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<H2><A NAME="SECTION00057000000000000000">
psb_geasums -- Generalized 1-Norm of Vector</A>
</H2>

<P>
This subroutine computes a series of  1-norms on the columns of
a  dense matrix  <IMG
 WIDTH="14" HEIGHT="13" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$">: 
<BR><P></P>
<DIV ALIGN="CENTER">
<!-- MATH
 \begin{displaymath}
res(i) \leftarrow \max_k |x(k,i)|
\end{displaymath}
 -->

<IMG
 WIDTH="147" HEIGHT="36" BORDER="0"
 SRC="img32.png"
 ALT="\begin{displaymath}res(i) \leftarrow \max_k \vert x(k,i)\vert \end{displaymath}">
</DIV>
<BR CLEAR="ALL">
<P></P>
This function computes the 1-norm of a vector <IMG
 WIDTH="14" HEIGHT="13" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$">.
<BR>
If <IMG
 WIDTH="14" HEIGHT="13" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"> is a real vector 
it computes 1-norm as:
<BR><P></P>
<DIV ALIGN="CENTER">
<!-- MATH
 \begin{displaymath}
res(i) \leftarrow  \|x_i\|
\end{displaymath}
 -->

<IMG
 WIDTH="94" HEIGHT="28" BORDER="0"
 SRC="img36.png"
 ALT="\begin{displaymath}res(i) \leftarrow \Vert x_i\Vert\end{displaymath}">
</DIV>
<BR CLEAR="ALL">
<P></P>
else if <IMG
 WIDTH="14" HEIGHT="13" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"> is a complex vector then it computes 1-norm  as:
<BR><P></P>
<DIV ALIGN="CENTER">
<!-- MATH
 \begin{displaymath}
res(i) \leftarrow \|re(x)\|_1 + \|im(x)\|_1
\end{displaymath}
 -->

<IMG
 WIDTH="206" HEIGHT="28" BORDER="0"
 SRC="img37.png"
 ALT="\begin{displaymath}res(i) \leftarrow \Vert re(x)\Vert _1 + \Vert im(x)\Vert _1\end{displaymath}">
</DIV>
<BR CLEAR="ALL">
<P></P>

<P>
<PRE>
call psb_geasums(res, x, desc_a, info)
</PRE>

<P>
<BR><P></P>
<DIV ALIGN="CENTER"><A NAME="1644"></A>
<TABLE>
<CAPTION><STRONG>Table 7:</STRONG>
Data types</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">
<TABLE CELLPADDING=3 BORDER="1" ALIGN="CENTER">
<TR><TD ALIGN="LEFT"><IMG
 WIDTH="27" HEIGHT="13" ALIGN="BOTTOM" BORDER="0"
 SRC="img28.png"
 ALT="$res$"></TD>
<TD ALIGN="LEFT"><IMG
 WIDTH="14" HEIGHT="13" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"></TD>
<TD ALIGN="LEFT"><B>Subroutine</B></TD>
</TR>
<TR><TD ALIGN="LEFT">Short Precision Real</TD>
<TD ALIGN="LEFT">Short Precision Real</TD>
<TD ALIGN="LEFT">psb_geasums</TD>
</TR>
<TR><TD ALIGN="LEFT">Long Precision Real</TD>
<TD ALIGN="LEFT">Long Precision Real</TD>
<TD ALIGN="LEFT">psb_geasums</TD>
</TR>
<TR><TD ALIGN="LEFT">Short Precision Real</TD>
<TD ALIGN="LEFT">Short Precision Complex</TD>
<TD ALIGN="LEFT">psb_geasums</TD>
</TR>
<TR><TD ALIGN="LEFT">Long Precision Real</TD>
<TD ALIGN="LEFT">Long Precision Complex</TD>
<TD ALIGN="LEFT">psb_geasums</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="13" 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:f90asums">7</A>.
</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>.

<P>
</DD>
<DT><STRONG><B>On Return</B></STRONG></DT>
<DD>
</DD>
<DT><STRONG>res</STRONG></DT>
<DD>contains the 1-norm of (the columns of) <IMG
 WIDTH="14" HEIGHT="13" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$">.
<BR>
Scope: <B>global</B> 
<BR>
Intent: <B>out</B>.
<BR>
Short as: a long precision real  number.
Specified as: a long precision real  number.
</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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