转换向量<>到在C ++中的代码生成后的emxArray_real_T [英] Convert vector<> to emxArray_real_T in C++ after code-generation from MATLAB

问题描述

我已使用MATLAB编码器将一些matlab代码转换为C ++。

I have converted some matlab code to C++ using the MATLAB coder.

我知道有一些类似的问题，但没有解释发现确实帮助我的问题，这有点不同。

I am aware that there are some questions similar to this one, but none of the explanations I found did help with my problem, which is somewhat different.

生成的C ++代码给我以下函数：

The generated code for C++ gives me the following function:

void getTargetPoint(const emxArray_real_T *eyeMatrix, const emxArray_real_T
                *HypAlpha, const emxArray_real_T *HypCov, const
                emxArray_real_T *HypMean, const double xs[4], double Ymu[3])

其中Ymu是我正在寻找的输出。但是，即使我在转换器中将我的输入定义为不确定大小的数组，它们也是我的代码中的向量的向量：

Where Ymu is the output I am looking for. However, even if I defined my inputs as arrays of undetermined size in the converter, they are vectors of vectors in my code:

eyeMatrix = vector<vector <double>>  

它们都有不同的尺寸，例如eyeMatrix = [968x4]，但在其他情况下可以是[anything x 4]

They all have different dimensions, for instance, eyeMatrix = [968x4], but in any other case it could be [anything x 4]

我尝试了很多东西，但是我不能把我的输入数据（向量的向量）转换成类型：emxArray_real_T

I have tried many things, but I cannot manage to convert my input data (vector of vectors) into type: emxArray_real_T

有没有反正呢？或者我应该将我的输入数据转换成别的，然后进入emxArray_real_T？

Is there anyway to do this? Or should I convert my input data into something else and then into emxArray_real_T?

任何帮助或想法都非常感谢！

Any help or idea is greatly appreciated!

推荐答案

假设 eyeMatrix 是一个矩形矩阵（即每个内部向量具有相同的长度），因为生成的代码可能意味着与非乱糟糟的数组一起工作。

This answer assumes that eyeMatrix is a rectangular matrix (i.e. each inner vector has the same length) since the generated code likely is meant to work with non-ragged arrays.

您可以查看：

http://stackoverflow.com/a/24271438/3297440

和文档了解如何使用 emxArray * 数据类型。

and the documentation for an overview of working with emxArray* data types.

总结答案，你会在文件中声明函数< name> _emxAPI.h 看起来像：

To summarize the answer, you'll have functions declared in the file <name>_emxAPI.h that look like:

extern emxArray_real_T *emxCreateWrapper_real_T(double *data, int rows,
                                                int cols);
extern emxArray_real_T *emxCreate_real_T(int rows, int cols);

你会注意到第一个需要一个 double * 。

You'll notice that the first takes a double *. This should be a pointer to your data stored in column-major order.

由于 eyeMatrix 可能是以row-major顺序存储的，主要顺序并且可能不是实际连续的（我不知道保证嵌套 std :: vectors 导致连续数据）第一步可以调用 emxCreate_real_T 。

Since eyeMatrix is likely in row-major order and may not actually be contiguous (I'm not aware of a guarantee that nested std::vectors result in contiguous data) a first step can be to call emxCreate_real_T with the proper dimensions.

这会分配并返回一个 emxArray_real_T 我们可以调用 emx 。 emx-> size 将有2个元素，这是您设置的尺寸。字段 emx-> data 将是指向 rows * cols 值的指针（ double 值）。然后，您可以以列为主的方式将数据从 eyeMatrix 复制到 emx-> data 。所以如果你的矩阵是：

This allocates and returns an emxArray_real_T which we can call emx. emx->size will have 2 elements which are the dimensions you set. The field emx->data will be a pointer to rows*cols values (double values in your case). Then you can just copy the data from eyeMatrix to emx->data in a column-major fashion. So if your matrix is:

1, 2
3, 4

emx-> data 中的数据应为：

1, 3, 2, 4

从这里，只需传递 emx 作为输入。

From there, just pass emx as the input.

最后，不要忘记调用在完成 emxArray_real_T 值后，可以使用 emxDestroyArray * 函数清除任何分配的内存。

Lastly, don't forget to call the proper emxDestroyArray* functions to clean up any allocated memory when you are done with the emxArray_real_T values.

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