api-docs/crates-enclave/src/rusty_machine/data/transforms/minmax.rs.html - incubator-teaclave-website - Git at Google

 <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/git/checkouts/incubator-teaclave-crates-c8106113f74feefc/ede1f68/rusty-machine/src/data/transforms/minmax.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>minmax.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../../normalize.css"><link rel="stylesheet" href="../../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../../ayu.css" disabled><link rel="stylesheet" href="../../../../dark.css" disabled><link rel="stylesheet" href="../../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../../storage.js"></script><script defer src="../../../../source-script.js"></script><script defer src="../../../../source-files.js"></script><script defer src="../../../../main.js"></script><noscript><link rel="stylesheet" href="../../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../../rusty_machine/index.html"><div class="logo-container"><img class="rust-logo" src="../../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../../rusty_machine/index.html"><img class="rust-logo" src="../../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span>
 <span id="2">2</span>
 <span id="3">3</span>
 <span id="4">4</span>
 <span id="5">5</span>
 <span id="6">6</span>
 <span id="7">7</span>
 <span id="8">8</span>
 <span id="9">9</span>
 <span id="10">10</span>
 <span id="11">11</span>
 <span id="12">12</span>
 <span id="13">13</span>
 <span id="14">14</span>
 <span id="15">15</span>
 <span id="16">16</span>
 <span id="17">17</span>
 <span id="18">18</span>
 <span id="19">19</span>
 <span id="20">20</span>
 <span id="21">21</span>
 <span id="22">22</span>
 <span id="23">23</span>
 <span id="24">24</span>
 <span id="25">25</span>
 <span id="26">26</span>
 <span id="27">27</span>
 <span id="28">28</span>
 <span id="29">29</span>
 <span id="30">30</span>
 <span id="31">31</span>
 <span id="32">32</span>
 <span id="33">33</span>
 <span id="34">34</span>
 <span id="35">35</span>
 <span id="36">36</span>
 <span id="37">37</span>
 <span id="38">38</span>
 <span id="39">39</span>
 <span id="40">40</span>
 <span id="41">41</span>
 <span id="42">42</span>
 <span id="43">43</span>
 <span id="44">44</span>
 <span id="45">45</span>
 <span id="46">46</span>
 <span id="47">47</span>
 <span id="48">48</span>
 <span id="49">49</span>
 <span id="50">50</span>
 <span id="51">51</span>
 <span id="52">52</span>
 <span id="53">53</span>
 <span id="54">54</span>
 <span id="55">55</span>
 <span id="56">56</span>
 <span id="57">57</span>
 <span id="58">58</span>
 <span id="59">59</span>
 <span id="60">60</span>
 <span id="61">61</span>
 <span id="62">62</span>
 <span id="63">63</span>
 <span id="64">64</span>
 <span id="65">65</span>
 <span id="66">66</span>
 <span id="67">67</span>
 <span id="68">68</span>
 <span id="69">69</span>
 <span id="70">70</span>
 <span id="71">71</span>
 <span id="72">72</span>
 <span id="73">73</span>
 <span id="74">74</span>
 <span id="75">75</span>
 <span id="76">76</span>
 <span id="77">77</span>
 <span id="78">78</span>
 <span id="79">79</span>
 <span id="80">80</span>
 <span id="81">81</span>
 <span id="82">82</span>
 <span id="83">83</span>
 <span id="84">84</span>
 <span id="85">85</span>
 <span id="86">86</span>
 <span id="87">87</span>
 <span id="88">88</span>
 <span id="89">89</span>
 <span id="90">90</span>
 <span id="91">91</span>
 <span id="92">92</span>
 <span id="93">93</span>
 <span id="94">94</span>
 <span id="95">95</span>
 <span id="96">96</span>
 <span id="97">97</span>
 <span id="98">98</span>
 <span id="99">99</span>
 <span id="100">100</span>
 <span id="101">101</span>
 <span id="102">102</span>
 <span id="103">103</span>
 <span id="104">104</span>
 <span id="105">105</span>
 <span id="106">106</span>
 <span id="107">107</span>
 <span id="108">108</span>
 <span id="109">109</span>
 <span id="110">110</span>
 <span id="111">111</span>
 <span id="112">112</span>
 <span id="113">113</span>
 <span id="114">114</span>
 <span id="115">115</span>
 <span id="116">116</span>
 <span id="117">117</span>
 <span id="118">118</span>
 <span id="119">119</span>
 <span id="120">120</span>
 <span id="121">121</span>
 <span id="122">122</span>
 <span id="123">123</span>
 <span id="124">124</span>
 <span id="125">125</span>
 <span id="126">126</span>
 <span id="127">127</span>
 <span id="128">128</span>
 <span id="129">129</span>
 <span id="130">130</span>
 <span id="131">131</span>
 <span id="132">132</span>
 <span id="133">133</span>
