10][10][2]};
// ...
using boost::indices;
using boost::multi_array_types::index_range;
printFloatMatrix(test_matrix[ indices[index_range()] [index_range()] [0] ]);
}
随着GCC这将产生错误消息:
test.cpp: In function ‘int main()’:
test.cpp:24:79: error: no matching function for call to ‘printFloatMatrix(boost::multi_array_ref<double, 3u>::array_view<2u>::type)’
test.cpp:24:79: note: candidate is:
test.cpp:5:6: note: template<class M> void printFloatMatrix(typename M::array_view<2u>::type)
为什么出错?
为什么M
被推断为boost::multi_array_ref<double, 3u>
?
如何编写可以工作的原型?
可能的重复[哪里,为什么我必须把“模板”和“typename”关键字?](http://stackoverflow.com/questions/610245/where-and-why-do-i-have -to-put-the-template-and-typename-keywords) – Xeo 2012-02-28 00:35:44