System information (version)

• OpenCV = 3.2
• Operating System / Platform => Windows 64 Bit
• Compiler => Visual Studio 2013

Detailed description

the example of pca can take a crash, there is wrong row and col when you get value of pca eigenvalues,

Steps to reproduce

file: opencv\sources\samples\cpp\tutorial_code\ml\introduction_to_pca\introduction_to_pca.cpp
line76: eigen_val[i] = pca_analysis.eigenvalues.at(0, i);
should change to
eigen_val[i] = pca_analysis.eigenvalues.at(i, 0);