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<h1>get_column, get_columnex</h1>
<p>
Get all (get_column) or only the non-zero (get_columnex) column elements from the matrix.</p>
<p>
<b>unsigned char get_column(lprec </b>*<i>lp</i><b>, int </b><i>col_nr</i><b>, REAL </b>*<i>column</i><b>);</b><br>
<b>int get_columnex(lprec </b>*<i>lp</i><b>, int </b><i>col_nr</i><b>, REAL </b>*<i>column</i><b>, int </b>*<i>nzrow</i><b>);</b></p>
<p class="label">
<b>Return Value</b></p>
<p>
<b>get_column</b> returns TRUE (1) if the operation was successful. A return
value of FALSE (0) indicates an error.<br>
<b>get_columnex</b> returns the number of non-zero elements returned in <i>column</i> and <i>nzrow</i>. If an error occurs, then -1 is returned.<br>
An error occurs when <i>col_nr</i> is not between 1 and the number of columns
in the lp.<br>
Note that row entry mode must be off, else these functions also fail. See <A HREF="set_add_rowmode.htm">set_add_rowmode</A>
</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>col_nr</i></p>
<p class="indent">
Column number of the matrix. Must be between 1 and number of columns in the lp.</p>
<p class="dt">
<i>column</i></p>
<p class="indent">
Array in which the values are returned. For get_column, the array must be dimensioned with at
least 1<A HREF="get_Nrows.htm">get_Nrows</A> elements in the lp. For get_columnex, the array must be dimentioned with at
least the number of non-zero elements in the column. If that is unknown, then use 1+<A HREF="get_Nrows.htm">get_Nrows</A> in the lp.
The return value of the function indicates how many non-zero elements there are.</p>
<p class="dt">
<i>nzrow</i></p>
<p class="indent">
Array in which the row numbers are returned. The array must be dimentioned with at
least the number of non-zero elements in the column. If that is unknown, then use 1+<A HREF="get_Nrows.htm">get_Nrows</A> in the lp.
The return value of the function indicates how many non-zero elements there are.</p>
<p class="label">
<b>Remarks</b></p>
<p>
get_column retrieves all values for the given column.<br>
Element 0 of the <i>column</i> array will contain the value of the objective
function, element 1 will contain the value for column 1, Element 2 the value
for column 2, ...<br>
get_columnex retrieves only the non-zero values for a given column.<br>
Returned values in <i>column</i> and <i>nzrow</i> start from element 0.
</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;
REAL column[1+2]; /* must be 1 greater than number of rows ! */
/* Create a new LP model */
lp = make_lp(2, 1);
if(lp == NULL) {
fprintf(stderr, "Unable to create new LP model\n");
return(1);
}
get_column(lp, 1, column);
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_mat.htm">get_mat</A>, <A HREF="get_row.htm">
get_row, get_rowex</A>, <A HREF="set_row.htm">set_row, set_rowex</A>, <A HREF="set_rh.htm">set_rh</A>, <A HREF="set_rh_vec.htm">set_rh_vec,
str_set_rh_vec</A>, <A HREF="add_constraint.htm">add_constraint, add_constraintex, str_add_constraint</A>, <A HREF="add_column.htm">
add_column, add_columnex, str_add_column</A>, <A HREF="set_column.htm">set_column, set_columnex</A></p>
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