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 <div class="chapter">
 <div class="titlepage"><div>
 <div><h2 class="title">
 <a name="boost_units"></a>Chapter&#160;26.&#160;Boost.Units 1.1.0</h2></div>
 <div><div class="author"><h3 class="author">
 <span class="firstname">Matthias C.</span> <span class="surname">Schabel</span>
 </h3></div></div>
 <div><div class="author"><h3 class="author">
 <span class="firstname">Steven</span> <span class="surname">Watanabe</span>
 </h3></div></div>
 <div><p class="copyright">Copyright &#169; 2003 -2008 Matthias Christian Schabel, 2007-2010 Steven
       Watanabe</p></div>
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 <a name="id2768850"></a><p>
         Distributed under the Boost Software License, Version 1.0. (See accompanying
         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
       </p>
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 <div class="toc">
 <p><b>Table of Contents</b></p>
 <dl>
 <dt><span class="section"><a href="boost_units.html#boost_units.Introduction">Introduction</a></span></dt>
 <dt><span class="section"><a href="boost_units/Quick_Start.html">Quick Start</a></span></dt>
 <dt><span class="section"><a href="boost_units/Dimensional_Analysis.html">Dimensional Analysis</a></span></dt>
 <dt><span class="section"><a href="boost_units/Units.html">Units</a></span></dt>
 <dd><dl>
 <dt><span class="section"><a href="boost_units/Units.html#boost_units.Units.base_units">Base Units</a></span></dt>
 <dt><span class="section"><a href="boost_units/Units.html#boost_units.Units.scaled_base_units">Scaled Base Units</a></span></dt>
 <dt><span class="section"><a href="boost_units/Units.html#boost_units.Units.scaled_units">Scaled Units</a></span></dt>
 </dl></dd>
 <dt><span class="section"><a href="boost_units/Quantities.html">Quantities</a></span></dt>
 <dd><dl>
 <dt><span class="section"><a href="boost_units/Quantities.html#boost_units.Quantities.Heterogeneous_Operators">Heterogeneous
       Operators</a></span></dt>
 <dt><span class="section"><a href="boost_units/Quantities.html#boost_units.Quantities.Conversions">Conversions</a></span></dt>
 <dt><span class="section"><a href="boost_units/Quantities.html#boost_units.Quantities.Quantity_Construction_and_Conversion">Construction
       and Conversion of Quantities</a></span></dt>
 </dl></dd>
 <dt><span class="section"><a href="boost_units/Examples.html">Examples</a></span></dt>
 <dd><dl>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.DimensionExample">Dimension Example</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.UnitExample">Unit Example</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.QuantityExample">Quantity Example</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.KitchenSinkExample">Kitchen Sink
       Example using SI units</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.ConversionExample">Conversion Example</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.UDTExample">User Defined Types</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.ComplexExample">Complex Example</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.PerformanceExample">Performance
       Example</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.RadarBeamHeightExample">Radar Beam
       Height</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.HeterogeneousUnitExample">Heterogeneous
       Unit Example</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.AbsoluteRelativeTemperatureExample">Absolute
       and Relative Temperature Example</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.RuntimeConversionFactorExample">Runtime
       Conversion Factor Example</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.UnitsWithNonbaseDimensions">Units
       with Non-base Dimensions</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.OutputForCompositeUnits">Output
       for Composite Units</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.autoscale">Automatically Scaled
       Units</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.ConversionFactor">Conversion Factor</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.RuntimeUnits">Runtime Units</a></span></dt>
 <dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.lambda">Interoperability with Boost.Lambda</a></span></dt>
 </dl></dd>
 <dt><span class="section"><a href="boost_units/Utilities.html">Utilities</a></span></dt>
 <dd><dl>
 <dt><span class="section"><a href="boost_units/Utilities.html#boost_units.Utilities.Metaprogramming_Classes">Metaprogramming
