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| </pre><pre class="rust"><code><span class="comment">// Copyright 2021 Developers of the Rand project.</span> |
| <span class="comment">//</span> |
| <span class="comment">// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span> |
| <span class="comment">// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span> |
| <span class="comment">// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your</span> |
| <span class="comment">// option. This file may not be copied, modified, or distributed</span> |
| <span class="comment">// except according to those terms.</span> |
| |
| <span class="doccomment">//! The Zeta and related distributions.</span> |
| |
| <span class="kw">use</span> <span class="ident">num_traits::Float</span>; |
| <span class="kw">use</span> <span class="kw">crate</span>::{<span class="ident">Distribution</span>, <span class="ident">Standard</span>}; |
| <span class="kw">use</span> <span class="ident">rand</span>::{<span class="ident">Rng</span>, <span class="ident">distributions::OpenClosed01</span>}; |
| <span class="kw">use</span> <span class="ident">core::fmt</span>; |
| |
| <span class="doccomment">/// Samples integers according to the [zeta distribution].</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// The zeta distribution is a limit of the [`Zipf`] distribution. Sometimes it</span> |
| <span class="doccomment">/// is called one of the following: discrete Pareto, Riemann-Zeta, Zipf, or</span> |
| <span class="doccomment">/// Zipf–Estoup distribution.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// It has the density function `f(k) = k^(-a) / C(a)` for `k >= 1`, where `a`</span> |
| <span class="doccomment">/// is the parameter and `C(a)` is the Riemann zeta function.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Example</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">/// use rand::prelude::*;</span> |
| <span class="doccomment">/// use rand_distr::Zeta;</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// let val: f64 = thread_rng().sample(Zeta::new(1.5).unwrap());</span> |
| <span class="doccomment">/// println!("{}", val);</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Remarks</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// The zeta distribution has no upper limit. Sampled values may be infinite.</span> |
| <span class="doccomment">/// In particular, a value of infinity might be returned for the following</span> |
| <span class="doccomment">/// reasons:</span> |
| <span class="doccomment">/// 1. it is the best representation in the type `F` of the actual sample.</span> |
| <span class="doccomment">/// 2. to prevent infinite loops for very small `a`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Implementation details</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// We are using the algorithm from [Non-Uniform Random Variate Generation],</span> |
| <span class="doccomment">/// Section 6.1, page 551.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// [zeta distribution]: https://en.wikipedia.org/wiki/Zeta_distribution</span> |
| <span class="doccomment">/// [Non-Uniform Random Variate Generation]: https://doi.org/10.1007/978-1-4613-8643-8</span> |
| <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Debug</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Zeta</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> |
| <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">Float</span>, <span class="ident">Standard</span>: <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span>, <span class="ident">OpenClosed01</span>: <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> |
| { |
| <span class="ident">a_minus_1</span>: <span class="ident">F</span>, |
| <span class="ident">b</span>: <span class="ident">F</span>, |
| } |
| |
| <span class="doccomment">/// Error type returned from `Zeta::new`.</span> |
| <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Debug</span>, <span class="ident">PartialEq</span>, <span class="ident">Eq</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">ZetaError</span> { |
| <span class="doccomment">/// `a <= 1` or `nan`.</span> |
| <span class="ident">ATooSmall</span>, |
| } |
| |
| <span class="kw">impl</span> <span class="ident">fmt::Display</span> <span class="kw">for</span> <span class="ident">ZetaError</span> { |
| <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&mut</span> <span class="ident">fmt::Formatter</span><span class="op"><</span><span class="lifetime">'_</span><span class="op">></span>) -> <span class="ident">fmt::Result</span> { |
| <span class="ident">f</span>.<span class="ident">write_str</span>(<span class="kw">match</span> <span class="self">self</span> { |
| <span class="ident">ZetaError::ATooSmall</span> => <span class="string">"a <= 1 or is NaN in Zeta distribution"</span>, |
| }) |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)))]</span> |
| <span class="kw">impl</span> <span class="ident">std::error::Error</span> <span class="kw">for</span> <span class="ident">ZetaError</span> {} |
