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import{_ as T,c as e,b as l,d as a,e as n,o as i}from"./app-C-fAkKj6.js";const p={},t={class:"MathJax",jax:"SVG",style:{position:"relative"}},Q={style:{"vertical-align":"-0.464ex"},xmlns:"http://www.w3.org/2000/svg",width:"8.951ex",height:"2.034ex",role:"img",focusable:"false",viewBox:"0 -694 3956.4 899","aria-hidden":"true"},d={class:"MathJax",jax:"SVG",style:{position:"relative"}},r={style:{"vertical-align":"-0.566ex"},xmlns:"http://www.w3.org/2000/svg",width:"28.941ex",height:"2.262ex",role:"img",focusable:"false",viewBox:"0 -750 12792 1000","aria-hidden":"true"},o={class:"MathJax",jax:"SVG",style:{position:"relative"}},c={style:{"vertical-align":"-0.186ex"},xmlns:"http://www.w3.org/2000/svg",width:"5.327ex",height:"1.756ex",role:"img",focusable:"false",viewBox:"0 -694 2354.6 776","aria-hidden":"true"},m={class:"MathJax",jax:"SVG",style:{position:"relative"}},v={style:{"vertical-align":"-0.186ex"},xmlns:"http://www.w3.org/2000/svg",width:"5.327ex",height:"1.756ex",role:"img",focusable:"false",viewBox:"0 -694 2354.6 776","aria-hidden":"true"},u={class:"MathJax",jax:"SVG",style:{position:"relative"}},h={style:{"vertical-align":"-0.566ex"},xmlns:"http://www.w3.org/2000/svg",width:"28.941ex",height:"2.262ex",role:"img",focusable:"false",viewBox:"0 -750 12792 1000","aria-hidden":"true"},g={class:"MathJax",jax:"SVG",style:{position:"relative"}},b={style:{"vertical-align":"-0.566ex"},xmlns:"http://www.w3.org/2000/svg",width:"14.585ex",height:"2.262ex",role:"img",focusable:"false",viewBox:"0 -750 6446.6 1000","aria-hidden":"true"},H={class:"MathJax",jax:"SVG",style:{position:"relative"}},f={style:{"vertical-align":"-0.566ex"},xmlns:"http://www.w3.org/2000/svg",width:"28.941ex",height:"2.262ex",role:"img",focusable:"false",viewBox:"0 -750 12792 1000","aria-hidden":"true"},L={class:"MathJax",jax:"SVG",style:{position:"relative"}},y={style:{"vertical-align":"-0.566ex"},xmlns:"http://www.w3.org/2000/svg",width:"15.716ex",height:"2.262ex",role:"img",focusable:"false",viewBox:"0 -750 6946.6 1000","aria-hidden":"true"};function B(x,s){return i(),e("div",null,[s[31]||(s[31]=l(`<h2 id="频域分析" tabindex="-1"><a class="header-anchor" href="#频域分析"><span>频域分析</span></a></h2><h3 id="conv" tabindex="-1"><a class="header-anchor" href="#conv"><span>Conv</span></a></h3><h4 id="函数简介" tabindex="-1"><a class="header-anchor" href="#函数简介"><span>函数简介</span></a></h4><p>本函数对两个输入序列进行卷积，即多项式乘法。</p><p><strong>函数名：</strong> CONV</p><p><strong>输入序列：</strong> 仅支持两个输入序列，类型均为 INT32 / INT64 / FLOAT / DOUBLE</p><p><strong>输出序列：</strong> 输出单个序列，类型为DOUBLE，它是两个序列卷积的结果。序列的时间戳从0开始，仅用于表示顺序。</p><p><strong>提示：</strong> 输入序列中的<code>NaN</code>将被忽略。</p><h4 id="使用示例" tabindex="-1"><a class="header-anchor" href="#使用示例"><span>使用示例</span></a></h4><p>输入序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+---------------+---------------+</span></span>
<span class="line"><span>| Time|root.test.d2.s1|root.test.d2.s2|</span></span>
<span class="line"><span>+-----------------------------+---------------+---------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 1.0| 7.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.001+08:00| 0.0| 2.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.002+08:00| 1.0| null|</span></span>
<span class="line"><span>+-----------------------------+---------------+---------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>用于查询的SQL语句：</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" data-title="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span style="color:#C678DD;">select</span><span style="color:#ABB2BF;"> conv(s1,s2) </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">test</span><span style="color:#ABB2BF;">.d2</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>输出序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+--------------------------------------+</span></span>
<span class="line"><span>| Time|conv(root.test.d2.s1, root.test.d2.s2)|</span></span>
<span class="line"><span>+-----------------------------+--------------------------------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 7.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.001+08:00| 2.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.002+08:00| 7.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.003+08:00| 2.0|</span></span>
