我在实施RODFT00和REDFT00. 我想将它们用于流体模拟。

对于以下问题，我将不胜感激：

1. 我已阅读文档（http://www.fftw.org/fftw3_doc/Real-even_002fodd-DFTs-_0028cosine_002fsine-transforms_0029.html#Real-even_002fodd-DFTs-_0028cosine_002fsine-transforms_0029）并且无法理解

The r2r kinds for the various REDFT and RODFT types supported by FFTW, along with the boundary conditions at both ends of the input array (n real numbers in[j=0..n-1]), are:

FFTW_REDFT00 (DCT-I): even around j=0 and even around j=n-1. FFTW_RODFT00 (DST-I): odd around j=-1 and odd around j=n.

Note that these symmetries apply to the “logical” array being transformed; there are no constraints on your physical input data.

它对余弦和正弦变换的实现有何解释？

2. 因为我想使用变换来获得微分。在这两种情况下，我应该如何安排波数与矩阵相乘？