| |
| <span class="kw">impl</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> <span class="ident">Zeta</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> |
| <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">Float</span>, <span class="ident">Standard</span>: <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span>, <span class="ident">OpenClosed01</span>: <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> |
| { |
| <span class="doccomment">/// Construct a new `Zeta` distribution with given `a` parameter.</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">a</span>: <span class="ident">F</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Zeta</span><span class="op"><</span><span class="ident">F</span><span class="op">></span>, <span class="ident">ZetaError</span><span class="op">></span> { |
| <span class="kw">if</span> <span class="op">!</span>(<span class="ident">a</span> <span class="op">></span> <span class="ident">F::one</span>()) { |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">ZetaError::ATooSmall</span>); |
| } |
| <span class="kw">let</span> <span class="ident">a_minus_1</span> <span class="op">=</span> <span class="ident">a</span> <span class="op">-</span> <span class="ident">F::one</span>(); |
| <span class="kw">let</span> <span class="ident">two</span> <span class="op">=</span> <span class="ident">F::one</span>() <span class="op">+</span> <span class="ident">F::one</span>(); |
| <span class="prelude-val">Ok</span>(<span class="ident">Zeta</span> { |
| <span class="ident">a_minus_1</span>, |
| <span class="ident">b</span>: <span class="ident">two</span>.<span class="ident">powf</span>(<span class="ident">a_minus_1</span>), |
| }) |
| } |
| } |
| |
| <span class="kw">impl</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Zeta</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> |
| <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">Float</span>, <span class="ident">Standard</span>: <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span>, <span class="ident">OpenClosed01</span>: <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> |
| { |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">sample</span><span class="op"><</span><span class="ident">R</span>: <span class="ident">Rng</span> <span class="op">+</span> <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">rng</span>: <span class="kw-2">&mut</span> <span class="ident">R</span>) -> <span class="ident">F</span> { |
| <span class="kw">loop</span> { |
| <span class="kw">let</span> <span class="ident">u</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">sample</span>(<span class="ident">OpenClosed01</span>); |
| <span class="kw">let</span> <span class="ident">x</span> <span class="op">=</span> <span class="ident">u</span>.<span class="ident">powf</span>(<span class="op">-</span><span class="ident">F::one</span>() <span class="op">/</span> <span class="self">self</span>.<span class="ident">a_minus_1</span>).<span class="ident">floor</span>(); |
| <span class="macro">debug_assert!</span>(<span class="ident">x</span> <span class="op">></span><span class="op">=</span> <span class="ident">F::one</span>()); |
| <span class="kw">if</span> <span class="ident">x</span>.<span class="ident">is_infinite</span>() { |
| <span class="comment">// For sufficiently small `a`, `x` will always be infinite,</span> |
| <span class="comment">// which is rejected, resulting in an infinite loop. We avoid</span> |
| <span class="comment">// this by always returning infinity instead.</span> |
| <span class="kw">return</span> <span class="ident">x</span>; |
| } |
| |
| <span class="kw">let</span> <span class="ident">t</span> <span class="op">=</span> (<span class="ident">F::one</span>() <span class="op">+</span> <span class="ident">F::one</span>() <span class="op">/</span> <span class="ident">x</span>).<span class="ident">powf</span>(<span class="self">self</span>.<span class="ident">a_minus_1</span>); |
| |
| <span class="kw">let</span> <span class="ident">v</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">sample</span>(<span class="ident">Standard</span>); |
| <span class="kw">if</span> <span class="ident">v</span> <span class="op">*</span> <span class="ident">x</span> <span class="op">*</span> (<span class="ident">t</span> <span class="op">-</span> <span class="ident">F::one</span>()) <span class="op">*</span> <span class="self">self</span>.<span class="ident">b</span> <span class="op"><</span><span class="op">=</span> <span class="ident">t</span> <span class="op">*</span> (<span class="self">self</span>.<span class="ident">b</span> <span class="op">-</span> <span class="ident">F::one</span>()) { |
| <span class="kw">return</span> <span class="ident">x</span>; |
| } |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Samples integers according to the Zipf distribution.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// The samples follow Zipf's law: The frequency of each sample from a finite</span> |