 <span id="134">134</span>
 <span id="135">135</span>
 <span id="136">136</span>
 <span id="137">137</span>
 <span id="138">138</span>
 <span id="139">139</span>
 <span id="140">140</span>
 <span id="141">141</span>
 <span id="142">142</span>
 <span id="143">143</span>
 <span id="144">144</span>
 <span id="145">145</span>
 <span id="146">146</span>
 <span id="147">147</span>
 <span id="148">148</span>
 <span id="149">149</span>
 <span id="150">150</span>
 <span id="151">151</span>
 <span id="152">152</span>
 <span id="153">153</span>
 <span id="154">154</span>
 <span id="155">155</span>
 <span id="156">156</span>
 <span id="157">157</span>
 <span id="158">158</span>
 <span id="159">159</span>
 <span id="160">160</span>
 <span id="161">161</span>
 <span id="162">162</span>
 <span id="163">163</span>
 <span id="164">164</span>
 <span id="165">165</span>
 <span id="166">166</span>
 <span id="167">167</span>
 <span id="168">168</span>
 <span id="169">169</span>
 <span id="170">170</span>
 <span id="171">171</span>
 <span id="172">172</span>
 <span id="173">173</span>
 <span id="174">174</span>
 <span id="175">175</span>
 <span id="176">176</span>
 <span id="177">177</span>
 <span id="178">178</span>
 <span id="179">179</span>
 <span id="180">180</span>
 <span id="181">181</span>
 <span id="182">182</span>
 <span id="183">183</span>
 <span id="184">184</span>
 <span id="185">185</span>
 <span id="186">186</span>
 <span id="187">187</span>
 <span id="188">188</span>
 <span id="189">189</span>
 <span id="190">190</span>
 <span id="191">191</span>
 <span id="192">192</span>
 <span id="193">193</span>
 <span id="194">194</span>
 <span id="195">195</span>
 <span id="196">196</span>
 <span id="197">197</span>
 <span id="198">198</span>
 <span id="199">199</span>
 <span id="200">200</span>
 <span id="201">201</span>
 <span id="202">202</span>
 <span id="203">203</span>
 <span id="204">204</span>
 <span id="205">205</span>
 <span id="206">206</span>
 <span id="207">207</span>
 <span id="208">208</span>
 <span id="209">209</span>
 <span id="210">210</span>
 <span id="211">211</span>
 <span id="212">212</span>
 <span id="213">213</span>
 <span id="214">214</span>
 <span id="215">215</span>
 <span id="216">216</span>
 <span id="217">217</span>
 <span id="218">218</span>
 <span id="219">219</span>
 <span id="220">220</span>
 <span id="221">221</span>
 <span id="222">222</span>
 <span id="223">223</span>
 <span id="224">224</span>
 <span id="225">225</span>
 <span id="226">226</span>
 <span id="227">227</span>
 <span id="228">228</span>
 <span id="229">229</span>
 <span id="230">230</span>
 <span id="231">231</span>
 <span id="232">232</span>
 <span id="233">233</span>
 <span id="234">234</span>
 <span id="235">235</span>
 <span id="236">236</span>
 <span id="237">237</span>
 <span id="238">238</span>
 <span id="239">239</span>
 <span id="240">240</span>
 <span id="241">241</span>
 <span id="242">242</span>
 <span id="243">243</span>
 <span id="244">244</span>
 <span id="245">245</span>
 <span id="246">246</span>
 <span id="247">247</span>
 <span id="248">248</span>
 <span id="249">249</span>
 <span id="250">250</span>
 <span id="251">251</span>
 <span id="252">252</span>
 <span id="253">253</span>
 <span id="254">254</span>
 <span id="255">255</span>
 <span id="256">256</span>
 <span id="257">257</span>
 <span id="258">258</span>
 <span id="259">259</span>
 <span id="260">260</span>
 <span id="261">261</span>
 <span id="262">262</span>
 <span id="263">263</span>
 <span id="264">264</span>
 <span id="265">265</span>
 <span id="266">266</span>
 <span id="267">267</span>
 </pre><pre class="rust"><code><span class="doccomment">//! The Min-Max transformer
 //!
 //! This module contains the `MinMaxScaler` transformer.
 //!
 //! The `MinMaxScaler` transformer is used to transform input data
 //! so that the minimum and maximum of each column are as specified.
 //! This is commonly used to transform the data to have a minimum of
 //! `0` and a maximum of `1`.
 //!
 //! # Examples
 //!
 //! ```
 //! use rusty_machine::data::transforms::{Transformer, TransformFitter, MinMaxFitter};
 //! use rusty_machine::linalg::Matrix;
 //!
 //! let inputs = Matrix::new(2, 2, vec![-1.0, 2.0, 1.5, 3.0]);
 //!
 //! // Constructs a new `MinMaxScaler` to map minimum to 0 and maximum
 //! // to 1.
 //! let mut transformer = MinMaxFitter::default().fit(&amp;inputs).unwrap();
 //!
 //!
 //! // Transform the inputs to get output data with required minimum
 //! // and maximum.
 //! let transformed = transformer.transform(inputs).unwrap();
 //! ```