<span class="line"><span>+-----------------------------+--------------------------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="deconv" tabindex="-1"><a class="header-anchor" href="#deconv"><span>Deconv</span></a></h3><h4 id="函数简介-1" tabindex="-1"><a class="header-anchor" href="#函数简介-1"><span>函数简介</span></a></h4><p>本函数对两个输入序列进行去卷积，即多项式除法运算。</p><p><strong>函数名：</strong> DECONV</p><p><strong>输入序列：</strong> 仅支持两个输入序列，类型均为 INT32 / INT64 / FLOAT / DOUBLE</p><p><strong>参数：</strong></p><ul><li><code>result</code>：去卷积的结果，取值为&#39;quotient&#39;或&#39;remainder&#39;，分别对应于去卷积的商和余数。在缺省情况下，输出去卷积的商。</li></ul><p><strong>输出序列：</strong> 输出单个序列，类型为DOUBLE。它是将第二个序列从第一个序列中去卷积（第一个序列除以第二个序列）的结果。序列的时间戳从0开始，仅用于表示顺序。</p><p><strong>提示：</strong> 输入序列中的<code>NaN</code>将被忽略。</p><h4 id="使用示例-1" tabindex="-1"><a class="header-anchor" href="#使用示例-1"><span>使用示例</span></a></h4><h5 id="计算去卷积的商" tabindex="-1"><a class="header-anchor" href="#计算去卷积的商"><span>计算去卷积的商</span></a></h5><p>当<code>result</code>参数缺省或为&#39;quotient&#39;时，本函数计算去卷积的商。</p><p>输入序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+---------------+---------------+</span></span>
<span class="line"><span>| Time|root.test.d2.s3|root.test.d2.s2|</span></span>
<span class="line"><span>+-----------------------------+---------------+---------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 8.0| 7.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.001+08:00| 2.0| 2.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.002+08:00| 7.0| null|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.003+08:00| 2.0| null|</span></span>
<span class="line"><span>+-----------------------------+---------------+---------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>用于查询的SQL语句：</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" data-title="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span style="color:#C678DD;">select</span><span style="color:#ABB2BF;"> deconv(s3,s2) </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">test</span><span style="color:#ABB2BF;">.d2</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>输出序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+----------------------------------------+</span></span>
<span class="line"><span>| Time|deconv(root.test.d2.s3, root.test.d2.s2)|</span></span>
<span class="line"><span>+-----------------------------+----------------------------------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 1.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.001+08:00| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.002+08:00| 1.0|</span></span>
<span class="line"><span>+-----------------------------+----------------------------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h5 id="计算去卷积的余数" tabindex="-1"><a class="header-anchor" href="#计算去卷积的余数"><span>计算去卷积的余数</span></a></h5><p>当<code>result</code>参数为&#39;remainder&#39;时，本函数计算去卷积的余数。输入序列同上，用于查询的SQL语句如下：</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" data-title="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span style="color:#C678DD;">select</span><span style="color:#ABB2BF;"> deconv(s3,s2,</span><span style="color:#98C379;">&#39;result&#39;</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">&#39;remainder&#39;</span><span style="color:#ABB2BF;">) </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">test</span><span style="color:#ABB2BF;">.d2</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>输出序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+--------------------------------------------------------------+</span></span>
<span class="line"><span>| Time|deconv(root.test.d2.s3, root.test.d2.s2, &quot;result&quot;=&quot;remainder&quot;)|</span></span>
<span class="line"><span>+-----------------------------+--------------------------------------------------------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 1.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.001+08:00| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.002+08:00| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.003+08:00| 0.0|</span></span>
<span class="line"><span>+-----------------------------+--------------------------------------------------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="dwt" tabindex="-1"><a class="header-anchor" href="#dwt"><span>DWT</span></a></h3><h4 id="函数简介-2" tabindex="-1"><a class="header-anchor" href="#函数简介-2"><span>函数简介</span></a></h4><p>本函数对输入序列进行一维离散小波变换。</p><p><strong>函数名：</strong> DWT</p><p><strong>输入序列：</strong> 仅支持单个输入序列，类型为 INT32 / INT64 / FLOAT / DOUBLE</p><p><strong>参数：</strong></p>`,44)),a("ul",null,[s[5]||(s[5]=a("li",null,[a("code",null,"method"),n("：小波滤波的类型，提供'Haar', 'DB4', 'DB6', 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<span class="line"><span>| Time|root.test.d1.s1|</span></span>
