比较Google Test或Google Mock中的本征矩阵 [英] Compare Eigen matrices in Google Test or Google Mock

问题描述

我想知道是否有一种很好的方法来测试两个本征矩阵使用 Google测试或 Google Mock 。

I was wondering if there is a good way to test two Eigen matrices for approximate equality using Google Test, or Google Mock.

将以下测试用例作为一个简化的示例：我将两个复值矩阵 A 和 B 相乘，并期望得到一定的结果 C_expect 。我使用Eigen计算数值结果 C_actual = A * B 。现在，我想比较 C_expect 和 C_actual 。现在，相应的代码如下：

Take the following test-case as a simplified example: I am multiplying two complex valued matrices A, and B, and expect a certain result C_expect. I calculate the numerical result C_actual = A * B, using Eigen. Now, I want to compare C_expect, and C_actual. Right now, the corresponding code looks like this:

#include <complex>
#include <Eigen/Dense>
#include <gtest/gtest.h>
#include <gmock/gmock.h>

typedef std::complex<double> Complex;
typedef Eigen::Matrix2cd Matrix;

TEST(Eigen, MatrixMultiplication) {
    Matrix A, B, C_expect, C_actual;

    A << Complex(1, 1), Complex(2, 3),
         Complex(3, 2), Complex(4, 4);
    B << Complex(4, 4), Complex(3, 2),
         Complex(2, 3), Complex(1, 1);
    C_expect << Complex(-5, 20), Complex(0, 10),
                Complex(0, 40), Complex(5, 20);

    C_actual = A * B;

    // !!! These are the lines that bother me.
    for (int j = 0; j < C_actual.cols(); ++j) {
        for (int i = 0; i < C_actual.rows(); ++i) {
            EXPECT_NEAR(C_expect(i, j).real(), C_actual(i, j).real(), 1e-7)
                << "Re(" << i << "," << j << ")";
            EXPECT_NEAR(C_expect(i, j).imag(), C_actual(i, j).imag(), 1e-7)
                << "Im(" << i << "," << j << ")";
        }
    }
}

这有什么问题？好吧，我必须手动遍历矩阵的所有索引，然后分别比较实部和虚部。我更喜欢Google Mock的 ElementsAreArray 匹配器。例如，

What's wrong with this? Well, I have to manually iterate through all indices of the matrix, and then compare the real-part and imaginary-part individually. I would much prefer something along the lines of Google Mock's ElementsAreArray matcher. E.g.

EXPECT_THAT(C_actual, ElementsAreArray(C_expect));
// or
EXPECT_THAT(C_actual, Pointwise(MyComplexNear(1e-7), C_expect));

不幸的是，Google Mock的内置功能似乎只适用于一维C样式或STL型容器。此外，我需要对矩阵的复数值进行近似比较。

Unfortunately, the built-in capabilities of Google Mock only seem to work on 1-dimensional C-style, or STL-type containers. Furthermore, I need an approximate comparison for the complex values of my matrix.

我的问题：您知道吗是否可以教Google Mock在多个维度上进行迭代，并比较复杂的浮点数以近似相等？

My question: Do you know if (and how) it is possible to teach Google Mock to iterate over multiple dimensions, and compare complex floating point numbers to approximate equality?

请注意，我不能只是将数据指针作为C样式的数组进行处理，因为存储布局在 C_expect 和 C_actual 。而且，实际上，矩阵大于仅2x2矩阵。即肯定有必要进行某种循环。

Please note, that I cannot just handle the data-pointers as C-style arrays, because the storage layout might differ between C_expect, and C_actual. Also, in reality, the matrices are larger than just 2x2 matrices. I.e. some sort of loop is definitely necessary.

推荐答案

为什么不使用 isApprox 或 Eigen Matrix类型的成员函数 isMuchSmallerThan ？

以上这些函数的文档均可用此处

The documentation of these above functions are available here

因此，在大多数情况下 ASSERT_TRUE（C_actual.isApprox（C_expect））; 是您所需要的。您还可以提供一个精确度参数作为 isApprox 的第二个论据。

So for most cases ASSERT_TRUE(C_actual.isApprox(C_expect)); is what you need. You can also provide a precision parameter as the second arguement to isApprox.

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