h02bzf extracts more information associated with the solution of an integer programming problem computed by
h02bbf.
h02bzf extracts the following information associated with the solution of an integer programming problem computed by
h02bbf. The upper and lower bounds used for the solution, the Lagrange-multipliers (costs), and the status of the variables at the solution.
In the branch and bound method employed by
h02bbf, the arrays
bl and
bu are used to impose restrictions on the values of the integer variables in each sub-problem. That is, if the variable
${x}_{j}$ is restricted to take value
${v}_{j}$ in a particular sub-problem, then
${\mathbf{bl}}\left(j\right)={\mathbf{bu}}\left(j\right)={v}_{j}$ is set in the sub-problem. Thus, on exit from this routine, some of the elements of
bl and
bu which correspond to integer variables may contain these imposed values, rather than those originally supplied to
h02bbf.
None.
If on entry
${\mathbf{ifail}}=0$ or
$-1$, explanatory error messages are output on the current error message unit (as defined by
x04aaf).
Not applicable.
None.
One of the applications of integer programming is to the so-called diet problem. Given the nutritional content of a selection of foods, the cost of each food, the amount available of each food and the consumer's minimum daily nutritional requirements, the problem is to find the cheapest combination. This gives rise to the following problem:
The following program solves the above problem to obtain the optimal integer solution and then examines the effect of increasing the energy required to $2200$ units.