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<h1>SRC/sp_preorder.c File Reference</h1>Permute and performs functions on columns of orginal matrix. <a href="#_details">More...</a>
<p>
<code>#include "<a class="el" href="slu__ddefs_8h-source.html">slu_ddefs.h</a>"</code><br>
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<tr><td colspan="2"><br><h2>Functions</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="sp__preorder_8c.html#d3a9a45f02456022c7eba79e17e215bc">sp_preorder</a> (<a class="el" href="structsuperlu__options__t.html">superlu_options_t</a> *options, <a class="el" href="structSuperMatrix.html">SuperMatrix</a> *<a class="el" href="ilu__zdrop__row_8c.html#c900805a486cbb8489e3c176ed6e0d8e">A</a>, int *perm_c, int *etree, <a class="el" href="structSuperMatrix.html">SuperMatrix</a> *AC)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="sp__preorder_8c.html#c79059104ae6abf212c41986820d358c">check_perm</a> (char *what, int n, int *perm)</td></tr>
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<hr><a name="_details"></a><h2>Detailed Description</h2>
<hr><h2>Function Documentation</h2>
<a class="anchor" name="c79059104ae6abf212c41986820d358c"></a><!-- doxytag: member="sp_preorder.c::check_perm" ref="c79059104ae6abf212c41986820d358c" args="(char *what, int n, int *perm)" -->
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<td class="memname">int check_perm </td>
<td>(</td>
<td class="paramtype">char * </td>
<td class="paramname"> <em>what</em>, </td>
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<td class="paramtype">int </td>
<td class="paramname"> <em>n</em>, </td>
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<td class="paramtype">int * </td>
<td class="paramname"> <em>perm</em></td><td> </td>
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<a class="anchor" name="d3a9a45f02456022c7eba79e17e215bc"></a><!-- doxytag: member="sp_preorder.c::sp_preorder" ref="d3a9a45f02456022c7eba79e17e215bc" args="(superlu_options_t *options, SuperMatrix *A, int *perm_c, int *etree, SuperMatrix *AC)" -->
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<td class="memname">void sp_preorder </td>
<td>(</td>
<td class="paramtype"><a class="el" href="structsuperlu__options__t.html">superlu_options_t</a> * </td>
<td class="paramname"> <em>options</em>, </td>
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<td class="paramtype"><a class="el" href="structSuperMatrix.html">SuperMatrix</a> * </td>
<td class="paramname"> <em>A</em>, </td>
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<td class="paramkey"></td>
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<td class="paramtype">int * </td>
<td class="paramname"> <em>perm_c</em>, </td>
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<td class="paramtype">int * </td>
<td class="paramname"> <em>etree</em>, </td>
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<td class="paramtype"><a class="el" href="structSuperMatrix.html">SuperMatrix</a> * </td>
<td class="paramname"> <em>AC</em></td><td> </td>
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<pre>
Purpose
=======</pre><p>
<pre> <a class="el" href="slu__util_8h.html#df9c573cbfb4520a5ea820702d27cfa5">sp_preorder()</a> permutes the columns of the original matrix. It performs
the following steps:</pre><p>
<pre> 1. Apply column permutation perm_c[] to A's column pointers to form AC;</pre><p>
<pre> 2. If options->Fact = DOFACT, then
(1) Compute column elimination tree etree[] of AC'AC;
(2) Post order etree[] to get a postordered elimination tree etree[],
and a postorder permutation post[];
(3) Apply post[] permutation to columns of AC;
(4) Overwrite perm_c[] with the product perm_c * post.</pre><p>
<pre> Arguments
=========</pre><p>
<pre> options (input) superlu_options_t*
Specifies whether or not the elimination tree will be re-used.
If options->Fact == DOFACT, this means first time factor A,
etree is computed, postered, and output.
Otherwise, re-factor A, etree is input, unchanged on exit.</pre><p>
<pre> A (input) SuperMatrix*
Matrix A in A*X=B, of dimension (A->nrow, A->ncol). The number
of the linear equations is A->nrow. Currently, the type of A can be:
Stype = NC or SLU_NCP; Mtype = SLU_GE.
In the future, more general A may be handled.</pre><p>
<pre> perm_c (input/output) int*
Column permutation vector of size A->ncol, which defines the
permutation matrix Pc; perm_c[i] = j means column i of A is
in position j in A*Pc.
If options->Fact == DOFACT, perm_c is both input and output.
On output, it is changed according to a postorder of etree.
Otherwise, perm_c is input.</pre><p>
<pre> etree (input/output) int*
Elimination tree of Pc'*A'*A*Pc, dimension A->ncol.
If options->Fact == DOFACT, etree is an output argument,
otherwise it is an input argument.
Note: etree is a vector of parent pointers for a forest whose
vertices are the integers 0 to A->ncol-1; etree[root]==A->ncol.</pre><p>
<pre> AC (output) SuperMatrix*
The resulting matrix after applied the column permutation
perm_c[] to matrix A. The type of AC can be:
Stype = SLU_NCP; Dtype = A->Dtype; Mtype = SLU_GE.
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