<span class="line"><span>+-----------------------------+---------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.100+08:00| 0.2|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.200+08:00| 1.5|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.300+08:00| 1.2|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.400+08:00| 0.6|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.500+08:00| 1.7|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.600+08:00| 0.8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.700+08:00| 2.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.800+08:00| 2.5|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.900+08:00| 2.1|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.000+08:00| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.100+08:00| 2.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.200+08:00| 1.8|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.300+08:00| 1.2|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.400+08:00| 1.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.500+08:00| 1.6|</span></span>
<span class="line"><span>+-----------------------------+---------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>用于查询的SQL语句：</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" data-title="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span style="color:#C678DD;">select</span><span style="color:#ABB2BF;"> dwt(s1,</span><span style="color:#98C379;">&quot;method&quot;</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">&quot;haar&quot;</span><span style="color:#ABB2BF;">) </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">test</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>输出序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+-------------------------------------+</span></span>
<span class="line"><span>| Time|dwt(root.test.d1.s1, &quot;method&quot;=&quot;haar&quot;)|</span></span>
<span class="line"><span>+-----------------------------+-------------------------------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 0.14142135834465192|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.100+08:00| 1.909188342921157|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.200+08:00| 1.6263456473052773|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.300+08:00| 1.9798989957517026|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.400+08:00| 3.252691126023161|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.500+08:00| 1.414213562373095|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.600+08:00| 2.1213203435596424|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.700+08:00| 1.8384776479437628|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.800+08:00| -0.14142135834465192|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.900+08:00| 0.21213200063848547|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.000+08:00| -0.7778174761639416|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.100+08:00| -0.8485281289944873|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.200+08:00| 0.2828427799095765|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.300+08:00| -1.414213562373095|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.400+08:00| 0.42426400127697095|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.500+08:00| -0.42426408557066786|</span></span>
<span class="line"><span>+-----------------------------+-------------------------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="fft" tabindex="-1"><a class="header-anchor" href="#fft"><span>FFT</span></a></h3><h4 id="函数简介-3" tabindex="-1"><a class="header-anchor" href="#函数简介-3"><span>函数简介</span></a></h4><p>本函数对输入序列进行快速傅里叶变换。</p><p><strong>函数名：</strong> FFT</p><p><strong>输入序列：</strong> 仅支持单个输入序列，类型为 INT32 / INT64 / FLOAT / DOUBLE</p><p><strong>参数：</strong></p><ul><li><code>method</code>：傅里叶变换的类型，取值为&#39;uniform&#39;或&#39;nonuniform&#39;，缺省情况下为&#39;uniform&#39;。当取值为&#39;uniform&#39;时，时间戳将被忽略，所有数据点都将被视作等距的，并应用等距快速傅里叶算法；当取值为&#39;nonuniform&#39;时，将根据时间戳应用非等距快速傅里叶算法（未实现）。</li><li><code>result</code>：傅里叶变换的结果，取值为&#39;real&#39;、&#39;imag&#39;、&#39;abs&#39;或&#39;angle&#39;，分别对应于变换结果的实部、虚部、模和幅角。在缺省情况下，输出变换的模。</li><li><code>compress</code>：压缩参数，取值范围(0,1]，是有损压缩时保留的能量比例。在缺省情况下，不进行压缩。</li></ul><p><strong>输出序列：</strong> 输出单个序列，类型为DOUBLE，长度与输入相等。序列的时间戳从0开始，仅用于表示顺序。</p><p><strong>提示：</strong> 输入序列中的<code>NaN</code>将被忽略。</p><h4 id="使用示例-3" tabindex="-1"><a class="header-anchor" href="#使用示例-3"><span>使用示例</span></a></h4><h5 id="等距傅里叶变换" tabindex="-1"><a class="header-anchor" href="#等距傅里叶变换"><span>等距傅里叶变换</span></a></h5><p>当<code>type</code>参数缺省或为&#39;uniform&#39;时，本函数进行等距傅里叶变换。</p><p>输入序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+---------------+</span></span>
<span class="line"><span>| Time|root.test.d1.s1|</span></span>
