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| Purpose |
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Change the lower or upper bound for a single variable.
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| Synopsis |
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int QSchange_bound (QSprob p, int indx, char lu, double bound)
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| Arguments |
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p |
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a handle to an initialized problem. |
indx |
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the index of the variable whose bound will be changed. |
lu |
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an 'L' to change the lower bound or a 'U' to change an upper bound. |
bound |
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the value of the new bound. |
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| Returns |
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A zero value if the function terminated correctly, and a non-zero value if an error occurred.
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| Description |
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This function can be used to change the lower or upper bound of a single variable. A bound on a variable can be removed by specifying -QS_MAXDOUBLE as a lower bound, or QS_MAXDOUBLE as an upper bound. A common use of this function is to fix a variable at its lower or upper bound, or to change a bound in a step of a branch-and-bound algorithm. When specifying the lower or upper bound, it is important not to give any value larger in magnitude than QS_MAXDOUBLE (1e30). This restriction is due to the internal structures used in the QSopt solvers.
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| Example |
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/* Assume p is initialized to the problem in the QSload_prob example. */
/* Change the lower bound on variable y to 0. */
int rval;
rval = QSchange_bound (p, 1, 'L', 0.0);
if (rval) {
fprintf (stderr,
"Could not change the bound, error code %d\n",rval);
}
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