| <span class="doccomment">/// set of size `n` is inversely proportional to a power of its frequency rank</span> |
| <span class="doccomment">/// (with exponent `s`).</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// For large `n`, this converges to the [`Zeta`] distribution.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// For `s = 0`, this becomes a uniform distribution.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Example</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">/// use rand::prelude::*;</span> |
| <span class="doccomment">/// use rand_distr::Zipf;</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// let val: f64 = thread_rng().sample(Zipf::new(10, 1.5).unwrap());</span> |
| <span class="doccomment">/// println!("{}", val);</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Implementation details</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Implemented via [rejection sampling](https://en.wikipedia.org/wiki/Rejection_sampling),</span> |
| <span class="doccomment">/// due to Jason Crease[1].</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// [1]: https://jasoncrease.medium.com/rejection-sampling-the-zipf-distribution-6b359792cffa</span> |
| <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Debug</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Zipf</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> |
| <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">Float</span>, <span class="ident">Standard</span>: <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> { |
| <span class="ident">n</span>: <span class="ident">F</span>, |
| <span class="ident">s</span>: <span class="ident">F</span>, |
| <span class="ident">t</span>: <span class="ident">F</span>, |
| <span class="ident">q</span>: <span class="ident">F</span>, |
| } |
| |
| <span class="doccomment">/// Error type returned from `Zipf::new`.</span> |
| <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Debug</span>, <span class="ident">PartialEq</span>, <span class="ident">Eq</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">ZipfError</span> { |
| <span class="doccomment">/// `s < 0` or `nan`.</span> |
| <span class="ident">STooSmall</span>, |
| <span class="doccomment">/// `n < 1`.</span> |
| <span class="ident">NTooSmall</span>, |
| } |
| |
| <span class="kw">impl</span> <span class="ident">fmt::Display</span> <span class="kw">for</span> <span class="ident">ZipfError</span> { |
| <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&mut</span> <span class="ident">fmt::Formatter</span><span class="op"><</span><span class="lifetime">'_</span><span class="op">></span>) -> <span class="ident">fmt::Result</span> { |
| <span class="ident">f</span>.<span class="ident">write_str</span>(<span class="kw">match</span> <span class="self">self</span> { |
| <span class="ident">ZipfError::STooSmall</span> => <span class="string">"s < 0 or is NaN in Zipf distribution"</span>, |
| <span class="ident">ZipfError::NTooSmall</span> => <span class="string">"n < 1 in Zipf distribution"</span>, |
| }) |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">doc_cfg</span>, <span class="ident">doc</span>(<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)))]</span> |
| <span class="kw">impl</span> <span class="ident">std::error::Error</span> <span class="kw">for</span> <span class="ident">ZipfError</span> {} |
| |
| <span class="kw">impl</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> <span class="ident">Zipf</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> |
| <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">Float</span>, <span class="ident">Standard</span>: <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> { |
| <span class="doccomment">/// Construct a new `Zipf` distribution for a set with `n` elements and a</span> |
| <span class="doccomment">/// frequency rank exponent `s`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// For large `n`, rounding may occur to fit the number into the float type.</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">n</span>: <span class="ident">u64</span>, <span class="ident">s</span>: <span class="ident">F</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Zipf</span><span class="op"><</span><span class="ident">F</span><span class="op">></span>, <span class="ident">ZipfError</span><span class="op">></span> { |
| <span class="kw">if</span> <span class="op">!</span>(<span class="ident">s</span> <span class="op">></span><span class="op">=</span> <span class="ident">F::zero</span>()) { |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">ZipfError::STooSmall</span>); |
| } |
| <span class="kw">if</span> <span class="ident">n</span> <span class="op"><</span> <span class="number">1</span> { |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">ZipfError::NTooSmall</span>); |
| } |
| <span class="kw">let</span> <span class="ident">n</span> <span class="op">=</span> <span class="ident">F::from</span>(<span class="ident">n</span>).<span class="ident">unwrap</span>(); <span class="comment">// This does not fail.</span> |
