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<H2><A NAME="SECTION00053000000000000000">
psb_gedots -- Generalized Dot Product</A>
</H2>

<P>
This subroutine computes a series of  dot products among the columns of
two dense matrices  <IMG
 WIDTH="14" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"> and <IMG
 WIDTH="13" HEIGHT="30" ALIGN="MIDDLE" BORDER="0"
 SRC="img21.png"
 ALT="$y$">: 
<BR><P></P>
<DIV ALIGN="CENTER">
<!-- MATH
 \begin{displaymath}
res(i) \leftarrow x(:,i)^T y(:,i)
\end{displaymath}
 -->

<IMG
 WIDTH="150" HEIGHT="28" BORDER="0"
 SRC="img27.png"
 ALT="\begin{displaymath}res(i) \leftarrow x(:,i)^T y(:,i)\end{displaymath}">
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<BR CLEAR="ALL">
<P></P>
If the matrices are complex, then the
usual convention applies, i.e. the conjugate transpose of <IMG
 WIDTH="14" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"> is
used. If <IMG
 WIDTH="14" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"> and <IMG
 WIDTH="13" HEIGHT="30" ALIGN="MIDDLE" BORDER="0"
 SRC="img21.png"
 ALT="$y$"> are of rank one, then <IMG
 WIDTH="27" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img28.png"
 ALT="$res$"> is a scalar, else it
is a rank one array. 

<P>
<PRE>
call psb_gedots(res, x, y, desc_a, info)
</PRE>
<BR><P></P>
<DIV ALIGN="CENTER"><A NAME="1945"></A>
<TABLE>
<CAPTION><STRONG>Table 3:</STRONG>
Data types</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">
<TABLE CELLPADDING=3 BORDER="1" ALIGN="CENTER">
<TR><TD ALIGN="LEFT"><IMG
 WIDTH="27" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img28.png"
 ALT="$res$">, <IMG
 WIDTH="14" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$">, <IMG
 WIDTH="13" HEIGHT="30" ALIGN="MIDDLE" BORDER="0"
 SRC="img21.png"
 ALT="$y$"></TD>
<TD ALIGN="LEFT"><B>Subroutine</B></TD>
</TR>
<TR><TD ALIGN="LEFT">Short Precision Real</TD>
<TD ALIGN="LEFT">psb_gedots</TD>
</TR>
<TR><TD ALIGN="LEFT">Long Precision Real</TD>
<TD ALIGN="LEFT">psb_gedots</TD>
</TR>
<TR><TD ALIGN="LEFT">Short Precision Complex</TD>
<TD ALIGN="LEFT">psb_gedots</TD>
</TR>
<TR><TD ALIGN="LEFT">Long Precision Complex</TD>
<TD ALIGN="LEFT">psb_gedots</TD>
</TR>
</TABLE>
</DIV>
</TD></TR>
</TABLE>
</DIV><P></P>
<BR>

<P>
<DL>
<DT><STRONG>Type:</STRONG></DT>
<DD>Synchronous.
</DD>
<DT><STRONG><B>On Entry</B></STRONG></DT>
<DD>
</DD>
<DT><STRONG>x</STRONG></DT>
<DD>the local portion of global dense matrix
<IMG
 WIDTH="14" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$">. 
<BR>
Scope: <B>local</B> 
<BR>
Type: <B>required</B> 
<BR>
Intent: <B>in</B>.
<BR>
Specified as:  a rank one or two array or an object of type vdata<TT>psb_T_vect_type</TT> 
containing numbers of type specified in
Table&nbsp;<A HREF="#tab:f90mdot">3</A>. The rank of <IMG
 WIDTH="14" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"> must be the same of <IMG
 WIDTH="13" HEIGHT="30" ALIGN="MIDDLE" BORDER="0"
 SRC="img21.png"
 ALT="$y$">. 
</DD>
<DT><STRONG>y</STRONG></DT>
<DD>the local portion of global dense matrix
<IMG
 WIDTH="13" HEIGHT="30" ALIGN="MIDDLE" BORDER="0"
 SRC="img21.png"
 ALT="$y$">. 
<BR>
Scope: <B>local</B> 
<BR>
Type: <B>required</B> 
<BR>
Intent: <B>in</B>.
<BR>
Specified as:  a rank one or two array or an object of type vdata<TT>psb_T_vect_type</TT> 
containing numbers of type specified in
Table&nbsp;<A HREF="#tab:f90mdot">3</A>. The rank of <IMG
 WIDTH="13" HEIGHT="30" ALIGN="MIDDLE" BORDER="0"
 SRC="img21.png"
 ALT="$y$"> must be the same of <IMG
 WIDTH="14" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$">. 
</DD>
<DT><STRONG>desc_a</STRONG></DT>
<DD>contains data structures for communications.
<BR>
Scope: <B>local</B> 
<BR>
Type: <B>required</B>
<BR>
Intent: <B>in</B>.
<BR>
Specified as: an object of type descdata<TT>psb_desc_type</TT>.
</DD>
<DT><STRONG><B>On Return</B></STRONG></DT>
<DD>
</DD>
<DT><STRONG>res</STRONG></DT>
<DD>is the dot product of subvectors <IMG
 WIDTH="14" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"> and <IMG
 WIDTH="13" HEIGHT="30" ALIGN="MIDDLE" BORDER="0"
 SRC="img21.png"
 ALT="$y$">.
<BR>
Scope: <B>global</B> 
<BR>
Intent: <B>out</B>.
<BR>
Specified as: a number or a rank-one array  of the data type indicated
in Table&nbsp;<A HREF="#tab:f90dot">2</A>. 
</DD>
<DT><STRONG>info</STRONG></DT>
<DD>Error code.
<BR>
Scope: <B>local</B> 
<BR>
Type: <B>required</B> 
<BR>
Intent: <B>out</B>.
<BR>
An integer value; 0 means no error has been detected. 
</DD>
</DL>

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