 </span><span class="kw">use </span>learning::error::{Error, ErrorKind};
 <span class="kw">use </span>learning::LearningResult;
 <span class="kw">use </span>linalg::{Matrix, BaseMatrix, BaseMatrixMut, Vector};
 <span class="kw">use super</span>::{Invertible, Transformer, TransformFitter};

 <span class="kw">use </span>rulinalg::utils;

 <span class="kw">use </span>libnum::Float;

 <span class="doccomment">/// A builder used to construct a `MinMaxScaler`
 </span><span class="attribute">#[derive(Debug)]
 </span><span class="kw">pub struct </span>MinMaxFitter&lt;T: Float&gt; {
     scaled_min: T,
     scaled_max: T
 }

 <span class="kw">impl</span>&lt;T: Float&gt; Default <span class="kw">for </span>MinMaxFitter&lt;T&gt; {
     <span class="kw">fn </span>default() -&gt; <span class="self">Self </span>{
         MinMaxFitter {
             scaled_min: T::zero(),
             scaled_max: T::one()
         }
     }
 }

 <span class="kw">impl</span>&lt;T: Float&gt; MinMaxFitter&lt;T&gt; {
     <span class="doccomment">/// Construct a new `MinMaxFitter` with
     /// specified mean and standard deviation.
     ///
     /// Note that this function does not create a `Transformer`
     /// only a builder which can be used to produce a fitted `Transformer`.
     ///
     /// # Examples
     ///
     /// ```
     /// use rusty_machine::data::transforms::MinMaxFitter;
     /// use rusty_machine::linalg::Matrix;
     ///
     /// let fitter = MinMaxFitter::new(0.0, 1.0);
     ///
     /// // We can call `fit` from the `transform::TransformFitter`
     /// // trait to create a `MinMaxScaler` used to actually transform data.
     /// use rusty_machine::data::transforms::TransformFitter;
     /// let mat = Matrix::new(2,2,vec![1.0, 2.0, 3.0, 5.0]);
     /// let transformer = fitter.fit(&amp;mat);
     /// ```
     </span><span class="kw">pub fn </span>new(min: T, max: T) -&gt; <span class="self">Self </span>{
         MinMaxFitter {
             scaled_min: min,
             scaled_max: max
         }
     }
 }

 <span class="kw">impl</span>&lt;T: Float&gt; TransformFitter&lt;Matrix&lt;T&gt;, MinMaxScaler&lt;T&gt;&gt; <span class="kw">for </span>MinMaxFitter&lt;T&gt; {
     <span class="kw">fn </span>fit(<span class="self">self</span>, inputs: <span class="kw-2">&amp;</span>Matrix&lt;T&gt;) -&gt; LearningResult&lt;MinMaxScaler&lt;T&gt;&gt; {
         <span class="kw">let </span>features = inputs.cols();

         <span class="comment">// TODO: can use min, max
         // https://github.com/AtheMathmo/rulinalg/pull/115
         </span><span class="kw">let </span><span class="kw-2">mut </span>input_min_max = <span class="macro">vec!</span>[(T::max_value(), T::min_value()); features];

