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<H2><A NAME="SECTION00054000000000000000">
psb_normi -- Infinity-Norm of Vector</A>
</H2>

<P>
This function computes 
 the infinity-norm of a vector <IMG
 WIDTH="13" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$">.
<BR>
If <IMG
 WIDTH="13" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"> is a real  vector
it computes infinity norm as:
<BR><P></P>
<DIV ALIGN="CENTER">
<!-- MATH
 \begin{displaymath}
amax \leftarrow \max_i |x_i|
\end{displaymath}
 -->

<IMG
 WIDTH="118" HEIGHT="36" BORDER="0"
 SRC="img29.png"
 ALT="\begin{displaymath}amax \leftarrow \max_i \vert x_i\vert\end{displaymath}">
</DIV>
<BR CLEAR="ALL">
<P></P>
else if <IMG
 WIDTH="13" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"> is a complex vector then it computes the infinity-norm  as:
<BR><P></P>
<DIV ALIGN="CENTER">
<!-- MATH
 \begin{displaymath}
amax \leftarrow \max_i {(|re(x_i)| + |im(x_i)|)}
\end{displaymath}
 -->

<IMG
 WIDTH="233" HEIGHT="36" BORDER="0"
 SRC="img30.png"
 ALT="\begin{displaymath}amax \leftarrow \max_i {(\vert re(x_i)\vert + \vert im(x_i)\vert)}\end{displaymath}">
</DIV>
<BR CLEAR="ALL">
<P></P>
<P>
<PRE>
psb_geamax(x, desc_a, info)
psb_normi(x, desc_a, info)
</PRE>
<P>
<BR><P></P>
<DIV ALIGN="CENTER"><A NAME="1946"></A>
<TABLE>
<CAPTION><STRONG>Table 4:</STRONG>
Data types</CAPTION>
<TR><TD>
<DIV ALIGN="CENTER">
<TABLE CELLPADDING=3 BORDER="1" ALIGN="CENTER">
<TR><TD ALIGN="LEFT"><IMG
 WIDTH="44" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img31.png"
 ALT="$amax$"></TD>
<TD ALIGN="LEFT"><IMG
 WIDTH="13" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$"></TD>
<TD ALIGN="LEFT"><B>Function</B></TD>
</TR>
<TR><TD ALIGN="LEFT">Short Precision Real</TD>
<TD ALIGN="LEFT">Short Precision Real</TD>
<TD ALIGN="LEFT">psb_geamax</TD>
</TR>
<TR><TD ALIGN="LEFT">Long Precision Real</TD>
<TD ALIGN="LEFT">Long Precision Real</TD>
<TD ALIGN="LEFT">psb_geamax</TD>
</TR>
<TR><TD ALIGN="LEFT">Short Precision Real</TD>
<TD ALIGN="LEFT">Short Precision Complex</TD>
<TD ALIGN="LEFT">psb_geamax</TD>
</TR>
<TR><TD ALIGN="LEFT">Long Precision Real</TD>
<TD ALIGN="LEFT">Long Precision Complex</TD>
<TD ALIGN="LEFT">psb_geamax</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="13" 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:f90amax">4</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>Function value</STRONG></DT>
<DD>is the infinity norm of subvector <IMG
 WIDTH="13" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
 SRC="img20.png"
 ALT="$x$">.
<BR>
Scope: <B>global</B> 
<BR>
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>
<P>
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