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<h1>SRC/dgssv.c File Reference</h1>Solves the system of linear equations A*X=B. <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="dgssv_8c.html#d804a93a6806ee4d4694df5b753d91af">dgssv</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 *perm_r, <a class="el" href="structSuperMatrix.html">SuperMatrix</a> *L, <a class="el" href="structSuperMatrix.html">SuperMatrix</a> *U, <a class="el" href="structSuperMatrix.html">SuperMatrix</a> *B, <a class="el" href="structSuperLUStat__t.html">SuperLUStat_t</a> *stat, int *info)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Driver routines. <a href="#d804a93a6806ee4d4694df5b753d91af"></a><br></td></tr>
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<hr><a name="_details"></a><h2>Detailed Description</h2>
<pre>
-- SuperLU routine (version 3.0) --
Univ. of California Berkeley, Xerox Palo Alto Research Center,
and Lawrence Berkeley National Lab.
October 15, 2003
</pre> <hr><h2>Function Documentation</h2>
<a class="anchor" name="d804a93a6806ee4d4694df5b753d91af"></a><!-- doxytag: member="dgssv.c::dgssv" ref="d804a93a6806ee4d4694df5b753d91af" args="(superlu_options_t *options, SuperMatrix *A, int *perm_c, int *perm_r, SuperMatrix *L, SuperMatrix *U, SuperMatrix *B, SuperLUStat_t *stat, int *info)" -->
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<td class="memname">void dgssv </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="paramkey"></td>
<td></td>
<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="paramkey"></td>
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<td class="paramtype">int * </td>
<td class="paramname"> <em>perm_r</em>, </td>
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<td class="paramkey"></td>
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<td class="paramtype"><a class="el" href="structSuperMatrix.html">SuperMatrix</a> * </td>
<td class="paramname"> <em>L</em>, </td>
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<td class="paramkey"></td>
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<td class="paramtype"><a class="el" href="structSuperMatrix.html">SuperMatrix</a> * </td>
<td class="paramname"> <em>U</em>, </td>
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<td class="paramtype"><a class="el" href="structSuperMatrix.html">SuperMatrix</a> * </td>
<td class="paramname"> <em>B</em>, </td>
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<td class="paramkey"></td>
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<td class="paramtype"><a class="el" href="structSuperLUStat__t.html">SuperLUStat_t</a> * </td>
<td class="paramname"> <em>stat</em>, </td>
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<td class="paramtype">int * </td>
<td class="paramname"> <em>info</em></td><td> </td>
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<p>
<pre>
Purpose
=======</pre><p>
<pre> DGSSV solves the system of linear equations A*X=B, using the
LU factorization from DGSTRF. It performs the following steps:</pre><p>
<pre> 1. If A is stored column-wise (A->Stype = SLU_NC):</pre><p>
<pre> 1.1. Permute the columns of A, forming A*Pc, where Pc
is a permutation matrix. For more details of this step,
see <a class="el" href="sp__preorder_8c.html" title="Permute and performs functions on columns of orginal matrix.">sp_preorder.c</a>.</pre><p>
<pre> 1.2. Factor A as Pr*A*Pc=L*U with the permutation Pr determined
by Gaussian elimination with partial pivoting.
L is unit lower triangular with offdiagonal entries
bounded by 1 in magnitude, and U is upper triangular.</pre><p>
<pre> 1.3. Solve the system of equations A*X=B using the factored
form of A.</pre><p>
<pre> 2. If A is stored row-wise (A->Stype = SLU_NR), apply the
above algorithm to the transpose of A:</pre><p>
<pre> 2.1. Permute columns of transpose(A) (rows of A),
forming transpose(A)*Pc, where Pc is a permutation matrix.
For more details of this step, see <a class="el" href="sp__preorder_8c.html" title="Permute and performs functions on columns of orginal matrix.">sp_preorder.c</a>.</pre><p>
<pre> 2.2. Factor A as Pr*transpose(A)*Pc=L*U with the permutation Pr
determined by Gaussian elimination with partial pivoting.
L is unit lower triangular with offdiagonal entries
bounded by 1 in magnitude, and U is upper triangular.</pre><p>
<pre> 2.3. Solve the system of equations A*X=B using the factored
form of A.</pre><p>
<pre> See <a class="el" href="supermatrix_8h.html" title="Defines matrix types.">supermatrix.h</a> for the definition of 'SuperMatrix' structure.</pre><p>
<pre> Arguments
=========</pre><p>
<pre> options (input) superlu_options_t*
The structure defines the input parameters to control
how the LU decomposition will be performed and how the
system will be solved.</pre><p>
<pre> A (input) SuperMatrix*
Matrix A in A*X=B, of dimension (A->nrow, A->ncol). The number
of linear equations is A->nrow. Currently, the type of A can be:
Stype = SLU_NC or SLU_NR; Dtype = SLU_D; Mtype = SLU_GE.
In the future, more general A may be handled.</pre><p>
<pre> perm_c (input/output) int*
If A->Stype = SLU_NC, 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 A->Stype = SLU_NR, column permutation vector of size A->nrow
which describes permutation of columns of transpose(A)
(rows of A) as described above.</pre><p>
<pre> If options->ColPerm = MY_PERMC or options->Fact = SamePattern or
options->Fact = SamePattern_SameRowPerm, it is an input argument.
On exit, perm_c may be overwritten by the product of the input
perm_c and a permutation that postorders the elimination tree
of Pc'*A'*A*Pc; perm_c is not changed if the elimination tree
is already in postorder.
Otherwise, it is an output argument.</pre><p>
<pre> perm_r (input/output) int*
If A->Stype = SLU_NC, row permutation vector of size A->nrow,
which defines the permutation matrix Pr, and is determined
by partial pivoting. perm_r[i] = j means row i of A is in
position j in Pr*A.
If A->Stype = SLU_NR, permutation vector of size A->ncol, which
determines permutation of rows of transpose(A)
(columns of A) as described above.</pre><p>
<pre> If options->RowPerm = MY_PERMR or
options->Fact = SamePattern_SameRowPerm, perm_r is an
input argument.
otherwise it is an output argument.</pre><p>
<pre> L (output) SuperMatrix*
The factor L from the factorization
Pr*A*Pc=L*U (if A->Stype = SLU_NC) or
Pr*transpose(A)*Pc=L*U (if A->Stype = SLU_NR).
Uses compressed row subscripts storage for supernodes, i.e.,
L has types: Stype = SLU_SC, Dtype = SLU_D, Mtype = SLU_TRLU.</pre><p>
<pre> U (output) SuperMatrix*
The factor U from the factorization
Pr*A*Pc=L*U (if A->Stype = SLU_NC) or
Pr*transpose(A)*Pc=L*U (if A->Stype = SLU_NR).
Uses column-wise storage scheme, i.e., U has types:
Stype = SLU_NC, Dtype = SLU_D, Mtype = SLU_TRU.</pre><p>
<pre> B (input/output) SuperMatrix*
B has types: Stype = SLU_DN, Dtype = SLU_D, Mtype = SLU_GE.
On entry, the right hand side matrix.
On exit, the solution matrix if info = 0;</pre><p>
<pre> stat (output) SuperLUStat_t*
Record the statistics on runtime and floating-point operation count.
See util.h for the definition of 'SuperLUStat_t'.</pre><p>
<pre> info (output) int*
= 0: successful exit
> 0: if info = i, and i is
<= A->ncol: U(i,i) is exactly zero. The factorization has
been completed, but the factor U is exactly singular,
so the solution could not be computed.
> A->ncol: number of bytes allocated when memory allocation
failure occurred, plus A->ncol.
</pre>
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