         <span class="kw">for </span>row <span class="kw">in </span>inputs.row_iter() {
             <span class="kw">for </span>(idx, (feature, min_max)) <span class="kw">in </span>row.into_iter().zip(input_min_max.iter_mut()).enumerate() {
                 <span class="kw">if </span>!feature.is_finite() {
                     <span class="kw">return </span><span class="prelude-val">Err</span>(Error::new(ErrorKind::InvalidData,
                                           <span class="macro">format!</span>(<span class="string">&quot;Data point in column {} cannot be \
                                                    processed&quot;</span>,
                                                   idx)));
                 }
                 <span class="comment">// Update min
                 </span><span class="kw">if </span><span class="kw-2">*</span>feature &lt; min_max.<span class="number">0 </span>{
                     min_max.<span class="number">0 </span>= <span class="kw-2">*</span>feature;
                 }
                 <span class="comment">// Update max
                 </span><span class="kw">if </span><span class="kw-2">*</span>feature &gt; min_max.<span class="number">1 </span>{
                     min_max.<span class="number">1 </span>= <span class="kw-2">*</span>feature;
                 }
             }
         }

         <span class="comment">// We&#39;ll scale each feature by a * x + b.
         // Where scales holds `a` per column and consts
         // holds `b`.
         </span><span class="kw">let </span>scales = input_min_max.iter()
             .map(|<span class="kw-2">&amp;</span>(x, y)| {
                 <span class="kw">let </span>s = (<span class="self">self</span>.scaled_max - <span class="self">self</span>.scaled_min) / (y - x);
                 <span class="kw">if </span>s.is_finite() {
                     <span class="prelude-val">Ok</span>(s)
                 } <span class="kw">else </span>{
                     <span class="prelude-val">Err</span>(Error::new(ErrorKind::InvalidData,
                                    <span class="string">&quot;Constant feature columns not supported.&quot;</span>))
                 }
             })
             .collect::&lt;<span class="prelude-ty">Result</span>&lt;Vec&lt;<span class="kw">_</span>&gt;, <span class="kw">_</span>&gt;&gt;()<span class="question-mark">?</span>;

         <span class="kw">let </span>consts = input_min_max.iter()
             .zip(scales.iter())
             .map(|(<span class="kw-2">&amp;</span>(<span class="kw">_</span>, x), <span class="kw-2">&amp;</span>s)| <span class="self">self</span>.scaled_max - x * s)
             .collect::&lt;Vec&lt;<span class="kw">_</span>&gt;&gt;();

         <span class="prelude-val">Ok</span>(MinMaxScaler {
             scale_factors: Vector::new(scales),
             const_factors: Vector::new(consts)
         })
     }
 }

 <span class="doccomment">/// The `MinMaxScaler`
 ///
 /// The `MinMaxScaler` provides an implementation of `Transformer`
 /// which allows us to transform the input data to have a new minimum
 /// and maximum per column.
 ///
 /// See the module description for more information.
 </span><span class="attribute">#[derive(Debug)]
 </span><span class="kw">pub struct </span>MinMaxScaler&lt;T: Float&gt; {
     <span class="doccomment">/// Values to scale each column by
     </span>scale_factors: Vector&lt;T&gt;,
     <span class="doccomment">/// Values to add to each column after scaling
     </span>const_factors: Vector&lt;T&gt;,
 }


 <span class="kw">impl</span>&lt;T: Float&gt; Transformer&lt;Matrix&lt;T&gt;&gt; <span class="kw">for </span>MinMaxScaler&lt;T&gt; {
     <span class="kw">fn </span>transform(<span class="kw-2">&amp;mut </span><span class="self">self</span>, <span class="kw-2">mut </span>inputs: Matrix&lt;T&gt;) -&gt; <span class="prelude-ty">Result</span>&lt;Matrix&lt;T&gt;, Error&gt; {
         <span class="kw">if </span><span class="self">self</span>.scale_factors.size() != inputs.cols() {
             <span class="prelude-val">Err</span>(Error::new(ErrorKind::InvalidData,
                             <span class="string">&quot;Input data has different number of columns than fitted data.&quot;</span>))
         } <span class="kw">else </span>{
             <span class="kw">for </span><span class="kw-2">mut </span>row <span class="kw">in </span>inputs.row_iter_mut() {
                 utils::in_place_vec_bin_op(row.raw_slice_mut(), <span class="self">self</span>.scale_factors.data(), |x, <span class="kw-2">&amp;</span>y| {
                     <span class="kw-2">*</span>x = <span class="kw-2">*</span>x * y;
                 });

                 utils::in_place_vec_bin_op(row.raw_slice_mut(), <span class="self">self</span>.const_factors.data(), |x, <span class="kw-2">&amp;</span>y| {
                     <span class="kw-2">*</span>x = <span class="kw-2">*</span>x + y;
                 });
             }
             <span class="prelude-val">Ok</span>(inputs)
         }
     }
 }