| <span class="kw">let</span> <span class="ident">q</span> <span class="op">=</span> <span class="kw">if</span> <span class="ident">s</span> <span class="op">!</span><span class="op">=</span> <span class="ident">F::one</span>() { |
| <span class="comment">// Make sure to calculate the division only once.</span> |
| <span class="ident">F::one</span>() <span class="op">/</span> (<span class="ident">F::one</span>() <span class="op">-</span> <span class="ident">s</span>) |
| } <span class="kw">else</span> { |
| <span class="comment">// This value is never used.</span> |
| <span class="ident">F::zero</span>() |
| }; |
| <span class="kw">let</span> <span class="ident">t</span> <span class="op">=</span> <span class="kw">if</span> <span class="ident">s</span> <span class="op">!</span><span class="op">=</span> <span class="ident">F::one</span>() { |
| (<span class="ident">n</span>.<span class="ident">powf</span>(<span class="ident">F::one</span>() <span class="op">-</span> <span class="ident">s</span>) <span class="op">-</span> <span class="ident">s</span>) <span class="op">*</span> <span class="ident">q</span> |
| } <span class="kw">else</span> { |
| <span class="ident">F::one</span>() <span class="op">+</span> <span class="ident">n</span>.<span class="ident">ln</span>() |
| }; |
| <span class="macro">debug_assert!</span>(<span class="ident">t</span> <span class="op">></span> <span class="ident">F::zero</span>()); |
| <span class="prelude-val">Ok</span>(<span class="ident">Zipf</span> { |
| <span class="ident">n</span>, <span class="ident">s</span>, <span class="ident">t</span>, <span class="ident">q</span> |
| }) |
| } |
| |
| <span class="doccomment">/// Inverse cumulative density function</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">inv_cdf</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">p</span>: <span class="ident">F</span>) -> <span class="ident">F</span> { |
| <span class="kw">let</span> <span class="ident">one</span> <span class="op">=</span> <span class="ident">F::one</span>(); |
| <span class="kw">let</span> <span class="ident">pt</span> <span class="op">=</span> <span class="ident">p</span> <span class="op">*</span> <span class="self">self</span>.<span class="ident">t</span>; |
| <span class="kw">if</span> <span class="ident">pt</span> <span class="op"><</span><span class="op">=</span> <span class="ident">one</span> { |
| <span class="ident">pt</span> |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="self">self</span>.<span class="ident">s</span> <span class="op">!</span><span class="op">=</span> <span class="ident">one</span> { |
| (<span class="ident">pt</span> <span class="op">*</span> (<span class="ident">one</span> <span class="op">-</span> <span class="self">self</span>.<span class="ident">s</span>) <span class="op">+</span> <span class="self">self</span>.<span class="ident">s</span>).<span class="ident">powf</span>(<span class="self">self</span>.<span class="ident">q</span>) |
| } <span class="kw">else</span> { |
| (<span class="ident">pt</span> <span class="op">-</span> <span class="ident">one</span>).<span class="ident">exp</span>() |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Zipf</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> |
| <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">Float</span>, <span class="ident">Standard</span>: <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> |
| { |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">fn</span> <span class="ident">sample</span><span class="op"><</span><span class="ident">R</span>: <span class="ident">Rng</span> <span class="op">+</span> <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">rng</span>: <span class="kw-2">&mut</span> <span class="ident">R</span>) -> <span class="ident">F</span> { |
| <span class="kw">let</span> <span class="ident">one</span> <span class="op">=</span> <span class="ident">F::one</span>(); |
| <span class="kw">loop</span> { |
| <span class="kw">let</span> <span class="ident">inv_b</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inv_cdf</span>(<span class="ident">rng</span>.<span class="ident">sample</span>(<span class="ident">Standard</span>)); |
| <span class="kw">let</span> <span class="ident">x</span> <span class="op">=</span> (<span class="ident">inv_b</span> <span class="op">+</span> <span class="ident">one</span>).<span class="ident">floor</span>(); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">ratio</span> <span class="op">=</span> <span class="ident">x</span>.<span class="ident">powf</span>(<span class="op">-</span><span class="self">self</span>.<span class="ident">s</span>); |
| <span class="kw">if</span> <span class="ident">x</span> <span class="op">></span> <span class="ident">one</span> { |
| <span class="ident">ratio</span> <span class="op">=</span> <span class="ident">ratio</span> <span class="op">*</span> <span class="ident">inv_b</span>.<span class="ident">powf</span>(<span class="self">self</span>.<span class="ident">s</span>) |