<span class="line"><span>+-----------------------------+---------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 2.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.000+08:00| 1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:02.000+08:00| -2.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:03.000+08:00| -1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:04.000+08:00| 1.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:05.000+08:00| 1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:06.000+08:00| 0.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:07.000+08:00| -1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:08.000+08:00| -0.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:09.000+08:00| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:10.000+08:00| 0.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:11.000+08:00| 1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:12.000+08:00| -0.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:13.000+08:00| -1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:14.000+08:00| -1.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:15.000+08:00| 1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:16.000+08:00| 2.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:17.000+08:00| -1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:18.000+08:00| -2.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:19.000+08:00| 0.0|</span></span>
<span class="line"><span>+-----------------------------+---------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>用于查询的SQL语句：</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" data-title="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span style="color:#C678DD;">select</span><span style="color:#ABB2BF;"> fft(s1) </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">test</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>输出序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+----------------------+</span></span>
<span class="line"><span>| Time| fft(root.test.d1.s1)|</span></span>
<span class="line"><span>+-----------------------------+----------------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.001+08:00| 1.2727111142703152E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.002+08:00| 2.385520799101839E-7|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.003+08:00| 8.723291723972645E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.004+08:00| 19.999999960195904|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.005+08:00| 9.999999850988388|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.006+08:00| 3.2260694930700566E-7|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.007+08:00| 8.723291605373329E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.008+08:00| 1.108657103979944E-7|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.009+08:00| 1.2727110997246171E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.010+08:00|1.9852334701272664E-23|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.011+08:00| 1.2727111194499847E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.012+08:00| 1.108657103979944E-7|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.013+08:00| 8.723291785769131E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.014+08:00| 3.226069493070057E-7|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.015+08:00| 9.999999850988388|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.016+08:00| 19.999999960195904|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.017+08:00| 8.723291747109068E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.018+08:00| 2.3855207991018386E-7|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.019+08:00| 1.2727112069910878E-8|</span></span>
<span class="line"><span>+-----------------------------+----------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div>`,28)),a("p",null,[s[13]||(s[13]=n("注：输入序列服从")),a("mjx-container",d,[(i(),e("svg",r,s[7]||(s[7]=[l('<g stroke="currentColor" fill="currentColor" stroke-width="0" transform="scale(1,-1)"><g data-mml-node="math"><g data-mml-node="mi"><path data-c="1D466" d="M21 287Q21 301 36 335T84 406T158 442Q199 442 224 419T250 355Q248 336 247 334Q247 331 231 288T198 191T182 105Q182 62 196 45T238 27Q261 27 281 38T312 61T339 94Q339 95 344 114T358 173T377 247Q415 397 419 404Q432 431 462 431Q475 431 483 424T494 412T496 403Q496 390 447 193T391 -23Q363 -106 294 -155T156 -205Q111 -205 77 -183T43 -117Q43 -95 50 -80T69 -58T89 -48T106 -45Q150 -45 150 -87Q150 -107 138 -122T115 -142T102 -147L99 -148Q101 -153 118 -160T152 -167H160Q177 -167 186 -165Q219 -156 247 -127T290 -65T313 -9T321 21L315 17Q309 13 296 