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<div id="version" align=right><b>petsc-3.4.2 2013-07-02</b></div>
<A NAME="VecDotRealPart"><H1>VecDotRealPart</H1></A>
Computes the real part of the vector dot product.
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscvec.h"
PetscErrorCode VecDotRealPart(Vec x,Vec y,PetscReal *val)
</PRE>
Collective on <A HREF="../Vec/Vec.html#Vec">Vec</A>
<P>
<H3><FONT COLOR="#CC3333">Input Parameters</FONT></H3>
<DT><B>x, y </B> -the vectors
<br>
<P>
<H3><FONT COLOR="#CC3333">Output Parameter</FONT></H3>
<DT><B>val </B> -the real part of the dot product;
<br>
<P>
<H3><FONT COLOR="#CC3333">Performance Issues</FONT></H3>
<pre>
per-processor memory bandwidth
</pre>
<pre>
interprocessor latency
</pre>
<pre>
work load inbalance that causes certain processes to arrive much earlier than others
</pre>
<P>
<H3><FONT COLOR="#CC3333">Notes for Users of Complex Numbers</FONT></H3>
See <A HREF="../Vec/VecDot.html#VecDot">VecDot</A>() for more details on the definition of the dot product for complex numbers
<P>
For real numbers this returns the same value as <A HREF="../Vec/VecDot.html#VecDot">VecDot</A>()
<P>
For complex numbers in C^n (that is a vector of n components with a complex number for each component) this is equal to the usual real dot product on the
the space R^{2n} (that is a vector of 2n components with the real or imaginary part of the complex numbers for components)
<P>
Developer Note: This is not currently optimized to compute only the real part of the dot product.
<P>
<P>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../Vec/VecMDot.html#VecMDot">VecMDot</A>(), <A HREF="../Vec/VecTDot.html#VecTDot">VecTDot</A>(), <A HREF="../Vec/VecNorm.html#VecNorm">VecNorm</A>(), <A HREF="../Vec/VecDotBegin.html#VecDotBegin">VecDotBegin</A>(), <A HREF="../Vec/VecDotEnd.html#VecDotEnd">VecDotEnd</A>(), <A HREF="../Vec/VecDot.html#VecDot">VecDot</A>(), <A HREF="../Vec/VecDotNorm2.html#VecDotNorm2">VecDotNorm2</A>()
<BR><P><B><P><B><FONT COLOR="#CC3333">Level:</FONT></B>intermediate
<BR><FONT COLOR="#CC3333">Location:</FONT></B><A HREF="../../../src/vec/vec/interface/rvector.c.html#VecDotRealPart">src/vec/vec/interface/rvector.c</A>
<BR><A HREF="./index.html">Index of all Vec routines</A>
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