       Classes</a></span></dt>
 <dt><span class="section"><a href="boost_units/Utilities.html#boost_units.Utilities.Metaprogramming_Predicates">Metaprogramming
       Predicates</a></span></dt>
 </dl></dd>
 <dt><span class="section"><a href="boost_units/Reference.html">Reference</a></span></dt>
 <dd><dl>
 <dt><span class="section"><a href="boost_units/Reference.html#units_reference">Units Reference</a></span></dt>
 <dt><span class="section"><a href="boost_units/Reference.html#dimensions_reference">Dimensions Reference</a></span></dt>
 <dt><span class="section"><a href="boost_units/Reference.html#si_system_reference">SI System Reference</a></span></dt>
 <dt><span class="section"><a href="boost_units/Reference.html#cgs_system_reference">CGS System Reference</a></span></dt>
 <dt><span class="section"><a href="boost_units/Reference.html#trigonometry_and_angle_system_reference">Trigonometry and Angle System Reference</a></span></dt>
 <dt><span class="section"><a href="boost_units/Reference.html#temperature_system_reference">Temperature System Reference</a></span></dt>
 <dt><span class="section"><a href="boost_units/Reference.html#abstract_system_reference">Abstract System Reference</a></span></dt>
 <dt><span class="section"><a href="boost_units/Reference.html#boost_units.Reference.base_units_by_category">Base Units
       by Category</a></span></dt>
 <dt><span class="section"><a href="boost_units/Reference.html#boost_units.Reference.alphabetical_listing_of_base_units">Alphabetical
       Listing of Base Units</a></span></dt>
 </dl></dd>
 <dt><span class="section"><a href="boost_units/Installation.html">Installation</a></span></dt>
 <dt><span class="section"><a href="boost_units/FAQ.html">FAQ</a></span></dt>
 <dd><dl>
 <dt><span class="section"><a href="boost_units/FAQ.html#boost_units.FAQ.Distinguishing_Quantities_With_Same_Units">How
       does one distinguish between quantities that are physically different but have
       the same units (such as energy and torque)?</a></span></dt>
 <dt><span class="section"><a href="boost_units/FAQ.html#boost_units.FAQ.Angle_Are_Units">Angles are treated as
       units</a></span></dt>
 <dt><span class="section"><a href="boost_units/FAQ.html#boost_units.FAQ.Why_Homogeneous_Systems">Why are there
       homogeneous systems? Aren't heterogeneous systems sufficient?</a></span></dt>
 <dt><span class="section"><a href="boost_units/FAQ.html#boost_units.FAQ.NoConstructorFromValueType">Why can't
       I construct a quantity directly from the value type?</a></span></dt>
 <dt><span class="section"><a href="boost_units/FAQ.html#boost_units.FAQ.ExplicitConversions">Why are conversions
       explicit by default?</a></span></dt>
 </dl></dd>
 <dt><span class="section"><a href="boost_units/Acknowledgements.html">Acknowledgements</a></span></dt>
 <dt><span class="section"><a href="boost_units/HelpWanted.html">Help Wanted</a></span></dt>
 <dt><span class="section"><a href="boost_units/version_id.html">Version Info</a></span></dt>
 <dt><span class="section"><a href="boost_units/ReleaseNotes.html">Release Notes</a></span></dt>
 <dt><span class="section"><a href="boost_units/TODO.html">TODO</a></span></dt>
 </dl>
 </div>
 <div class="section">
 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
 <a name="boost_units.Introduction"></a><a class="link" href="boost_units.html#boost_units.Introduction" title="Introduction">Introduction</a>
 </h2></div></div></div>
 <p>
       The Boost.Units library is a C++ implementation of dimensional analysis in
       a general and extensible manner, treating it as a generic compile-time metaprogramming
       problem. With appropriate compiler optimization, no runtime execution cost
       is introduced, facilitating the use of this library to provide dimension checking
       in performance-critical code. Support for units and quantities (defined as
       a unit and associated value) for arbitrary unit system models and arbitrary
       value types is provided, as is a fine-grained general facility for unit conversions.
       Complete SI and CGS unit systems are provided, along with systems for angles
       measured in degrees, radians, gradians, and revolutions and systems for temperatures
       measured in Kelvin, degrees Celsius and degrees Fahrenheit. The library architecture
       has been designed with flexibility and extensibility in mind; demonstrations
       of the ease of adding new units and unit conversions are provided in the examples.
