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<p class='location'>Crate num</p><div class="block items"><ul><li><a href="#modules">Modules</a></li><li><a href="#traits">Traits</a></li><li><a href="#functions">Functions</a></li></ul></div><p class='location'></p><script>window.sidebarCurrent = {name: 'num', ty: 'mod', relpath: '../'};</script>
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<h1 class='fqn'><span class='in-band'>Crate <a class="mod" href=''>num</a></span><span class='out-of-band'><span id='render-detail'>
<a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">
[<span class='inner'>−</span>]
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</span><a class='srclink' href='../src/num/lib.rs.html#11-111' title='goto source code'>[src]</a></span></h1>
<div class='docblock'><p>A collection of numeric types and traits for Rust.</p>
<p>This includes new types for big integers, rationals, and complex numbers,
new traits for generic programming on numeric properties like <code>Integer</code>,
and generic range iterators.</p>
<h2 id='example' class='section-header'><a href='#example'>Example</a></h2>
<p>This example uses the BigRational type and <a href="https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method">Newton's method</a> to
approximate a square root to arbitrary precision:</p>
<pre class="rust rust-example-rendered">
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">num</span>;
<span class="kw">use</span> <span class="ident">num</span>::<span class="ident">FromPrimitive</span>;
<span class="kw">use</span> <span class="ident">num</span>::<span class="ident">bigint</span>::<span class="ident">BigInt</span>;
<span class="kw">use</span> <span class="ident">num</span>::<span class="ident">rational</span>::{<span class="ident">Ratio</span>, <span class="ident">BigRational</span>};
<span class="kw">fn</span> <span class="ident">approx_sqrt</span>(<span class="ident">number</span>: <span class="ident">u64</span>, <span class="ident">iterations</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">BigRational</span> {
<span class="kw">let</span> <span class="ident">start</span>: <span class="ident">Ratio</span><span class="op"><</span><span class="ident">BigInt</span><span class="op">></span> <span class="op">=</span> <span class="ident">Ratio</span>::<span class="ident">from_integer</span>(<span class="ident">FromPrimitive</span>::<span class="ident">from_u64</span>(<span class="ident">number</span>).<span class="ident">unwrap</span>());
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">approx</span> <span class="op">=</span> <span class="ident">start</span>.<span class="ident">clone</span>();
<span class="kw">for</span> _ <span class="kw">in</span> <span class="number">0</span>..<span class="ident">iterations</span> {
<span class="ident">approx</span> <span class="op">=</span> (<span class="kw-2">&</span><span class="ident">approx</span> <span class="op">+</span> (<span class="kw-2">&</span><span class="ident">start</span> <span class="op">/</span> <span class="kw-2">&</span><span class="ident">approx</span>)) <span class="op">/</span>
<span class="ident">Ratio</span>::<span class="ident">from_integer</span>(<span class="ident">FromPrimitive</span>::<span class="ident">from_u64</span>(<span class="number">2</span>).<span class="ident">unwrap</span>());
}
<span class="ident">approx</span>
}
<span class="kw">fn</span> <span class="ident">main</span>() {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{}"</span>, <span class="ident">approx_sqrt</span>(<span class="number">10</span>, <span class="number">4</span>)); <span class="comment">// prints 4057691201/1283082416</span>
}
<a class="test-arrow" target="_blank" href="http://play.integer32.com/?code=extern%20crate%20num%3B%0A%23%5Bcfg(all(feature%20%3D%20%22bigint%22%2C%20feature%3D%22rational%22))%5D%0Amod%20test%20%7B%0A%0Ause%20num%3A%3AFromPrimitive%3B%0Ause%20num%3A%3Abigint%3A%3ABigInt%3B%0Ause%20num%3A%3Arational%3A%3A%7BRatio%2C%20BigRational%7D%3B%0A%0Apub%0Afn%20approx_sqrt(number%3A%20u64%2C%20iterations%3A%20usize)%20-%3E%20BigRational%20%7B%0A%20%20%20%20let%20start%3A%20Ratio%3CBigInt%3E%20%3D%20Ratio%3A%3Afrom_integer(FromPrimitive%3A%3Afrom_u64(number).unwrap())%3B%0A%20%20%20%20let%20mut%20approx%20%3D%20start.clone()%3B%0A%0A%20%20%20%20for%20_%20in%200..iterations%20%7B%0A%20%20%20%20%20%20%20%20approx%20%3D%20(%26approx%20%2B%20(%26start%20%2F%20%26approx))%20%2F%0A%20%20%20%20%20%20%20%20%20%20%20%20Ratio%3A%3Afrom_integer(FromPrimitive%3A%3Afrom_u64(2).unwrap())%3B%0A%20%20%20%20%7D%0A%0A%20%20%20%20approx%0A%7D%0A%7D%0A%23%5Bcfg(not(all(feature%20%3D%20%22bigint%22%2C%20feature%3D%22rational%22)))%5D%0Amod%20test%20%7B%20pub%20fn%20approx_sqrt(n%3A%20u64%2C%20_%3A%20usize)%20-%3E%20u64%20%7B%20n%20%7D%20%7D%0Ause%20test%3A%3Aapprox_sqrt%3B%0A%0Afn%20main()%20%7B%0A%20%20%20%20println!(%22%7B%7D%22%2C%20approx_sqrt(10%2C%204))%3B%20%2F%2F%20prints%204057691201%2F1283082416%0A%7D%0A">Run</a></pre>
</div><h2 id='modules' class='section-header'><a href="#modules">Modules</a></h2>
<table>
<tr class=' module-item'>
<td><a class="mod" href="cast/index.html"
title='mod num::cast'>cast</a></td>
<td class='docblock-short'>
</td>
</tr>
<tr class=' module-item'>
<td><a class="mod" href="integer/index.html"
title='mod num::integer'>integer</a></td>
<td class='docblock-short'>
</td>
</tr>
<tr class=' module-item'>
<td><a class="mod" href="iter/index.html"
title='mod num::iter'>iter</a></td>
<td class='docblock-short'>
</td>
</tr>
<tr class=' module-item'>
<td><a class="mod" href="pow/index.html"
title='mod num::pow'>pow</a></td>
<td class='docblock-short'>
</td>
</tr>
<tr class=' module-item'>
<td><a class="mod" href="traits/index.html"
title='mod num::traits'>traits</a></td>
<td class='docblock-short'>
</td>
</tr></table><h2 id='traits' class='section-header'><a href="#traits">Traits</a></h2>
<table>
<tr class=' module-item'>
