[英]Assign a std::vector to a std::valarray
I have a vector<vector<double>
, so a table (matrix) of values. 我有一个vector<vector<double>
,所以有一个值的表(矩阵)。 Columns contains position and velocity of a planet, so rows stores data of the same planet. 列包含行星的位置和速度,因此行存储同一行星的数据。 I want to transform a row in a valarray
because I need math operations. 我想在valarray
变换一行,因为我需要数学运算。 Then I want to store the valarrays (the planets) in a vector. 然后我想将valarrays(行星)存储在矢量中。 I tried like this: 我试过这样的:
vector<vector<double>> corps_tmp=configFile.get_corps(); // The function returns a vector<vector<double>>
valarray<double> corpX;
for (int i(0); i < corps_tmp.size(); i++) {
corpX = corps_tmp[i]; // I want to save the first row of the vector<vector<double>> on the valarray
corps.push_back(corpX); // I want to ''add'' the valarray to a vector.
corpX = 0;
}
This code doesn't works and I obtain an error around the assignment of a vector to a valarray (apparently not permitted). 这段代码不起作用,我在向valarray指定向量时显然是错误的(显然是不允许的)。
Is there any way to achieve in a simple way what I tried to do? 有没有办法以一种简单的方式实现我的目标?
To create a valarray from a vector: 要从矢量创建一个valarray:
std:valarray<double> corpX(corps_tmp[i].data(), corps_tmp[i].size());
To write the data back into a vector: 要将数据写回向量:
corps_tmp[i].assign(std::begin(corpX), std::end(corpX));
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