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<H2><A NAME="SECTION00052000000000000000">
4.2 Memory requirements</A>
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<P>
A typical self-consistency or molecular-dynamics run requires a maximum
memory in the order of <I>O</I> double precision complex numbers, where
<P><!-- MATH
\begin{displaymath}
O = m M N + P N + p N_1 N_2 N_3 + q N_{r1} N_{r2} N_{r3}
\end{displaymath}
-->
</P>
<DIV ALIGN="CENTER">
<I>O</I> = <I>mMN</I> + <I>PN</I> + <I>pN</I><SUB>1</SUB><I>N</I><SUB>2</SUB><I>N</I><SUB>3</SUB> + <I>qN</I><SUB>r1</SUB><I>N</I><SUB>r2</SUB><I>N</I><SUB>r3</SUB>
</DIV><P></P>
with <I>m</I>, <I>p</I>, <I>q</I> = small factors; all other variables have the same meaning as
above. Note that if the <IMG
WIDTH="16" HEIGHT="16" ALIGN="BOTTOM" BORDER="0"
SRC="img7.png"
ALT="$ \Gamma$"> -point only (<I>k</I> = 0) is used to sample the
Brillouin Zone, the value of N will be cut into half.
<P>
The memory required by the phonon code follows the same patterns, with
somewhat larger factors <I>m</I>, <I>p</I>, <I>q</I>.
<P>
<BR><HR>
<ADDRESS>
paolo giannozzi
2014-05-28
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