     </p>
 <p>
       In order to enable complex compile-time dimensional analysis calculations with
       no runtime overhead, Boost.Units relies heavily on the <span class="underline"><a href="http://www.boost.org/libs/mpl/doc/index.html" target="_top">Boost Metaprogramming Library</a></span>
       (MPL) and on template metaprogramming techniques, and is, as a consequence,
       fairly demanding of compiler compliance to ISO standards. At present, it has
       been successfully compiled and tested on the following compilers/platforms
       :
     </p>
 <div class="orderedlist"><ol class="orderedlist" type="1">
 <li class="listitem">
           g++ 4.0.1 on Mac OSX 10.4
         </li>
 <li class="listitem">
           Intel CC 9.1, 10.0, and 10.1 on Mac OSX 10.4
         </li>
 <li class="listitem">
           g++ 3.4.4, 4.2.3, and 4.3.0 on Windows XP
         </li>
 <li class="listitem">
           Microsoft Visual C++ 7.1, 8.0, and 9.0 on Windows XP
         </li>
 <li class="listitem">
           Comeau 4.3.10.1 beta2 on Windows XP
         </li>
 <li class="listitem">
           Metrowerks CodeWarrior 9.2 on Windows XP.
         </li>
 <li class="listitem">
           Sun CC 5.9 on Solaris and Linux
         </li>
 </ol></div>
 <p>
       The following compilers/platforms are known <span class="bold"><strong>not</strong></span>
       to work :
     </p>
 <div class="orderedlist"><ol class="orderedlist" type="1">
 <li class="listitem">
           g++ 3.3.x
         </li>
 <li class="listitem">
           Microsoft Visual C++ 6.0 on Windows XP
         </li>
 <li class="listitem">
           Microsoft Visual C++ 7.0 on Windows XP
         </li>
 <li class="listitem">
           Metrowerks CodeWarrior 8.0 on Windows XP.
         </li>
 <li class="listitem">
           All versions of Borland.
         </li>
 </ol></div>
 </div>
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 <td align="left"><p><small>Last revised: November 10, 2010 at 00:45:35 GMT</small></p></td>
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	<div><h2 class="title">
	<a name="boost_units"></a>Chapter 26. Boost.Units 1.1.0</h2></div>
	<div><div class="author"><h3 class="author">
	<span class="firstname">Matthias C.</span> <span class="surname">Schabel</span>
	</h3></div></div>
	<div><div class="author"><h3 class="author">
	<span class="firstname">Steven</span> <span class="surname">Watanabe</span>
	</h3></div></div>
	<div><p class="copyright">Copyright © 2003 -2008 Matthias Christian Schabel, 2007-2010 Steven
	Watanabe</p></div>
	<div><div class="legalnotice">
	<a name="id2768850"></a><p>
	Distributed under the Boost Software License, Version 1.0. (See accompanying
	file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
	</p>
	</div></div>
	</div></div>
	<div class="toc">
	<p><b>Table of Contents</b></p>
	<dl>
	<dt><span class="section"><a href="boost_units.html#boost_units.Introduction">Introduction</a></span></dt>
	<dt><span class="section"><a href="boost_units/Quick_Start.html">Quick Start</a></span></dt>
	<dt><span class="section"><a href="boost_units/Dimensional_Analysis.html">Dimensional Analysis</a></span></dt>
	<dt><span class="section"><a href="boost_units/Units.html">Units</a></span></dt>
	<dd><dl>
	<dt><span class="section"><a href="boost_units/Units.html#boost_units.Units.base_units">Base Units</a></span></dt>
	<dt><span class="section"><a href="boost_units/Units.html#boost_units.Units.scaled_base_units">Scaled Base Units</a></span></dt>
	<dt><span class="section"><a href="boost_units/Units.html#boost_units.Units.scaled_units">Scaled Units</a></span></dt>
	</dl></dd>
	<dt><span class="section"><a href="boost_units/Quantities.html">Quantities</a></span></dt>
	<dd><dl>
	<dt><span class="section"><a href="boost_units/Quantities.html#boost_units.Quantities.Heterogeneous_Operators">Heterogeneous
	Operators</a></span></dt>
	<dt><span class="section"><a href="boost_units/Quantities.html#boost_units.Quantities.Conversions">Conversions</a></span></dt>
	<dt><span class="section"><a href="boost_units/Quantities.html#boost_units.Quantities.Quantity_Construction_and_Conversion">Construction
	and Conversion of Quantities</a></span></dt>