6T270 -6Q250 -11 231 -11Q185 -11 150 11T104 82Q103 89 103 113Q103 170 138 262T173 379Q173 380 173 381Q173 390 173 393T169 400T158 404H154Q131 404 112 385T82 344T65 302T57 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class="line"><span style="color:#C678DD;">select</span><span style="color:#ABB2BF;"> fft(s1, </span><span style="color:#98C379;">&#39;result&#39;</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">&#39;real&#39;</span><span style="color:#ABB2BF;">, </span><span style="color:#98C379;">&#39;compress&#39;</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">&#39;0.99&#39;</span><span style="color:#ABB2BF;">), fft(s1, </span><span style="color:#98C379;">&#39;result&#39;</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">&#39;imag&#39;</span><span style="color:#ABB2BF;">,</span><span style="color:#98C379;">&#39;compress&#39;</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">&#39;0.99&#39;</span><span style="color:#ABB2BF;">) </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">test</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>输出序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+----------------------+----------------------+</span></span>
<span class="line"><span>| Time| fft(root.test.d1.s1,| fft(root.test.d1.s1,|</span></span>
<span class="line"><span>| | &quot;result&quot;=&quot;real&quot;,| &quot;result&quot;=&quot;imag&quot;,|</span></span>
<span class="line"><span>| | &quot;compress&quot;=&quot;0.99&quot;)| &quot;compress&quot;=&quot;0.99&quot;)|</span></span>
<span class="line"><span>+-----------------------------+----------------------+----------------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 0.0| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.001+08:00| -3.932894010461041E-9| 1.2104201863039066E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.002+08:00|-1.4021739447490164E-7| 1.9299268669082926E-7|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.003+08:00| -7.057291240286645E-8| 5.127422242345858E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.004+08:00| 19.021130288047125| -6.180339875198807|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.005+08:00| 9.999999850988388| 3.501852745067114E-16|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.019+08:00| -3.932894898639461E-9|-1.2104202549376264E-8|</span></span>
<span class="line"><span>+-----------------------------+----------------------+----------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>注：基于傅里叶变换结果的共轭性质，压缩结果只保留前一半；根据给定的压缩参数，从低频到高频保留数据点，直到保留的能量比例超过该值；保留最后一个数据点以表示序列长度。</p><h3 id="highpass" tabindex="-1"><a class="header-anchor" href="#highpass"><span>HighPass</span></a></h3><h4 id="函数简介-4" tabindex="-1"><a class="header-anchor" href="#函数简介-4"><span>函数简介</span></a></h4><p>本函数对输入序列进行高通滤波，提取高于截止频率的分量。输入序列的时间戳将被忽略，所有数据点都将被视作等距的。</p><p><strong>函数名：</strong> HIGHPASS</p><p><strong>输入序列：</strong> 仅支持单个输入序列，类型为 INT32 / INT64 / FLOAT / DOUBLE</p><p><strong>参数：</strong></p><ul><li><code>wpass</code>：归一化后的截止频率，取值为(0,1)，不可缺省。</li></ul><p><strong>输出序列：</strong> 输出单个序列，类型为DOUBLE，它是滤波后的序列，长度与时间戳均与输入一致。</p><p><strong>提示：</strong> 输入序列中的<code>NaN</code>将被忽略。</p><h4 id="使用示例-4" tabindex="-1"><a class="header-anchor" href="#使用示例-4"><span>使用示例</span></a></h4><p>输入序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+---------------+</span></span>
<span class="line"><span>| Time|root.test.d1.s1|</span></span>
<span class="line"><span>+-----------------------------+---------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 2.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.000+08:00| 1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:02.000+08:00| -2.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:03.000+08:00| -1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:04.000+08:00| 1.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:05.000+08:00| 1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:06.000+08:00| 0.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:07.000+08:00| -1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:08.000+08:00| -0.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:09.000+08:00| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:10.000+08:00| 0.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:11.000+08:00| 1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:12.000+08:00| -0.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:13.000+08:00| -1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:14.000+08:00| -1.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:15.000+08:00| 1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:16.000+08:00| 2.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:17.000+08:00| -1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:18.000+08:00| -2.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:19.000+08:00| 0.0|</span></span>
