{"provider_url":"https://hatena.blog","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Frandommemory.hatenablog.com%2Fentry%2F2016%2F01%2F30%2F212344\" title=\"Fourier\u5909\u63db\uff5e\u7406\u60f3\u3068\u73fe\u5b9f - \u3089\u3093\u3060\u3080\u306a\u8a18\u61b6\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","height":"190","version":"1.0","blog_url":"https://randommemory.hatenablog.com/","url":"https://randommemory.hatenablog.com/entry/2016/01/30/212344","image_url":"http://cdn-ak.f.st-hatena.com/images/fotolife/d/derwind/20160130/20160130210657.png","type":"rich","title":"Fourier\u5909\u63db\uff5e\u7406\u60f3\u3068\u73fe\u5b9f","width":"100%","blog_title":"\u3089\u3093\u3060\u3080\u306a\u8a18\u61b6","published":"2016-01-30 21:23:44","categories":["graphics","Python","math-numerical"],"description":"$d$\u6b21\u5143Fourier\u5909\u63db\u3092 \\begin{equation} \\mathcal{F}u(\\xi) = \\frac{1}{(2\\pi)^{d/2}}\\int_{\\R^d}\\exp(- i x \\cdot \\xi) u(x) dx \\end{equation}\u3067\u5b9a\u7fa9\u3059\u308b\u3002 \u3053\u3053\u3067\u306f\u30012\u6b21\u5143Fourier\u5909\u63db\u3092\u8003\u3048\u3001$u(x) = \\chi_{[-1,1]^2}(x)$ \u3064\u307e\u308a\u3001 \\begin{equation} \\chi_{[-1,1]^2}(x) = \\begin{cases} 1, \\hspace{1em} x_1, x_2 \\in [-1,1], \\\\ 0, \\hspace{1em} \\\u2026","provider_name":"Hatena Blog","author_name":"derwind","author_url":"https://blog.hatena.ne.jp/derwind/"}