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<h1>set_basiscrash</h1>
<p>
Determines a starting base.</p>
<p>
<b>void set_basiscrash(lprec </b>*<i>lp</i><b>, int </b><i>mode</i><b>);</b></p>
<p class="label">
<b>Return Value</b></p>
<p>
None</p>
<p class="label">
<b>Parameters</b></p>
<p class="indent">
Pointer to previously created lp model. See return value of <A HREF="make_lp.htm">make_lp</A>, <A HREF="copy_lp.htm">copy_lp</A>,
<A HREF="read_lp.htm">read_lp, read_LP</A>, <A HREF="read_mps.htm">read_mps, read_freemps, read_MPS, read_freeMPS</A>, <A HREF="read_XLI.htm">read_XLI</A></p>
<p class="dt">
<i>mode</i></p>
<p class="indent">Specifies which basis crash mode is used. Can by any of the
following values:</p>
<TABLE id="Table1" cellSpacing="1" cellPadding="1" border="1">
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<TD>CRASH_NONE (0)</TD>
<TD>No basis crash</TD>
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<!--
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<TD>CRASH_NONBASICBOUNDS (1)</TD>
<TD> </TD>
</TR>
-->
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<TD>CRASH_MOSTFEASIBLE (2)</TD>
<TD>Most feasible basis</TD>
</TR>
<TR>
<TD>CRASH_LEASTDEGENERATE (3)</TD>
<TD>Construct a basis that is in some measure the "least degenerate"</TD>
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<p class="label">
<b>Remarks</b></p>
<p>
The <b>set_basiscrash</b> function specifies which basis crash mode must be used.
Default is CRASH_NONE.
</p>
<p>When no base crash is done (the default), the initial basis from which
lp_solve starts to solve the model is the basis containing all slack or
artificial variables that is automatically associates with each constraint.</p>
<p>When base crash is enabled, a heuristic ``crash procedure'' is executed
before the first simplex iteration to quickly choose a basis matrix that has
fewer artificial variables. This procedure tends to reduce the number of
iterations to optimality since a number of iterations are skipped. lp_solve
starts iterating from this basis until optimality.</p>
<p class="label">
<b>Example</b></p>
<pre><code>#include <stdio.h>
#include <stdlib.h>
#include "lp_lib.h"
int main(void)
{
lprec *lp;
/* Create a new LP model */
lp = make_lp(0, 0);
if(lp == NULL) {
fprintf(stderr, "Unable to create new LP model\n");
return(1);
}
/* Model created */
set_basiscrash(lp, CRASH_MOSTFEASIBLE);
delete_lp(lp);
return(0);
}
</code></pre>
<p>
<A HREF="lp_solveAPIreference.htm">lp_solve API reference</A></p>
<p>
<b>See Also</b> <A HREF="make_lp.htm">make_lp</A>, <A HREF="copy_lp.htm">copy_lp</A>, <A HREF="copy_lp.htm">copy_lp</A>, <A href="read_lp.htm">read_lp,
read_LP</A>, <A HREF="read_mps.htm">
read_mps, read_freemps, read_MPS, read_freeMPS</A>, <A HREF="read_XLI.htm">read_XLI</A>, <A HREF="get_basiscrash.htm">get_basiscrash</A>, <A HREF="default_basis.htm">
default_basis</A>, <A HREF="read_basis.htm">read_basis</A>, <A HREF="write_basis.htm">write_basis</A>, <a href="guess_basis.htm">guess_basis</a>, <A HREF="get_basis.htm">get_basis</A>, <A HREF="set_basis.htm">
set_basis</A></p>
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