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        <title>Math - Category - Ubuk</title>
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        <description>Math - Category - Ubuk</description>
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            <webMaster>mymail_yjj@qq.com (o( ￣⌣￣ )o)</webMaster><lastBuildDate>Sun, 28 Jun 2026 10:06:39 &#43;0800</lastBuildDate><atom:link href="http://localhost:1313/categories/math/" rel="self" type="application/rss+xml" /><item>
    <title>高等数学笔记（上册）</title>
    <link>http://localhost:1313/posts/about_math/%E9%AB%98%E6%95%B0%E4%B8%8A/</link>
    <pubDate>Sun, 28 Jun 2026 10:06:39 &#43;0800</pubDate>
    <author>o( ￣⌣￣ )o</author>
    <guid>http://localhost:1313/posts/about_math/%E9%AB%98%E6%95%B0%E4%B8%8A/</guid>
    <description><![CDATA[<h2 id="参考资料">参考资料</h2>
<ul>
<li><a href="https://gitee.com/jason_ren/advanced-math-note/tree/main/notes" target="_blank" rel="noopener noreffer ">https://gitee.com/jason_ren/advanced-math-note/tree/main/notes</a></li>
<li><a href="https://www.cnblogs.com/ixtwuko/p/advanced-mathematics.html" target="_blank" rel="noopener noreffer ">https://www.cnblogs.com/ixtwuko/p/advanced-mathematics.html</a></li>
<li>2023版张宇考研数学基础30讲</li>
</ul>
<h1 id="第一章-函数与极限">第一章 函数与极限</h1>
<h2 id="11-函数">1.1 函数</h2>
<h3 id="函数的定义">函数的定义</h3>
<p>设 $x$ 和 $y$ 是两个变量, $D$ 是一个非空实数集。如果对于每一个 $x \in D$, 按照某个确定的对应法则 $f$, 都有 <strong>唯一确定的实数</strong> $y$ 与之对应, 则称 $f$ 为定义在 $D$ 上的 <strong>函数</strong>, 记作</p>]]></description>
</item>
<item>
    <title>数据科学</title>
    <link>http://localhost:1313/posts/about_python/%E6%95%B0%E6%8D%AE%E7%A7%91%E5%AD%A6/</link>
    <pubDate>Sat, 16 May 2026 14:31:32 &#43;0800</pubDate>
    <author>o( ￣⌣￣ )o</author>
    <guid>http://localhost:1313/posts/about_python/%E6%95%B0%E6%8D%AE%E7%A7%91%E5%AD%A6/</guid>
    <description><![CDATA[<h2 id="参考资料">参考资料</h2>
<p>Data 100 Fall 2022 website 公开课</p>
<h2 id="data-100">Data 100</h2>
<h3 id="lec-01">lec 01</h3>
<ul>
<li>
<p>读取压缩文件内容</p>
<div class="highlight"><div class="chroma">
<table class="lntable"><tr><td class="lntd">
<pre tabindex="0" class="chroma"><code><span class="lnt">1
</span><span class="lnt">2
</span><span class="lnt">3
</span><span class="lnt">4
</span><span class="lnt">5
</span><span class="lnt">6
</span></code></pre></td>
<td class="lntd">
<pre tabindex="0" class="chroma"><code class="language-python" data-lang="python"><span class="line"><span class="cl"><span class="k">with</span> <span class="n">zipfile</span><span class="o">.</span><span class="n">ZipFile</span><span class="p">(</span><span class="n">filename</span><span class="p">,</span> <span class="s2">&#34;r&#34;</span><span class="p">)</span> <span class="k">as</span> <span class="n">zf</span><span class="p">:</span>
</span></span><span class="line"><span class="cl">    <span class="c1"># 列出压缩包内的文件</span>
</span></span><span class="line"><span class="cl">    <span class="nb">print</span><span class="p">(</span><span class="n">zf</span><span class="o">.</span><span class="n">filelist</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">    <span class="n">f</span> <span class="o">=</span> <span class="s1">&#39;想要打开的文件名&#39;</span>
</span></span><span class="line"><span class="cl">    <span class="k">with</span> <span class="n">zf</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="n">f</span><span class="p">)</span> <span class="k">as</span> <span class="n">fp</span><span class="p">:</span>
</span></span><span class="line"><span class="cl">        <span class="o">......</span>
</span></span></code></pre></td></tr></table>
</div>
</div></li>
<li>
<p>透视表</p>
<div class="highlight"><div class="chroma">
<table class="lntable"><tr><td class="lntd">
