1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<HEAD>
<TITLE>get_constr_value</TITLE>
<style TYPE="text/css"> BODY { font-family:verdana,arial,helvetica; margin:0; }
</style>
</HEAD>
<BODY>
<TABLE class="clsContainer" style="TABLE-LAYOUT: fixed" cellSpacing="0" cellPadding="15"
width="100%" border="0">
<TR>
<TD vAlign="top">
<h1>get_constr_value</h1>
<p>Gets the value of a constraint according to provided variable values.</p>
<p><b>REAL get_constr_value(lprec </b>*<i>lp</i><b>, int </b><i>row</i><b>, int </b><i>count</i><b>, REAL </b>*<i>primsolution</i><b>, int </b>*<i>nzindex</i><b>);</b></p>
<p class="label"><b>Return Value</b></p>
<p><b>get_constr_value</b> returns the value of the constraint as calculated with the provided variable values.</p>
<p class="label"><b>Parameters</b></p>
<p class="dt"><i>lp</i></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>row</i></p>
<p class="indent">The row for which the constraint value must be calculated. Must be
between 1 and number of rows in the lp.</p>
<p class="dt"><i>count</i></p>
<p class="indent">The number of items in <i>primsolution</i> and <i>nzindex</i>.</p>
<p class="dt"><i>primsolution</i></p>
<p class="indent">The values of the variables.</p>
<p class="dt"><i>nzindex</i></p>
<p class="indent">The variable indexes.</p>
<p class="label"><b>Remarks</b></p>
<p>The <b>get_constr_value</b> function returns the value of a constraint according to provided variable values.<br>
If <i>primsolution</i> is NULL, then the solution of the last solve is taken. <i>count</i> and <i>nzindex</i> are then ignored.<br>
If <i>primsolution</i> is not NULL, and <i>nzindex</i> is NULL, then the variable values are taken from <i>primsolution</i> and element i
must specify the value for variable i. Element 0 is not used and thus data starts from element 1. The variable must then contain
1+<A href="get_Ncolumns.htm">get_Ncolumns</A> elements. <i>count</i> is ignored in that case.<br>
If <i>primsolution</i> is not NULL, and <i>nzindex</i> is not NULL, then the variable values are taken from <i>primsolution</i>.
<i>nzindex</i> contains the indexes of the variables and <i>count</i> specifies how many elements there are in <i>primsolution</i> and <i>nzindex</i>.
So the data is then provided in a sparse vector. Elements start from index 0 in that case.
</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;
int constr;
/* Create a new LP model */
lp = make_lp(1, 0);
if(lp == NULL) {
fprintf(stderr, "Unable to create new LP model\n");
return(1);
}
solve(lp);
printf("%f\n", get_constr_value(lp, 0, 0, NULL, NULL));
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="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_constraints.htm">get_constraints, get_ptr_constraints</a>, <a href="get_variables.htm">get_variables, get_ptr_variables</a>, <a href="get_primal_solution.htm">
get_primal_solution, get_ptr_primal_solution, get_var_primalresult</a></p>
</TD>
</TR>
</TABLE>
</BODY>
</html>
|