<span class="line"><span>+-----------------------------+---------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>用于查询的SQL语句：</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" data-title="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span style="color:#C678DD;">select</span><span style="color:#ABB2BF;"> highpass(s1,</span><span style="color:#98C379;">&#39;wpass&#39;</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">&#39;0.45&#39;</span><span style="color:#ABB2BF;">) </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">test</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>输出序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+-----------------------------------------+</span></span>
<span class="line"><span>| Time|highpass(root.test.d1.s1, &quot;wpass&quot;=&quot;0.45&quot;)|</span></span>
<span class="line"><span>+-----------------------------+-----------------------------------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 0.9999999534830373|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.000+08:00| 1.7462829277628608E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:02.000+08:00| -0.9999999593178128|</span></span>
<span class="line"><span>|1970-01-01T08:00:03.000+08:00| -4.1115269056426626E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:04.000+08:00| 0.9999999925494194|</span></span>
<span class="line"><span>|1970-01-01T08:00:05.000+08:00| 3.328126513330016E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:06.000+08:00| -1.0000000183304454|</span></span>
<span class="line"><span>|1970-01-01T08:00:07.000+08:00| 6.260191433311374E-10|</span></span>
<span class="line"><span>|1970-01-01T08:00:08.000+08:00| 1.0000000018134796|</span></span>
<span class="line"><span>|1970-01-01T08:00:09.000+08:00| -3.097210911744423E-17|</span></span>
<span class="line"><span>|1970-01-01T08:00:10.000+08:00| -1.0000000018134794|</span></span>
<span class="line"><span>|1970-01-01T08:00:11.000+08:00| -6.260191627862097E-10|</span></span>
<span class="line"><span>|1970-01-01T08:00:12.000+08:00| 1.0000000183304454|</span></span>
<span class="line"><span>|1970-01-01T08:00:13.000+08:00| -3.328126501424346E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:14.000+08:00| -0.9999999925494196|</span></span>
<span class="line"><span>|1970-01-01T08:00:15.000+08:00| 4.111526915498874E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:16.000+08:00| 0.9999999593178128|</span></span>
<span class="line"><span>|1970-01-01T08:00:17.000+08:00| -1.7462829341296528E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:18.000+08:00| -0.9999999534830369|</span></span>
<span class="line"><span>|1970-01-01T08:00:19.000+08:00| -1.035237222742873E-16|</span></span>
<span class="line"><span>+-----------------------------+-----------------------------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div 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750 438 744T444 730Q444 725 271 248T92 -240Q85 -250 75 -250Q68 -250 62 -245T56 -231Q56 -221 230 257T407 740Q411 750 423 750Z"></path></g></g><g data-mml-node="mn" transform="translate(5557.6,0)"><path data-c="34" d="M462 0Q444 3 333 3Q217 3 199 0H190V46H221Q241 46 248 46T265 48T279 53T286 61Q287 63 287 115V165H28V211L179 442Q332 674 334 675Q336 677 355 677H373L379 671V211H471V165H379V114Q379 73 379 66T385 54Q393 47 442 46H471V0H462ZM293 211V545L74 212L183 211H293Z"></path></g><g data-mml-node="mo" transform="translate(6057.6,0)"><path data-c="29" d="M60 749L64 750Q69 750 74 750H86L114 726Q208 641 251 514T294 250Q294 182 284 119T261 12T224 -76T186 -143T145 -194T113 -227T90 -246Q87 -249 86 -250H74Q66 -250 63 -250T58 -247T55 -238Q56 -237 66 -225Q221 -64 221 250T66 725Q56 737 55 738Q55 746 60 749Z"></path></g></g></g>',1)]))),s[20]||(s[20]=a("mjx-assistive-mml",{unselectable:"on",display:"inline"},[a("math",{xmlns:"http://www.w3.org/1998/Math/MathML"},[a("mi",null,"y"),a("mo",null,"="),a("mi",null,"s"),a("mi",null,"i"),a("mi",null,"n"),a("mo",{stretchy:"false"},"("),a("mn",null,"2"),a("mi",null,"π"),a("mi",null,"t"),a("mrow",{"data-mjx-texclass":"ORD"},[a("mo",null,"/")]),a("mn",null,"4"),a("mo",{stretchy:"false"},")")])],-1))]),s[23]||(s[23]=n("。"))]),s[34]||(s[34]=l(`<h3 id="ifft" tabindex="-1"><a class="header-anchor" href="#ifft"><span>IFFT</span></a></h3><h4 id="函数简介-5" tabindex="-1"><a class="header-anchor" href="#函数简介-5"><span>函数简介</span></a></h4><p>本函数将输入的两个序列作为实部和虚部视作一个复数，进行逆快速傅里叶变换，并输出结果的实部。