Abstract: Since its introduction in 1965 by Cooley and Tukey, the Fast Fourier Transform (FFT) has revolutionized signal processing, converting time domain data into frequency domain data with ...

フーリエ変換とその周辺の理解を深めるためにRでシミュレーションをおこなった。まず$${f(x)}$$という関数のフーリエ級数展開を数式で書くと、 $${f(x) = \frac{a_0}{2} + \sum_{k=1}^\infty (a_k cos(k \theta x) + b_k cos(k \theta x)) (k\in\mathbb{N}, \theta\in\mathbb{R}^{+ ...

Abstract: As a matter of fact, for a widely used and efficient mathematical tool with long history of development, Fast Fourier Transform plays an important role in so many disciplines as well as ...

The prediction of the properties of crystal materials has always been a core issue in materials science and solid-state physics. With the rapid development of computer simulation techniques and ...