<td><a class="trait" href="trait.Bounded.html"
title='trait num::Bounded'>Bounded</a></td>
<td class='docblock-short'>
<p>Numbers which have upper and lower bounds</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.CheckedAdd.html"
title='trait num::CheckedAdd'>CheckedAdd</a></td>
<td class='docblock-short'>
<p>Performs addition that returns <code>None</code> instead of wrapping around on
overflow.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.CheckedDiv.html"
title='trait num::CheckedDiv'>CheckedDiv</a></td>
<td class='docblock-short'>
<p>Performs division that returns <code>None</code> instead of panicking on division by zero and instead of
wrapping around on underflow and overflow.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.CheckedMul.html"
title='trait num::CheckedMul'>CheckedMul</a></td>
<td class='docblock-short'>
<p>Performs multiplication that returns <code>None</code> instead of wrapping around on underflow or
overflow.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.CheckedSub.html"
title='trait num::CheckedSub'>CheckedSub</a></td>
<td class='docblock-short'>
<p>Performs subtraction that returns <code>None</code> instead of wrapping around on underflow.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.Float.html"
title='trait num::Float'>Float</a></td>
<td class='docblock-short'>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.FromPrimitive.html"
title='trait num::FromPrimitive'>FromPrimitive</a></td>
<td class='docblock-short'>
<p>A generic trait for converting a number to a value.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.Integer.html"
title='trait num::Integer'>Integer</a></td>
<td class='docblock-short'>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.Num.html"
title='trait num::Num'>Num</a></td>
<td class='docblock-short'>
<p>The base trait for numeric types, covering <code>0</code> and <code>1</code> values,
comparisons, basic numeric operations, and string conversion.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.NumCast.html"
title='trait num::NumCast'>NumCast</a></td>
<td class='docblock-short'>
<p>An interface for casting between machine scalars.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.One.html"
title='trait num::One'>One</a></td>
<td class='docblock-short'>
<p>Defines a multiplicative identity element for <code>Self</code>.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.PrimInt.html"
title='trait num::PrimInt'>PrimInt</a></td>
<td class='docblock-short'>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.Saturating.html"
title='trait num::Saturating'>Saturating</a></td>
<td class='docblock-short'>
<p>Saturating math operations</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.Signed.html"
title='trait num::Signed'>Signed</a></td>
<td class='docblock-short'>
<p>Useful functions for signed numbers (i.e. numbers that can be negative).</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.ToPrimitive.html"
title='trait num::ToPrimitive'>ToPrimitive</a></td>
<td class='docblock-short'>
<p>A generic trait for converting a value to a number.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.Unsigned.html"
title='trait num::Unsigned'>Unsigned</a></td>
<td class='docblock-short'>
<p>A trait for values which cannot be negative</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.Zero.html"
title='trait num::Zero'>Zero</a></td>
<td class='docblock-short'>
<p>Defines an additive identity element for <code>Self</code>.</p>
</td>
</tr></table><h2 id='functions' class='section-header'><a href="#functions">Functions</a></h2>
<table>
<tr class=' module-item'>
<td><a class="fn" href="fn.abs.html"
title='fn num::abs'>abs</a></td>
<td class='docblock-short'>
<p>Computes the absolute value.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.abs_sub.html"
title='fn num::abs_sub'>abs_sub</a></td>
<td class='docblock-short'>
<p>The positive difference of two numbers.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.checked_pow.html"
title='fn num::checked_pow'>checked_pow</a></td>
<td class='docblock-short'>
<p>Raises a value to the power of exp, returning <code>None</code> if an overflow occurred.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.clamp.html"
title='fn num::clamp'>clamp</a></td>
<td class='docblock-short'>
<p>A value bounded by a minimum and a maximum</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.one.html"
title='fn num::one'>one</a></td>
<td class='docblock-short'>
<p>Returns the multiplicative identity, <code>1</code>.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.range.html"
title='fn num::range'>range</a></td>
<td class='docblock-short'>
<p>Returns an iterator over the given range [start, stop) (that is, starting
at start (inclusive), and ending at stop (exclusive)).</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.range_inclusive.html"
title='fn num::range_inclusive'>range_inclusive</a></td>
<td class='docblock-short'>
<p>Return an iterator over the range [start, stop]</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.range_step.html"
title='fn num::range_step'>range_step</a></td>
<td class='docblock-short'>
<p>Return an iterator over the range [start, stop) by <code>step</code>. It handles overflow by stopping.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.range_step_inclusive.html"
title='fn num::range_step_inclusive'>range_step_inclusive</a></td>
<td class='docblock-short'>
<p>Return an iterator over the range [start, stop] by <code>step</code>. It handles overflow by stopping.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.signum.html"
title='fn num::signum'>signum</a></td>
<td class='docblock-short'>
<p>Returns the sign of the number.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="fn" href="fn.zero.html"
title='fn num::zero'>zero</a></td>
<td class='docblock-short'>
<p>Returns the additive identity, <code>0</code>.</p>
</td>
</tr></table></section>
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