Matlab Codegen Eig函数-这是Bug吗? [英] Matlab Codegen Eig Function - Is this a Bug?

问题描述

请考虑以下最小示例:

function CoderEigFail() %#codegen
A = [0 sqrt(2); sqrt(2) 0];
[B C] = eig(A)

当我通过codegen CoderEigFail.m编译并运行它时，得到的矩阵B与运行原始Matlab文件时得到的矩阵不同.特别是对于mex文件，我得到B = [1 1; -1 1]，而对于Matlab文件，我得到B = [-0.7071 0.7071; 0.7071 0.7071].我在MacOSx Mountain Lion上运行了Matlab R2011a.

When I compile this via codegen CoderEigFail.m and run it, I get a different matrix B than I get when I run the original Matlab file instead. In particular, for the mex file I get B = [1 1; -1 1], while for the Matlab file I get B = [-0.7071 0.7071; 0.7071 0.7071]. I have Matlab R2011a running on MacOSx Mountain Lion.

任何人都可以重现/解释这种行为吗?这是一个错误还是我在这里错过了一些东西?

Can anyone reproduce/explain this behavior? Is this a bug or am I missing something here?

推荐答案

不，这不是bug.

正如Stuart在对该问题的评论中所指出的那样，特征向量通常被归一化. eig() .

As Stuart pointed out in the comment to the question, eigenvectors are generally normalized. This is pointed out in a note in the documentation of eig().

与已编译版本的行为差异是"".

The difference in behavior with the compiled version is a documented feature in "Expected Differences in Behavior After Compiling MATLAB Code" under "For certain advanced library functions".

这种行为只是被承认，但没有理由或解释.

This behavior is simply acknowledged but not justified or explained.

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