| }; |
| |
| <span class="kw">let</span> <span class="ident">y</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">sample</span>(<span class="ident">Standard</span>); |
| <span class="kw">if</span> <span class="ident">y</span> <span class="op"><</span> <span class="ident">ratio</span> { |
| <span class="kw">return</span> <span class="ident">x</span>; |
| } |
| } |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span> |
| <span class="kw">mod</span> <span class="ident">tests</span> { |
| <span class="kw">use</span> <span class="kw">super</span>::<span class="kw-2">*</span>; |
| |
| <span class="kw">fn</span> <span class="ident">test_samples</span><span class="op"><</span><span class="ident">F</span>: <span class="ident">Float</span> <span class="op">+</span> <span class="ident">core::fmt::Debug</span>, <span class="ident">D</span>: <span class="ident">Distribution</span><span class="op"><</span><span class="ident">F</span><span class="op">></span><span class="op">></span>( |
| <span class="ident">distr</span>: <span class="ident">D</span>, <span class="ident">zero</span>: <span class="ident">F</span>, <span class="ident">expected</span>: <span class="kw-2">&</span>[<span class="ident">F</span>], |
| ) { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">213</span>); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> [<span class="ident">zero</span>; <span class="number">4</span>]; |
| <span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="kw-2">&mut</span> <span class="ident">buf</span> { |
| <span class="kw-2">*</span><span class="ident">x</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">sample</span>(<span class="kw-2">&</span><span class="ident">distr</span>); |
| } |
| <span class="macro">assert_eq!</span>(<span class="ident">buf</span>, <span class="ident">expected</span>); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="attribute">#[<span class="ident">should_panic</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zeta_invalid</span>() { |
| <span class="ident">Zeta::new</span>(<span class="number">1.</span>).<span class="ident">unwrap</span>(); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="attribute">#[<span class="ident">should_panic</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zeta_nan</span>() { |
| <span class="ident">Zeta::new</span>(<span class="ident">core::f64::NAN</span>).<span class="ident">unwrap</span>(); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zeta_sample</span>() { |
| <span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="number">2.0</span>; |
| <span class="kw">let</span> <span class="ident">d</span> <span class="op">=</span> <span class="ident">Zeta::new</span>(<span class="ident">a</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">1</span>); |
| <span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">1000</span> { |
| <span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="ident">d</span>.<span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">rng</span>); |
| <span class="macro">assert!</span>(<span class="ident">r</span> <span class="op">></span><span class="op">=</span> <span class="number">1.</span>); |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zeta_small_a</span>() { |
| <span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="number">1.</span> <span class="op">+</span> <span class="number">1e-15</span>; |
| <span class="kw">let</span> <span class="ident">d</span> <span class="op">=</span> <span class="ident">Zeta::new</span>(<span class="ident">a</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">2</span>); |
| <span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">1000</span> { |
| <span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="ident">d</span>.<span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">rng</span>); |
| <span class="macro">assert!</span>(<span class="ident">r</span> <span class="op">></span><span class="op">=</span> <span class="number">1.</span>); |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zeta_value_stability</span>() { |
| <span class="ident">test_samples</span>(<span class="ident">Zeta::new</span>(<span class="number">1.5</span>).<span class="ident">unwrap</span>(), <span class="number">0f32</span>, <span class="kw-2">&</span>[ |
| <span class="number">1.0</span>, <span class="number">2.0</span>, <span class="number">1.0</span>, <span class="number">1.0</span>, |
| ]); |
| <span class="ident">test_samples</span>(<span class="ident">Zeta::new</span>(<span class="number">2.0</span>).<span class="ident">unwrap</span>(), <span class="number">0f64</span>, <span class="kw-2">&</span>[ |
| <span class="number">2.0</span>, <span class="number">1.0</span>, <span class="number">1.0</span>, <span class="number">1.0</span>, |
| ]); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="attribute">#[<span class="ident">should_panic</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zipf_s_too_small</span>() { |
