PCA正变换、逆变换子函数，函数精简、高效。在主函数中可以直接调用，注意在使用时应仔细阅读代码，根据实际情况正确选择子函数的返回值，保证使用正确。-PCA transformation, inverse transform subroutines, functions, streamlined and efficient. You can directly call the main function, attention should be used to read the code carefully, choosing the right according to the actual situation subroutine return values, to ensure proper use.