问题描述
下面的代码,
#include <iostream>
#include "xtensor/xadapt.hpp"
#include "xtensor/xarray.hpp"
#include "xtensor/xindex_view.hpp"
#include "xtensor/xio.hpp"
#include "xtensor/xmasked_view.hpp"
#include "xtensor/xview.hpp"
using namespace std;
int main() {
xt::xarray<float> a = {{1,2,3},{4,6},{9,2}};
cout << a << endl;
xt::filter(a,a == 2) = 10;
cout << a << endl;
}
使用以下内容编译失败:error: no match for ‘operator==’ (operand types are ‘xt::xarray<float>’
... and ‘int’)
但是,其他比较运算符按预期工作(>、=、
解决方法
您可以使用 xt::equal(a,b)
代替 a == b
。即
xt::filter(a,xt::equal(a,2)) = 10;
做你想做的事。
,xtensor 提供了 &&
和 ||
等逻辑运算符。将这些与允许的比较相结合会产生与“==”或“!=”预期相同的输出。
特别是 a >= 2 && a <= 2
a == 2
和 a > 2 || a < 2
a != 2
所以我的最终程序是
#include <iostream>
#include "xtensor/xadapt.hpp"
#include "xtensor/xarray.hpp"
#include "xtensor/xindex_view.hpp"
#include "xtensor/xio.hpp"
#include "xtensor/xmasked_view.hpp"
#include "xtensor/xview.hpp"
using namespace std;
int main() {
xt::xarray<float> a = {{1,2,3},{4,6},{9,2}};
cout << a << endl;
xt::filter(a,a >= 2 && a <= 2) = 10;
cout << a << endl;
}
它的输出是
{{ 1.,2.,3.},{ 4.,6.},{ 9.,0.,2.}}
{{ 1.,10.,{ 4.,{ 9.,10.}}