<pre tabindex="0" class="chroma"><code><span class="lnt"> 1
</span><span class="lnt"> 2
</span><span class="lnt"> 3
</span><span class="lnt"> 4
</span><span class="lnt"> 5
</span><span class="lnt"> 6
</span><span class="lnt"> 7
</span><span class="lnt"> 8
</span><span class="lnt"> 9
</span><span class="lnt">10
</span></code></pre></td>
<td class="lntd">
<pre tabindex="0" class="chroma"><code class="language-python" data-lang="python"><span class="line"><span class="cl"><span class="p">(</span>
</span></span><span class="line"><span class="cl">    <span class="n">pd</span><span class="o">.</span><span class="n">pivot_table</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">        <span class="n">babynames</span><span class="p">[</span><span class="n">babynames</span><span class="p">[</span><span class="s1">&#39;Name&#39;</span><span class="p">]</span><span class="o">.</span><span class="n">isin</span><span class="p">(</span><span class="n">subset_names</span><span class="p">)],</span>
</span></span><span class="line"><span class="cl">        <span class="n">index</span><span class="o">=</span><span class="p">[</span><span class="s1">&#39;Name&#39;</span><span class="p">,</span> <span class="s1">&#39;Year&#39;</span><span class="p">],</span> <span class="n">columns</span><span class="o">=</span><span class="s1">&#39;Sex&#39;</span><span class="p">,</span> <span class="n">values</span><span class="o">=</span><span class="s1">&#39;Count&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="n">aggfunc</span><span class="o">=</span><span class="s1">&#39;sum&#39;</span><span class="p">,</span> <span class="n">fill_value</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">margins</span><span class="o">=</span><span class="kc">True</span>
</span></span><span class="line"><span class="cl">    <span class="p">)</span>
</span></span><span class="line"><span class="cl">    <span class="o">.</span><span class="n">drop</span><span class="p">(</span><span class="n">labels</span><span class="o">=</span><span class="s1">&#39;All&#39;</span><span class="p">,</span> <span class="n">level</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">axis</span><span class="o">=</span><span class="mi">0</span><span class="p">)</span> <span class="c1"># 删除汇总行</span>
</span></span><span class="line"><span class="cl">    <span class="o">.</span><span class="n">rename_axis</span><span class="p">(</span><span class="kc">None</span><span class="p">,</span> <span class="n">axis</span><span class="o">=</span><span class="mi">1</span><span class="p">)</span> <span class="c1"># 去掉列索引名</span>
</span></span><span class="line"><span class="cl">    <span class="c1"># .reset_index() # 把 (Name, Year) 从索引挪回列</span>
</span></span><span class="line"><span class="cl"><span class="p">)</span>
</span></span></code></pre></td></tr></table>
</div>
</div><p>如上, 对于过长的链式代码可以用括号包裹并分行书写, 提高可读性</p>]]></description>
</item>
<item>
    <title>常见泰勒展开公式及其推导</title>
    <link>http://localhost:1313/posts/about_math/%E5%B8%B8%E8%A7%81%E6%B3%B0%E5%8B%92%E5%B1%95%E5%BC%80%E5%85%AC%E5%BC%8F%E5%8F%8A%E5%85%B6%E6%8E%A8%E5%AF%BC/</link>
    <pubDate>Sun, 01 Mar 2026 10:58:52 &#43;0800</pubDate>
    <author>o( ￣⌣￣ )o</author>
    <guid>http://localhost:1313/posts/about_math/%E5%B8%B8%E8%A7%81%E6%B3%B0%E5%8B%92%E5%B1%95%E5%BC%80%E5%85%AC%E5%BC%8F%E5%8F%8A%E5%85%B6%E6%8E%A8%E5%AF%BC/</guid>
    <description><![CDATA[]]></description>
</item>
<item>
    <title>调整兰德指数</title>
    <link>http://localhost:1313/posts/about_math/%E8%B0%83%E6%95%B4%E5%85%B0%E5%BE%B7%E6%8C%87%E6%95%B0/</link>
    <pubDate>Sun, 18 Jan 2026 10:15:52 &#43;0800</pubDate>
    <author>o( ￣⌣￣ )o</author>
    <guid>http://localhost:1313/posts/about_math/%E8%B0%83%E6%95%B4%E5%85%B0%E5%BE%B7%E6%8C%87%E6%95%B0/</guid>