| <span class="ident">Zipf::new</span>(<span class="number">10</span>, <span class="op">-</span><span class="number">1.</span>).<span class="ident">unwrap</span>(); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="attribute">#[<span class="ident">should_panic</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zipf_n_too_small</span>() { |
| <span class="ident">Zipf::new</span>(<span class="number">0</span>, <span class="number">1.</span>).<span class="ident">unwrap</span>(); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="attribute">#[<span class="ident">should_panic</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zipf_nan</span>() { |
| <span class="ident">Zipf::new</span>(<span class="number">10</span>, <span class="ident">core::f64::NAN</span>).<span class="ident">unwrap</span>(); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zipf_sample</span>() { |
| <span class="kw">let</span> <span class="ident">d</span> <span class="op">=</span> <span class="ident">Zipf::new</span>(<span class="number">10</span>, <span class="number">0.5</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">2</span>); |
| <span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">1000</span> { |
| <span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="ident">d</span>.<span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">rng</span>); |
| <span class="macro">assert!</span>(<span class="ident">r</span> <span class="op">></span><span class="op">=</span> <span class="number">1.</span>); |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zipf_sample_s_1</span>() { |
| <span class="kw">let</span> <span class="ident">d</span> <span class="op">=</span> <span class="ident">Zipf::new</span>(<span class="number">10</span>, <span class="number">1.</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">2</span>); |
| <span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">1000</span> { |
| <span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="ident">d</span>.<span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">rng</span>); |
| <span class="macro">assert!</span>(<span class="ident">r</span> <span class="op">></span><span class="op">=</span> <span class="number">1.</span>); |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zipf_sample_s_0</span>() { |
| <span class="kw">let</span> <span class="ident">d</span> <span class="op">=</span> <span class="ident">Zipf::new</span>(<span class="number">10</span>, <span class="number">0.</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">2</span>); |
| <span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">1000</span> { |
| <span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="ident">d</span>.<span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">rng</span>); |
| <span class="macro">assert!</span>(<span class="ident">r</span> <span class="op">></span><span class="op">=</span> <span class="number">1.</span>); |
| } |
| <span class="comment">// TODO: verify that this is a uniform distribution</span> |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zipf_sample_large_n</span>() { |
| <span class="kw">let</span> <span class="ident">d</span> <span class="op">=</span> <span class="ident">Zipf::new</span>(<span class="ident">core::u64::MAX</span>, <span class="number">1.5</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">2</span>); |
| <span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">1000</span> { |
| <span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="ident">d</span>.<span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">rng</span>); |
| <span class="macro">assert!</span>(<span class="ident">r</span> <span class="op">></span><span class="op">=</span> <span class="number">1.</span>); |
| } |
| <span class="comment">// TODO: verify that this is a zeta distribution</span> |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">zipf_value_stability</span>() { |
| <span class="ident">test_samples</span>(<span class="ident">Zipf::new</span>(<span class="number">10</span>, <span class="number">0.5</span>).<span class="ident">unwrap</span>(), <span class="number">0f32</span>, <span class="kw-2">&</span>[ |
| <span class="number">10.0</span>, <span class="number">2.0</span>, <span class="number">6.0</span>, <span class="number">7.0</span> |
| ]); |
| <span class="ident">test_samples</span>(<span class="ident">Zipf::new</span>(<span class="number">10</span>, <span class="number">2.0</span>).<span class="ident">unwrap</span>(), <span class="number">0f64</span>, <span class="kw-2">&</span>[ |
| <span class="number">1.0</span>, <span class="number">2.0</span>, <span class="number">3.0</span>, <span class="number">2.0</span> |
| ]); |
| } |
| } |
| </code></pre></div> |
| </section><section id="search" class="content hidden"></section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="rand_distr" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.60.0-nightly (1bd4fdc94 2022-01-12)" ></div> |
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