 <span class="kw">impl</span>&lt;T: Float&gt; Invertible&lt;Matrix&lt;T&gt;&gt; <span class="kw">for </span>MinMaxScaler&lt;T&gt; {

     <span class="kw">fn </span>inv_transform(<span class="kw-2">&amp;</span><span class="self">self</span>, <span class="kw-2">mut </span>inputs: Matrix&lt;T&gt;) -&gt; <span class="prelude-ty">Result</span>&lt;Matrix&lt;T&gt;, Error&gt; {
         <span class="kw">let </span>features = <span class="self">self</span>.scale_factors.size();
         <span class="kw">if </span>inputs.cols() != features {
             <span class="kw">return </span><span class="prelude-val">Err</span>(Error::new(ErrorKind::InvalidData,
                                     <span class="string">&quot;Input data has different number of columns than fitted data.&quot;</span>));
         }

         <span class="kw">for </span><span class="kw-2">mut </span>row <span class="kw">in </span>inputs.row_iter_mut() {
             <span class="kw">for </span>i <span class="kw">in </span><span class="number">0</span>..features {
                 row[i] = (row[i] - <span class="self">self</span>.const_factors[i]) / <span class="self">self</span>.scale_factors[i];
             }
         }

         <span class="prelude-val">Ok</span>(inputs)
     }
 }

 <span class="attribute">#[cfg(test)]
 </span><span class="kw">mod </span>tests {
     <span class="kw">use super</span>::<span class="kw-2">*</span>;
     <span class="kw">use </span><span class="kw">super</span>::<span class="kw">super</span>::{Transformer, TransformFitter, Invertible};
     <span class="kw">use </span>linalg::Matrix;
     <span class="kw">use </span>std::f64;

     <span class="attribute">#[test]
     </span><span class="kw">fn </span>nan_data_test() {
         <span class="kw">let </span>inputs = Matrix::new(<span class="number">2</span>, <span class="number">2</span>, <span class="macro">vec!</span>[f64::NAN; <span class="number">4</span>]);

         <span class="kw">let </span>res = MinMaxFitter::new(<span class="number">0.0</span>, <span class="number">1.0</span>).fit(<span class="kw-2">&amp;</span>inputs);
         <span class="macro">assert!</span>(res.is_err());
     }

     <span class="attribute">#[test]
     </span><span class="kw">fn </span>infinity_data_test() {
         <span class="kw">let </span>inputs = Matrix::new(<span class="number">2</span>, <span class="number">2</span>, <span class="macro">vec!</span>[f64::INFINITY; <span class="number">4</span>]);

         <span class="kw">let </span>res = MinMaxFitter::new(<span class="number">0.0</span>, <span class="number">1.0</span>).fit(<span class="kw-2">&amp;</span>inputs);
         <span class="macro">assert!</span>(res.is_err());
     }

     <span class="attribute">#[test]
     </span><span class="kw">fn </span>basic_scale_test() {
         <span class="kw">let </span>inputs = Matrix::new(<span class="number">2</span>, <span class="number">2</span>, <span class="macro">vec!</span>[-<span class="number">1.0f32</span>, <span class="number">2.0</span>, <span class="number">0.0</span>, <span class="number">3.0</span>]);

         <span class="kw">let </span><span class="kw-2">mut </span>scaler = MinMaxFitter::new(<span class="number">0.0</span>, <span class="number">1.0</span>).fit(<span class="kw-2">&amp;</span>inputs).unwrap();
         <span class="kw">let </span>transformed = scaler.transform(inputs).unwrap();

         <span class="macro">assert!</span>(transformed.data().iter().all(|<span class="kw-2">&amp;</span>x| x &gt;= <span class="number">0.0</span>));
         <span class="macro">assert!</span>(transformed.data().iter().all(|<span class="kw-2">&amp;</span>x| x &lt;= <span class="number">1.0</span>));