	</dl></dd>
	<dt><span class="section"><a href="boost_units/Examples.html">Examples</a></span></dt>
	<dd><dl>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.DimensionExample">Dimension Example</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.UnitExample">Unit Example</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.QuantityExample">Quantity Example</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.KitchenSinkExample">Kitchen Sink
	Example using SI units</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.ConversionExample">Conversion Example</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.UDTExample">User Defined Types</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.ComplexExample">Complex Example</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.PerformanceExample">Performance
	Example</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.RadarBeamHeightExample">Radar Beam
	Height</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.HeterogeneousUnitExample">Heterogeneous
	Unit Example</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.AbsoluteRelativeTemperatureExample">Absolute
	and Relative Temperature Example</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.RuntimeConversionFactorExample">Runtime
	Conversion Factor Example</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.UnitsWithNonbaseDimensions">Units
	with Non-base Dimensions</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.OutputForCompositeUnits">Output
	for Composite Units</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.autoscale">Automatically Scaled
	Units</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.ConversionFactor">Conversion Factor</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.RuntimeUnits">Runtime Units</a></span></dt>
	<dt><span class="section"><a href="boost_units/Examples.html#boost_units.Examples.lambda">Interoperability with Boost.Lambda</a></span></dt>
	</dl></dd>
	<dt><span class="section"><a href="boost_units/Utilities.html">Utilities</a></span></dt>
	<dd><dl>
	<dt><span class="section"><a href="boost_units/Utilities.html#boost_units.Utilities.Metaprogramming_Classes">Metaprogramming
	Classes</a></span></dt>
	<dt><span class="section"><a href="boost_units/Utilities.html#boost_units.Utilities.Metaprogramming_Predicates">Metaprogramming
	Predicates</a></span></dt>
	</dl></dd>
	<dt><span class="section"><a href="boost_units/Reference.html">Reference</a></span></dt>
	<dd><dl>
	<dt><span class="section"><a href="boost_units/Reference.html#units_reference">Units Reference</a></span></dt>
	<dt><span class="section"><a href="boost_units/Reference.html#dimensions_reference">Dimensions Reference</a></span></dt>
	<dt><span class="section"><a href="boost_units/Reference.html#si_system_reference">SI System Reference</a></span></dt>
	<dt><span class="section"><a href="boost_units/Reference.html#cgs_system_reference">CGS System Reference</a></span></dt>
	<dt><span class="section"><a href="boost_units/Reference.html#trigonometry_and_angle_system_reference">Trigonometry and Angle System Reference</a></span></dt>
	<dt><span class="section"><a href="boost_units/Reference.html#temperature_system_reference">Temperature System Reference</a></span></dt>
	<dt><span class="section"><a href="boost_units/Reference.html#abstract_system_reference">Abstract System Reference</a></span></dt>
	<dt><span class="section"><a href="boost_units/Reference.html#boost_units.Reference.base_units_by_category">Base Units
	by Category</a></span></dt>
	<dt><span class="section"><a href="boost_units/Reference.html#boost_units.Reference.alphabetical_listing_of_base_units">Alphabetical
	Listing of Base Units</a></span></dt>
	</dl></dd>
	<dt><span class="section"><a href="boost_units/Installation.html">Installation</a></span></dt>
	<dt><span class="section"><a href="boost_units/FAQ.html">FAQ</a></span></dt>
	<dd><dl>
	<dt><span class="section"><a href="boost_units/FAQ.html#boost_units.FAQ.Distinguishing_Quantities_With_Same_Units">How
	does one distinguish between quantities that are physically different but have
	the same units (such as energy and torque)?</a></span></dt>
	<dt><span class="section"><a href="boost_units/FAQ.html#boost_units.FAQ.Angle_Are_Units">Angles are treated as
	units</a></span></dt>
	<dt><span class="section"><a href="boost_units/FAQ.html#boost_units.FAQ.Why_Homogeneous_Systems">Why are there
	homogeneous systems? Aren't heterogeneous systems sufficient?</a></span></dt>
	<dt><span class="section"><a href="boost_units/FAQ.html#boost_units.FAQ.NoConstructorFromValueType">Why can't
	I construct a quantity directly from the value type?</a></span></dt>
	<dt><span class="section"><a href="boost_units/FAQ.html#boost_units.FAQ.ExplicitConversions">Why are conversions
	explicit by default?</a></span></dt>
	</dl></dd>
	<dt><span class="section"><a href="boost_units/Acknowledgements.html">Acknowledgements</a></span></dt>
	<dt><span class="section"><a href="boost_units/HelpWanted.html">Help Wanted</a></span></dt>
	<dt><span class="section"><a href="boost_units/version_id.html">Version Info</a></span></dt>
	<dt><span class="section"><a href="boost_units/ReleaseNotes.html">Release Notes</a></span></dt>
	<dt><span class="section"><a href="boost_units/TODO.html">TODO</a></span></dt>
	</dl>
	</div>
	<div class="section">
	<div class="titlepage"><div><div><h2 class="title" style="clear: both">
	<a name="boost_units.Introduction"></a><a class="link" href="boost_units.html#boost_units.Introduction" title="Introduction">Introduction</a>
	</h2></div></div></div>
	<p>
	The Boost.Units library is a C++ implementation of dimensional analysis in
	a general and extensible manner, treating it as a generic compile-time metaprogramming
	problem. With appropriate compiler optimization, no runtime execution cost
	is introduced, facilitating the use of this library to provide dimension checking
	in performance-critical code. Support for units and quantities (defined as
	a unit and associated value) for arbitrary unit system models and arbitrary
	value types is provided, as is a fine-grained general facility for unit conversions.
	Complete SI and CGS unit systems are provided, along with systems for angles
	measured in degrees, radians, gradians, and revolutions and systems for temperatures
	measured in Kelvin, degrees Celsius and degrees Fahrenheit. The library architecture
	has been designed with flexibility and extensibility in mind; demonstrations
	of the ease of adding new units and unit conversions are provided in the examples.
	</p>
	<p>
	In order to enable complex compile-time dimensional analysis calculations with
	no runtime overhead, Boost.Units relies heavily on the <span class="underline"><a href="http://www.boost.org/libs/mpl/doc/index.html" target="_top">Boost Metaprogramming Library</a></span>
	(MPL) and on template metaprogramming techniques, and is, as a consequence,
	fairly demanding of compiler compliance to ISO standards. At present, it has
	been successfully compiled and tested on the following compilers/platforms
	:
	</p>
	<div class="orderedlist"><ol class="orderedlist" type="1">
	<li class="listitem">
	g++ 4.0.1 on Mac OSX 10.4
	</li>
	<li class="listitem">
	Intel CC 9.1, 10.0, and 10.1 on Mac OSX 10.4
	</li>
	<li class="listitem">
	g++ 3.4.4, 4.2.3, and 4.3.0 on Windows XP
	</li>
	<li class="listitem">
	Microsoft Visual C++ 7.1, 8.0, and 9.0 on Windows XP
	</li>
	<li class="listitem">
	Comeau 4.3.10.1 beta2 on Windows XP
	</li>
	<li class="listitem">
	Metrowerks CodeWarrior 9.2 on Windows XP.
	</li>
	<li class="listitem">
	Sun CC 5.9 on Solaris and Linux
	</li>
	</ol></div>
	<p>
	The following compilers/platforms are known <span class="bold"><strong>not</strong></span>
	to work :
	</p>
	<div class="orderedlist"><ol class="orderedlist" type="1">
	<li class="listitem">
	g++ 3.3.x
	</li>
	<li class="listitem">
	Microsoft Visual C++ 6.0 on Windows XP
	</li>
	<li class="listitem">
	Microsoft Visual C++ 7.0 on Windows XP
	</li>
	<li class="listitem">
	Metrowerks CodeWarrior 8.0 on Windows XP.
	</li>
	<li class="listitem">
	All versions of Borland.
	</li>
	</ol></div>
	</div>
	</div>
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	<td align="left"><p><small>Last revised: November 10, 2010 at 00:45:35 GMT</small></p></td>
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