    <description><![CDATA[]]></description>
</item>
<item>
    <title>共轭梯度法</title>
    <link>http://localhost:1313/posts/about_math/%E5%85%B1%E8%BD%AD%E6%A2%AF%E5%BA%A6%E6%B3%95/</link>
    <pubDate>Thu, 25 Dec 2025 22:56:07 &#43;0800</pubDate>
    <author>o( ￣⌣￣ )o</author>
    <guid>http://localhost:1313/posts/about_math/%E5%85%B1%E8%BD%AD%E6%A2%AF%E5%BA%A6%E6%B3%95/</guid>
    <description><![CDATA[<h2 id="参考资料">参考资料</h2>
<ul>
<li><a href="https://blog.csdn.net/weixin_29732003/article/details/103433096" target="_blank" rel="noopener noreffer ">https://blog.csdn.net/weixin_29732003/article/details/103433096</a></li>
<li><a href="https://zhuanlan.zhihu.com/p/408993709" target="_blank" rel="noopener noreffer ">https://zhuanlan.zhihu.com/p/408993709</a></li>
<li><a href="https://zhuanlan.zhihu.com/p/338838078" target="_blank" rel="noopener noreffer ">https://zhuanlan.zhihu.com/p/338838078</a></li>
</ul>
<h2 id="简介">简介</h2>
<p>Conjugate Gradient Method, 简称 CG 算法，常用于求解线性方程组</p>
<h3 id="共轭梯度法的思想">共轭梯度法的思想</h3>
<p>选择一个优化方向后, 便将该方向优化到极致，后面优化的过程不再影响之前的方向的极小值<br>
这就要求每一次的优化方向都共轭正交</p>]]></description>
</item>
<item>
    <title>高等代数知识点记录</title>
    <link>http://localhost:1313/posts/about_math/%E9%AB%98%E7%AD%89%E4%BB%A3%E6%95%B0%E7%9F%A5%E8%AF%86%E7%82%B9%E8%AE%B0%E5%BD%95/</link>
    <pubDate>Sat, 24 May 2025 17:33:45 &#43;0800</pubDate>
    <author>o( ￣⌣￣ )o</author>
    <guid>http://localhost:1313/posts/about_math/%E9%AB%98%E7%AD%89%E4%BB%A3%E6%95%B0%E7%9F%A5%E8%AF%86%E7%82%B9%E8%AE%B0%E5%BD%95/</guid>
    <description><![CDATA[<h2 id="参考资料">参考资料</h2>
<ul>
<li><a href="https://linalg.apachecn.org/" target="_blank" rel="noopener noreffer ">MIT 18.06 线性代数</a></li>
<li><a href="https://gdds.jpkc.fudan.edu.cn/25968/list.htm" target="_blank" rel="noopener noreffer ">课程 PPT</a></li>
<li><a href="https://zhuanlan.zhihu.com/p/382304737" target="_blank" rel="noopener noreffer ">知乎笔记</a></li>
<li><a href="https://www.latexlive.com/" target="_blank" rel="noopener noreffer ">公式编辑器</a></li>
</ul>
<h2 id="学习目标">学习目标</h2>
<p>learning outcomes
回顾数学知识，学习思维技巧，锻炼思维能力</p>
<h2 id="多项式polynomials">多项式（Polynomials）</h2>
<h3 id="数域number-field">数域（Number Field）</h3>
<p>简单来说，一个数域是一个数的集合 $F$，满足以下条件：</p>]]></description>
</item>
<item>
    <title>概率论与数理统计笔记</title>
    <link>http://localhost:1313/posts/about_math/%E6%A6%82%E7%8E%87%E8%AE%BA%E4%B8%8E%E6%95%B0%E7%90%86%E7%BB%9F%E8%AE%A1%E7%AC%94%E8%AE%B0/</link>
    <pubDate>Sat, 24 May 2025 17:32:07 &#43;0800</pubDate>
    <author>o( ￣⌣￣ )o</author>
    <guid>http://localhost:1313/posts/about_math/%E6%A6%82%E7%8E%87%E8%AE%BA%E4%B8%8E%E6%95%B0%E7%90%86%E7%BB%9F%E8%AE%A1%E7%AC%94%E8%AE%B0/</guid>
    <description><![CDATA[<p><em>人生, 是从不充分的证据开始, 引出完美结论的一种艺术。——Samuel Bulter</em></p>
<h2 id="参考资料">参考资料</h2>
<ul>
<li><a href="https://github.com/ChanceQZ/Statistics-note" target="_blank" rel="noopener noreffer ">https://github.com/ChanceQZ/Statistics-note</a></li>
<li><a href="https://www.cnblogs.com/Renyi-Fan/p/13938385.html" target="_blank" rel="noopener noreffer ">https://www.cnblogs.com/Renyi-Fan/p/13938385.html</a></li>
<li>在线公式编辑网站：https://editor.codecogs.com/</li>
</ul>
<h2 id="事件与概率">事件与概率</h2>
<h3 id="随机试验和随机事件">随机试验和随机事件</h3>
<ul>
<li>
<p>随机现象</p>]]></description>
</item>
<item>
    <title>Lanczos 迭代算法概述</title>
    <link>http://localhost:1313/posts/about_math/lanczos%E8%BF%AD%E4%BB%A3%E7%AE%97%E6%B3%95%E6%A6%82%E8%BF%B0/</link>
    <pubDate>Sat, 15 Apr 2023 16:15:07 &#43;0800</pubDate>
    <author>o( ￣⌣￣ )o</author>
    <guid>http://localhost:1313/posts/about_math/lanczos%E8%BF%AD%E4%BB%A3%E7%AE%97%E6%B3%95%E6%A6%82%E8%BF%B0/</guid>
    <description><![CDATA[ ]]></description>
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