         <span class="comment">// First row scales to 0 and second to 1
         </span>transformed[[<span class="number">0</span>, <span class="number">0</span>]].abs() &lt; <span class="number">1e-10</span>;
         transformed[[<span class="number">0</span>, <span class="number">1</span>]].abs() &lt; <span class="number">1e-10</span>;
         (transformed[[<span class="number">1</span>, <span class="number">0</span>]] - <span class="number">1.0</span>).abs() &lt; <span class="number">1e-10</span>;
         (transformed[[<span class="number">1</span>, <span class="number">1</span>]] - <span class="number">1.0</span>).abs() &lt; <span class="number">1e-10</span>;
     }

     <span class="attribute">#[test]
     </span><span class="kw">fn </span>custom_scale_test() {
         <span class="kw">let </span>inputs = Matrix::new(<span class="number">2</span>, <span class="number">2</span>, <span class="macro">vec!</span>[-<span class="number">1.0f32</span>, <span class="number">2.0</span>, <span class="number">0.0</span>, <span class="number">3.0</span>]);

         <span class="kw">let </span><span class="kw-2">mut </span>scaler = MinMaxFitter::new(<span class="number">1.0</span>, <span class="number">3.0</span>).fit(<span class="kw-2">&amp;</span>inputs).unwrap();
         <span class="kw">let </span>transformed = scaler.transform(inputs).unwrap();

         <span class="macro">assert!</span>(transformed.data().iter().all(|<span class="kw-2">&amp;</span>x| x &gt;= <span class="number">1.0</span>));
         <span class="macro">assert!</span>(transformed.data().iter().all(|<span class="kw-2">&amp;</span>x| x &lt;= <span class="number">3.0</span>));

         <span class="comment">// First row scales to 1 and second to 3
         </span>(transformed[[<span class="number">0</span>, <span class="number">0</span>]] - <span class="number">1.0</span>).abs() &lt; <span class="number">1e-10</span>;
         (transformed[[<span class="number">0</span>, <span class="number">1</span>]] - <span class="number">1.0</span>).abs() &lt; <span class="number">1e-10</span>;
         (transformed[[<span class="number">1</span>, <span class="number">0</span>]] - <span class="number">3.0</span>).abs() &lt; <span class="number">1e-10</span>;
         (transformed[[<span class="number">1</span>, <span class="number">1</span>]] - <span class="number">3.0</span>).abs() &lt; <span class="number">1e-10</span>;
     }

     <span class="attribute">#[test]
     </span><span class="kw">fn </span>constant_feature_test() {
         <span class="kw">let </span>inputs = Matrix::new(<span class="number">2</span>, <span class="number">2</span>, <span class="macro">vec!</span>[<span class="number">1.0</span>, <span class="number">2.0</span>, <span class="number">1.0</span>, <span class="number">3.0</span>]);

         <span class="kw">let </span>res = MinMaxFitter::new(<span class="number">0.0</span>, <span class="number">1.0</span>).fit(<span class="kw-2">&amp;</span>inputs);
         <span class="macro">assert!</span>(res.is_err());
     }

     <span class="attribute">#[test]
     </span><span class="kw">fn </span>inv_transform_identity_test() {
         <span class="kw">let </span>inputs = Matrix::new(<span class="number">2</span>, <span class="number">2</span>, <span class="macro">vec!</span>[-<span class="number">1.0f32</span>, <span class="number">2.0</span>, <span class="number">0.0</span>, <span class="number">3.0</span>]);

         <span class="kw">let </span><span class="kw-2">mut </span>scaler = MinMaxFitter::new(<span class="number">1.0</span>, <span class="number">3.0</span>).fit(<span class="kw-2">&amp;</span>inputs).unwrap();
         <span class="kw">let </span>transformed = scaler.transform(inputs.clone()).unwrap();

         <span class="kw">let </span>original = scaler.inv_transform(transformed).unwrap();

         <span class="macro">assert!</span>((inputs - original).data().iter().all(|x| x.abs() &lt; <span class="number">1e-5</span>));
     }
 }
 </code></pre></div>
 </section></div></main><div id="rustdoc-vars" data-root-path="../../../../" data-current-crate="rusty_machine" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html>