Question

似乎Eigen不检查动态矩阵的维数。例如，如果我执行以下代码：

auto EA = Eigen::MatrixXf(3, 2);
auto EB = Eigen::MatrixXf(3, 2);
for (auto i = 0; i < 3; ++i)
{
  for (auto j = 0; j < 2; ++j)
  {
    EA(i,j) = i + j + 1;
    EB(i,j) = i + j + 1;
  }
}
auto EC = EA*EB;
std::cout << "EA: " << std::endl << EA << std::endl;
std::cout << "EB: " << std::endl << EB << std::endl;
std::cout << "EC: " << std::endl << EC << std::endl;

它输出：

如何强制Eigen在运行时检查矩阵尺寸？这对于初学者和调试真的很有用。

Answer 1

仅当未定义NDEBUG宏时才进行尺寸检查。这通常意味着调试版本。

不带NDEBUG的示例，其中检查成功中止了程序：

g++ test.cpp -o test -I /usr/include/eigen3 && ./test
test: /usr/include/eigen3/Eigen/src/Core/ProductBase.h:102: Eigen::ProductBase<Derived, Lhs, Rhs>::ProductBase(const Lhs&, const Rhs&) [with Derived = Eigen::GeneralProduct<Eigen::Matrix<float, -1, -1>, Eigen::Matrix<float, -1, -1>, 5>; Lhs = Eigen::Matrix<float, -1, -1>; Rhs = Eigen::Matrix<float, -1, -1>]: Assertion `a_lhs.cols() == a_rhs.rows() && "invalid matrix product" && "if you wanted a coeff-wise or a dot product use the respective explicit functions"' failed.
Aborted (core dumped)

使用NDEBUG：

g++ test.cpp -o test -I /usr/include/eigen3 -DNDEBUG && ./test
EA: 
1 2
2 3
3 4
EB: 
1 2
2 3
3 4
EC: 
 5  8
 8 13
11 18

强制Eigen在运行时检查矩阵尺寸

1 个答案: