<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1">
<title>Flags</title>
<link href="doxygen.css" rel="stylesheet" type="text/css">
<link href="tabs.css" rel="stylesheet" type="text/css">
</head><body>
<div align="left"><a href="http://www.mrpt.org/">Main MRPT website</a> > <b>C++ reference</b> </div>
<div align="right">
<a href="index.html"><img border="0" src="mrpt_logo.png" alt="MRPT logo"></a>
</div>
<!-- Generated by Doxygen 1.7.5 -->
<script type="text/javascript">
var searchBox = new SearchBox("searchBox", "search",false,'Search');
</script>
<div id="navrow1" class="tabs">
<ul class="tablist">
<li><a href="index.html"><span>Main Page</span></a></li>
<li><a href="pages.html"><span>Related Pages</span></a></li>
<li><a href="modules.html"><span>Modules</span></a></li>
<li><a href="namespaces.html"><span>Namespaces</span></a></li>
<li><a href="annotated.html"><span>Classes</span></a></li>
<li><a href="files.html"><span>Files</span></a></li>
<li>
<div id="MSearchBox" class="MSearchBoxInactive">
<div class="left">
<form id="FSearchBox" action="search.php" method="get">
<img id="MSearchSelect" src="search/mag.png" alt=""/>
<input type="text" id="MSearchField" name="query" value="Search" size="20" accesskey="S"
onfocus="searchBox.OnSearchFieldFocus(true)"
onblur="searchBox.OnSearchFieldFocus(false)"/>
</form>
</div><div class="right"></div>
</div>
</li>
</ul>
</div>
</div>
<div class="header">
<div class="summary">
<a href="#var-members">Variables</a> </div>
<div class="headertitle">
<div class="title">Flags</div> </div>
<div class="ingroups"><a class="el" href="group__eigen__grp.html">The Eigen3 library</a> | <a class="el" href="group___core___module.html">Core module</a></div></div>
<div class="contents">
<hr/><a name="details" id="details"></a><h2>Detailed Description</h2>
<p>These are the possible bits which can be OR'ed to constitute the flags of a matrix or expression. </p>
<p>It is important to note that these flags are a purely compile-time notion. They are a compile-time property of an expression type, implemented as enum's. They are not stored in memory at runtime, and they do not incur any runtime overhead.</p>
<dl class="see"><dt><b>See also:</b></dt><dd><a class="el" href="class_eigen_1_1_dense_base.html#ae4670c2813cc711a1c145ecd2e861444acc15d9abc2cffc86674403f4939fc667" title="This stores expression Flags flags which may or may not be inherited by new expressions constructed f...">MatrixBase::Flags</a> </dd></dl>
<div class="dynheader">
Collaboration diagram for Flags:</div>
<div class="dyncontent">
<center><table><tr><td><img src="group__flags.png" border="0" alt="" usemap="#group____flags"/>
<map name="group____flags" id="group____flags">
<area shape="rect" id="node1" href="group___core___module.html" title="This is the main module of Eigen providing dense matrix and vector support (both fixed and dynamic si..." alt="" coords="21,5,117,32"/><area shape="rect" id="node2" href="group__eigen__grp.html" title="The Eigen3 library" alt="" coords="6,56,133,83"/></map>
</td></tr></table></center>
</div>
<table class="memberdecls">
<tr><td colspan="2"><h2><a name="var-members"></a>
Variables</h2></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const unsigned int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__flags.html#gae4f56c2a60bbe4bd2e44c5b19cbe8762">Eigen::RowMajorBit</a> = 0x1</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">for a matrix, this means that the storage order is row-major. <a href="#gae4f56c2a60bbe4bd2e44c5b19cbe8762"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const unsigned int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__flags.html#gaa34e83bae46a8eeae4e69ebe3aaecbed">Eigen::EvalBeforeNestingBit</a> = 0x2</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">means the expression should be evaluated by the calling expression <a href="#gaa34e83bae46a8eeae4e69ebe3aaecbed"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const unsigned int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__flags.html#ga9e8cc99f33fd2f5d89c3b6c83fb2dc48">Eigen::EvalBeforeAssigningBit</a> = 0x4</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">means the expression should be evaluated before any assignment <a href="#ga9e8cc99f33fd2f5d89c3b6c83fb2dc48"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const unsigned int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__flags.html#ga1a306a438e1ab074e8be59512e887b9f">Eigen::PacketAccessBit</a> = 0x8</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Short version: means the expression might be vectorized. <a href="#ga1a306a438e1ab074e8be59512e887b9f"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const unsigned int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__flags.html#ga4b983a15d57cd55806df618ac544d09e">Eigen::LinearAccessBit</a> = 0x10</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Short version: means the expression can be seen as 1D vector. <a href="#ga4b983a15d57cd55806df618ac544d09e"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const unsigned int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__flags.html#gae2c323957f20dfdc6cb8f44428eaec1a">Eigen::LvalueBit</a> = 0x20</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Means the expression has a coeffRef() method, i.e. <a href="#gae2c323957f20dfdc6cb8f44428eaec1a"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const unsigned int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__flags.html#gabf1e9d0516a933445a4c307ad8f14915">Eigen::DirectAccessBit</a> = 0x40</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Means that the underlying array of coefficients can be directly accessed as a plain strided array. <a href="#gabf1e9d0516a933445a4c307ad8f14915"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const unsigned int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__flags.html#ga157ebfd0ca896e8be3f3c7747fda4eee">Eigen::AlignedBit</a> = 0x80</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">means the first coefficient packet is guaranteed to be aligned <a href="#ga157ebfd0ca896e8be3f3c7747fda4eee"></a><br/></td></tr>
</table>
<hr/><h2>Variable Documentation</h2>
<a class="anchor" id="ga157ebfd0ca896e8be3f3c7747fda4eee"></a><!-- doxytag: member="Eigen::AlignedBit" ref="ga157ebfd0ca896e8be3f3c7747fda4eee" args="" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">const unsigned int <a class="el" href="group__flags.html#ga157ebfd0ca896e8be3f3c7747fda4eee">Eigen::AlignedBit</a> = 0x80</td>
</tr>
</table>
</div>
<div class="memdoc">
<p>means the first coefficient packet is guaranteed to be aligned </p>
<p>Definition at line <a class="el" href="_core_source.html#l00158">158</a> of file <a class="el" href="_core_source.html">Core</a>.</p>
</div>
</div>
<a class="anchor" id="gabf1e9d0516a933445a4c307ad8f14915"></a><!-- doxytag: member="Eigen::DirectAccessBit" ref="gabf1e9d0516a933445a4c307ad8f14915" args="" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">const unsigned int <a class="el" href="group__flags.html#gabf1e9d0516a933445a4c307ad8f14915">Eigen::DirectAccessBit</a> = 0x40</td>
</tr>
</table>
</div>
<div class="memdoc">
<p>Means that the underlying array of coefficients can be directly accessed as a plain strided array. </p>
<p>The memory layout of the array of coefficients must be exactly the natural one suggested by rows(), cols(), outerStride(), innerStride(), and the RowMajorBit. This rules out expressions such as <a class="el" href="class_eigen_1_1_diagonal.html" title="Expression of a diagonal/subdiagonal/superdiagonal in a matrix.">Diagonal</a>, whose coefficients, though referencable, do not have such a regular memory layout.</p>
<p>See the comment on LvalueBit for an explanation of how LvalueBit and DirectAccessBit are mutually orthogonal. </p>
<p>Definition at line <a class="el" href="_core_source.html#l00153">153</a> of file <a class="el" href="_core_source.html">Core</a>.</p>
</div>
</div>
<a class="anchor" id="ga9e8cc99f33fd2f5d89c3b6c83fb2dc48"></a><!-- doxytag: member="Eigen::EvalBeforeAssigningBit" ref="ga9e8cc99f33fd2f5d89c3b6c83fb2dc48" args="" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">const unsigned int <a class="el" href="group__flags.html#ga9e8cc99f33fd2f5d89c3b6c83fb2dc48">Eigen::EvalBeforeAssigningBit</a> = 0x4</td>
</tr>
</table>
</div>
<div class="memdoc">
<p>means the expression should be evaluated before any assignment </p>
<p>Definition at line <a class="el" href="_core_source.html#l00074">74</a> of file <a class="el" href="_core_source.html">Core</a>.</p>
</div>
</div>
<a class="anchor" id="gaa34e83bae46a8eeae4e69ebe3aaecbed"></a><!-- doxytag: member="Eigen::EvalBeforeNestingBit" ref="gaa34e83bae46a8eeae4e69ebe3aaecbed" args="" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">const unsigned int <a class="el" href="group__flags.html#gaa34e83bae46a8eeae4e69ebe3aaecbed">Eigen::EvalBeforeNestingBit</a> = 0x2</td>
</tr>
</table>
</div>
<div class="memdoc">
<p>means the expression should be evaluated by the calling expression </p>
<p>Definition at line <a class="el" href="_core_source.html#l00069">69</a> of file <a class="el" href="_core_source.html">Core</a>.</p>
</div>
</div>
<a class="anchor" id="ga4b983a15d57cd55806df618ac544d09e"></a><!-- doxytag: member="Eigen::LinearAccessBit" ref="ga4b983a15d57cd55806df618ac544d09e" args="" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">const unsigned int <a class="el" href="group__flags.html#ga4b983a15d57cd55806df618ac544d09e">Eigen::LinearAccessBit</a> = 0x10</td>
</tr>
</table>
</div>
<div class="memdoc">
<p>Short version: means the expression can be seen as 1D vector. </p>
<p>Long version: means that one can access the coefficients of this expression by coeff(int), and coeffRef(int) in the case of a lvalue expression. These index-based access methods are guaranteed to not have to do any runtime computation of a (row, col)-pair from the index, so that it is guaranteed that whenever it is available, index-based access is at least as fast as (row,col)-based access. Expressions for which that isn't possible don't have the LinearAccessBit.</p>
<p>If both PacketAccessBit and LinearAccessBit are set, then the packets of this expression can be accessed by packet(int), and writePacket(int) in the case of a lvalue expression.</p>
<p>Typically, all vector expressions have the LinearAccessBit, but there is one exception: Product expressions don't have it, because it would be troublesome for vectorization, even when the Product is a vector expression. Thus, vector Product expressions allow index-based coefficient access but not index-based packet access, so they don't have the LinearAccessBit. </p>
<p>Definition at line <a class="el" href="_core_source.html#l00128">128</a> of file <a class="el" href="_core_source.html">Core</a>.</p>
</div>
</div>
<a class="anchor" id="gae2c323957f20dfdc6cb8f44428eaec1a"></a><!-- doxytag: member="Eigen::LvalueBit" ref="gae2c323957f20dfdc6cb8f44428eaec1a" args="" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">const unsigned int <a class="el" href="group__flags.html#gae2c323957f20dfdc6cb8f44428eaec1a">Eigen::LvalueBit</a> = 0x20</td>
</tr>
</table>
</div>
<div class="memdoc">
<p>Means the expression has a coeffRef() method, i.e. </p>
<p>is writable as its individual coefficients are directly addressable. This rules out read-only expressions.</p>
<p>Note that DirectAccessBit and LvalueBit are mutually orthogonal, as there are examples of expression having one but note the other: </p>
<ul>
<li>writable expressions that don't have a very simple memory layout as a strided array, have LvalueBit but not DirectAccessBit </li>
<li>Map-to-const expressions, for example Map<const Matrix>, have DirectAccessBit but not LvalueBit</li>
</ul>
<p>Expressions having LvalueBit also have their coeff() method returning a const reference instead of returning a new value. </p>
<p>Definition at line <a class="el" href="_core_source.html#l00142">142</a> of file <a class="el" href="_core_source.html">Core</a>.</p>
</div>
</div>
<a class="anchor" id="ga1a306a438e1ab074e8be59512e887b9f"></a><!-- doxytag: member="Eigen::PacketAccessBit" ref="ga1a306a438e1ab074e8be59512e887b9f" args="" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">const unsigned int <a class="el" href="group__flags.html#ga1a306a438e1ab074e8be59512e887b9f">Eigen::PacketAccessBit</a> = 0x8</td>
</tr>
</table>
</div>
<div class="memdoc">
<p>Short version: means the expression might be vectorized. </p>
<p>Long version: means that the coefficients can be handled by packets and start at a memory location whose alignment meets the requirements of the present CPU architecture for optimized packet access. In the fixed-size case, there is the additional condition that it be possible to access all the coefficients by packets (this implies the requirement that the size be a multiple of 16 bytes, and that any nontrivial strides don't break the alignment). In the dynamic-size case, there is no such condition on the total size and strides, so it might not be possible to access all coeffs by packets.</p>
<dl class="note"><dt><b>Note:</b></dt><dd>This bit can be set regardless of whether vectorization is actually enabled. To check for actual vectorizability, see <em>ActualPacketAccessBit</em>. </dd></dl>
<p>Definition at line <a class="el" href="_core_source.html#l00092">92</a> of file <a class="el" href="_core_source.html">Core</a>.</p>
</div>
</div>
<a class="anchor" id="gae4f56c2a60bbe4bd2e44c5b19cbe8762"></a><!-- doxytag: member="Eigen::RowMajorBit" ref="gae4f56c2a60bbe4bd2e44c5b19cbe8762" args="" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">const unsigned int <a class="el" href="group__flags.html#gae4f56c2a60bbe4bd2e44c5b19cbe8762">Eigen::RowMajorBit</a> = 0x1</td>
</tr>
</table>
</div>
<div class="memdoc">
<p>for a matrix, this means that the storage order is row-major. </p>
<p>If this bit is not set, the storage order is column-major. For an expression, this determines the storage order of the matrix created by evaluation of that expression. </p>
<dl class="see"><dt><b>See also:</b></dt><dd>TopicStorageOrders </dd></dl>
<p>Definition at line <a class="el" href="_core_source.html#l00064">64</a> of file <a class="el" href="_core_source.html">Core</a>.</p>
</div>
</div>
</div>
<br><hr><br> <table border="0" width="100%"> <tr> <td> Page generated by <a href="http://www.doxygen.org" target="_blank">Doxygen 1.7.5</a> for MRPT 0.9.5 SVN: at Sun Sep 25 17:20:18 UTC 2011</td><td></td> <td width="100"> </td> <td width="150"> </td></tr> </table> </body></html>