输入数据的格式参见<code>FFT</code>函数的输出，并支持以<code>FFT</code>函数压缩后的输出作为本函数的输入。</p><p><strong>函数名：</strong> IFFT</p><p><strong>输入序列：</strong> 仅支持两个输入序列，类型均为 INT32 / INT64 / FLOAT / DOUBLE</p><p><strong>参数：</strong></p><ul><li><code>start</code>：输出序列的起始时刻，是一个格式为&#39;yyyy-MM-dd HH:mm:ss&#39;的时间字符串。在缺省情况下，为&#39;1970-01-01 08:00:00&#39;。</li><li><code>interval</code>：输出序列的时间间隔，是一个有单位的正数。目前支持五种单位，分别是&#39;ms&#39;（毫秒）、&#39;s&#39;（秒）、&#39;m&#39;（分钟）、&#39;h&#39;（小时）和&#39;d&#39;（天）。在缺省情况下，为1s。</li></ul><p><strong>输出序列：</strong> 输出单个序列，类型为DOUBLE。该序列是一个等距时间序列，它的值是将两个输入序列依次作为实部和虚部进行逆快速傅里叶变换的结果。</p><p><strong>提示：</strong> 如果某行数据中包含空值或<code>NaN</code>，该行数据将会被忽略。</p><h4 id="使用示例-5" tabindex="-1"><a class="header-anchor" href="#使用示例-5"><span>使用示例</span></a></h4><p>输入序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+----------------------+----------------------+</span></span>
<span class="line"><span>| Time| root.test.d1.re| root.test.d1.im|</span></span>
<span class="line"><span>+-----------------------------+----------------------+----------------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 0.0| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.001+08:00| -3.932894010461041E-9| 1.2104201863039066E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.002+08:00|-1.4021739447490164E-7| 1.9299268669082926E-7|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.003+08:00| -7.057291240286645E-8| 5.127422242345858E-8|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.004+08:00| 19.021130288047125| -6.180339875198807|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.005+08:00| 9.999999850988388| 3.501852745067114E-16|</span></span>
<span class="line"><span>|1970-01-01T08:00:00.019+08:00| -3.932894898639461E-9|-1.2104202549376264E-8|</span></span>
<span class="line"><span>+-----------------------------+----------------------+----------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>用于查询的SQL语句：</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" data-title="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span style="color:#C678DD;">select</span><span style="color:#ABB2BF;"> ifft(re, im, </span><span style="color:#98C379;">&#39;interval&#39;</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">&#39;1m&#39;</span><span style="color:#ABB2BF;">, </span><span style="color:#98C379;">&#39;start&#39;</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">&#39;2021-01-01 00:00:00&#39;</span><span style="color:#ABB2BF;">) </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">test</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>输出序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+-------------------------------------------------------+</span></span>
<span class="line"><span>| Time|ifft(root.test.d1.re, root.test.d1.im, &quot;interval&quot;=&quot;1m&quot;,|</span></span>
<span class="line"><span>| | &quot;start&quot;=&quot;2021-01-01 00:00:00&quot;)|</span></span>
<span class="line"><span>+-----------------------------+-------------------------------------------------------+</span></span>
<span class="line"><span>|2021-01-01T00:00:00.000+08:00| 2.902112992431231|</span></span>
<span class="line"><span>|2021-01-01T00:01:00.000+08:00| 1.1755704705132448|</span></span>
<span class="line"><span>|2021-01-01T00:02:00.000+08:00| -2.175570513757101|</span></span>
<span class="line"><span>|2021-01-01T00:03:00.000+08:00| -1.9021130389094498|</span></span>
<span class="line"><span>|2021-01-01T00:04:00.000+08:00| 0.9999999925494194|</span></span>
<span class="line"><span>|2021-01-01T00:05:00.000+08:00| 1.902113046743454|</span></span>
<span class="line"><span>|2021-01-01T00:06:00.000+08:00| 0.17557053610884188|</span></span>
<span class="line"><span>|2021-01-01T00:07:00.000+08:00| -1.1755704886020932|</span></span>
<span class="line"><span>|2021-01-01T00:08:00.000+08:00| -0.9021130371347148|</span></span>
<span class="line"><span>|2021-01-01T00:09:00.000+08:00| 3.552713678800501E-16|</span></span>
<span class="line"><span>|2021-01-01T00:10:00.000+08:00| 0.9021130371347154|</span></span>
<span class="line"><span>|2021-01-01T00:11:00.000+08:00| 1.1755704886020932|</span></span>
<span class="line"><span>|2021-01-01T00:12:00.000+08:00| -0.17557053610884144|</span></span>
<span class="line"><span>|2021-01-01T00:13:00.000+08:00| -1.902113046743454|</span></span>
<span class="line"><span>|2021-01-01T00:14:00.000+08:00| -0.9999999925494196|</span></span>
<span class="line"><span>|2021-01-01T00:15:00.000+08:00| 1.9021130389094498|</span></span>
<span class="line"><span>|2021-01-01T00:16:00.000+08:00| 2.1755705137571004|</span></span>
<span class="line"><span>|2021-01-01T00:17:00.000+08:00| -1.1755704705132448|</span></span>
