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<div id="version" align=right><b>petsc-3.14.5 2021-03-03</b></div>
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<A NAME="PetscDTEnumPerm"><H1>PetscDTEnumPerm</H1></A>
Get a permutation of n integers from its encoding into the integers [0, n!) as a sequence of swaps. A permutation can be described by the operations that convert the lists [0, 1, ..., n-1] into the permutation,
by a sequence of swaps, where the ith step swaps whatever number is in ith position with a number that is in
some position j >= i. This swap is encoded as the difference (j - i). The difference d_i at step i is less than
(n - i). This sequence of n-1 differences [d_0, ..., d_{n-2}] is encoded as the number
(n-1)! * d_0 + (n-2)! * d_1 + ... + 1! * d_{n-2}.
<P>
<H3><FONT COLOR="#CC3333">Input Arguments</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>n </B></TD><TD>- a non-negative integer (see note about limits below)
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>k </B></TD><TD>- an integer in [0, n!)
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Output Arguments</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>perm </B></TD><TD>- the permuted list of the integers [0, ..., n-1]
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>isOdd </B></TD><TD>- if not NULL, returns wether the permutation used an even or odd number of swaps.
</TD></TR></TABLE>
<P>
Note: this is limited to n such that n! can be represented by <A HREF="../Sys/PetscInt.html#PetscInt">PetscInt</A>, which is 12 if <A HREF="../Sys/PetscInt.html#PetscInt">PetscInt</A> is a signed 32-bit integer and 20 if <A HREF="../Sys/PetscInt.html#PetscInt">PetscInt</A> is a signed 64-bit integer.
<P>
<P><B></B><H3><FONT COLOR="#CC3333">Level</FONT></H3>beginner<BR>
<H3><FONT COLOR="#CC3333">Location</FONT></H3>
</B><A HREF="../../../src/dm/dt/../../../include/petscdt.h.html#PetscDTEnumPerm">src/dm/dt/../../../include/petscdt.h</A>
<BR><A HREF="./index.html">Index of all DM routines</A>
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