<span class="line"><span>|2021-01-01T00:18:00.000+08:00| -2.902112992431231|</span></span>
<span class="line"><span>|2021-01-01T00:19:00.000+08:00| -3.552713678800501E-16|</span></span>
<span class="line"><span>+-----------------------------+-------------------------------------------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="lowpass" tabindex="-1"><a class="header-anchor" href="#lowpass"><span>LowPass</span></a></h3><h4 id="函数简介-6" tabindex="-1"><a class="header-anchor" href="#函数简介-6"><span>函数简介</span></a></h4><p>本函数对输入序列进行低通滤波，提取低于截止频率的分量。输入序列的时间戳将被忽略，所有数据点都将被视作等距的。</p><p><strong>函数名：</strong> LOWPASS</p><p><strong>输入序列：</strong> 仅支持单个输入序列，类型为 INT32 / INT64 / FLOAT / DOUBLE</p><p><strong>参数：</strong></p><ul><li><code>wpass</code>：归一化后的截止频率，取值为(0,1)，不可缺省。</li></ul><p><strong>输出序列：</strong> 输出单个序列，类型为DOUBLE，它是滤波后的序列，长度与时间戳均与输入一致。</p><p><strong>提示：</strong> 输入序列中的<code>NaN</code>将被忽略。</p><h4 id="使用示例-6" tabindex="-1"><a class="header-anchor" href="#使用示例-6"><span>使用示例</span></a></h4><p>输入序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+---------------+</span></span>
<span class="line"><span>| Time|root.test.d1.s1|</span></span>
<span class="line"><span>+-----------------------------+---------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 2.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.000+08:00| 1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:02.000+08:00| -2.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:03.000+08:00| -1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:04.000+08:00| 1.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:05.000+08:00| 1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:06.000+08:00| 0.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:07.000+08:00| -1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:08.000+08:00| -0.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:09.000+08:00| 0.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:10.000+08:00| 0.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:11.000+08:00| 1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:12.000+08:00| -0.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:13.000+08:00| -1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:14.000+08:00| -1.0|</span></span>
<span class="line"><span>|1970-01-01T08:00:15.000+08:00| 1.9021131|</span></span>
<span class="line"><span>|1970-01-01T08:00:16.000+08:00| 2.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:17.000+08:00| -1.1755705|</span></span>
<span class="line"><span>|1970-01-01T08:00:18.000+08:00| -2.902113|</span></span>
<span class="line"><span>|1970-01-01T08:00:19.000+08:00| 0.0|</span></span>
<span class="line"><span>+-----------------------------+---------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>用于查询的SQL语句：</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" data-title="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span style="color:#C678DD;">select</span><span style="color:#ABB2BF;"> lowpass(s1,</span><span style="color:#98C379;">&#39;wpass&#39;</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">&#39;0.45&#39;</span><span style="color:#ABB2BF;">) </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">test</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>输出序列：</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" data-title="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code><span class="line"><span>+-----------------------------+----------------------------------------+</span></span>
<span class="line"><span>| Time|lowpass(root.test.d1.s1, &quot;wpass&quot;=&quot;0.45&quot;)|</span></span>
<span class="line"><span>+-----------------------------+----------------------------------------+</span></span>
<span class="line"><span>|1970-01-01T08:00:00.000+08:00| 1.9021130073323922|</span></span>
<span class="line"><span>|1970-01-01T08:00:01.000+08:00| 1.1755704705132448|</span></span>
<span class="line"><span>|1970-01-01T08:00:02.000+08:00| -1.1755705286582614|</span></span>
<span class="line"><span>|1970-01-01T08:00:03.000+08:00| -1.9021130389094498|</span></span>
<span class="line"><span>|1970-01-01T08:00:04.000+08:00| 7.450580419288145E-9|</span></span>
<span class="line"><span>|1970-01-01T08:00:05.000+08:00| 1.902113046743454|</span></span>
<span class="line"><span>|1970-01-01T08:00:06.000+08:00| 1.1755705212076808|</span></span>
<span class="line"><span>|1970-01-01T08:00:07.000+08:00| -1.1755704886020932|</span></span>
<span class="line"><span>|1970-01-01T08:00:08.000+08:00| -1.9021130222335536|</span></span>
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