Documentation

showproblem

Display optimization problem

Description

example

showproblem(prob) displays the objective function, constraints, and bounds of prob.

Examples

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Create an optimization problem, including an objective function and constraints, and display the problem.

Create the problem in Mixed-Integer Linear Programming Basics: Problem-Based.

steelprob = optimproblem;
ingots = optimvar('ingots',4,1,'Type','integer','LowerBound',0,'UpperBound',1);
alloys = optimvar('alloys',4,1,'LowerBound',0);
weightIngots = [5,3,4,6];
costIngots = weightIngots.*[350,330,310,280];
costAlloys = [500,450,400,100];
cost = costIngots*ingots + costAlloys*alloys;
steelprob.Objective = cost;
totalweight = weightIngots*ingots + sum(alloys);
carbonIngots = [5,4,5,3]/100;
carbonAlloys = [8,7,6,3]/100;
totalCarbon = (weightIngots.*carbonIngots)*ingots + carbonAlloys*alloys;
molybIngots = [3,3,4,4,]/100;
molybAlloys = [6,7,8,9]/100;
totalMolyb = (weightIngots.*molybIngots)*ingots + molybAlloys*alloys;
steelprob.Constraints.conswt = totalweight == 25;
steelprob.Constraints.conscarb = totalCarbon == 1.25;
steelprob.Constraints.consmolyb = totalMolyb == 1.25;

Display the problem.

showproblem(steelprob)
OptimizationProblem :

Solve for:
alloys, ingots

minimize :
1750*ingots(1) + 990*ingots(2) + 1240*ingots(3) + 1680*ingots(4)
+ 500*alloys(1) + 450*alloys(2) + 400*alloys(3) + 100*alloys(4)

subject to conswt:
5*ingots(1) + 3*ingots(2) + 4*ingots(3) + 6*ingots(4) + alloys(1)
+ alloys(2) + alloys(3) + alloys(4) == 25

subject to conscarb:
0.25*ingots(1) + 0.12*ingots(2) + 0.2*ingots(3) + 0.18*ingots(4)
+ 0.08*alloys(1) + 0.07*alloys(2) + 0.06*alloys(3) + 0.03*alloys(4) == 1.25

subject to consmolyb:
0.15*ingots(1) + 0.09*ingots(2) + 0.16*ingots(3) + 0.24*ingots(4)
+ 0.06*alloys(1) + 0.07*alloys(2) + 0.08*alloys(3) + 0.09*alloys(4) == 1.25

variable bounds:
0 <= alloys(1)
0 <= alloys(2)
0 <= alloys(3)
0 <= alloys(4)

0 <= ingots(1) <= 1
0 <= ingots(2) <= 1
0 <= ingots(3) <= 1
0 <= ingots(4) <= 1

Input Arguments

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Optimization problem or equation problem, specified as an OptimizationProblem object or an EquationProblem object. Create an optimization problem by using optimproblem; create an equation problem by using eqnproblem.

Warning

The problem-based approach does not support complex values in an objective function, nonlinear equalities, or nonlinear inequalities. If a function calculation has a complex value, even as an intermediate value, the final result can be incorrect.

Example: prob = optimproblem; prob.Objective = obj; prob.Constraints.cons1 = cons1;

Example: prob = eqnproblem; prob.Equations = eqs;

Tips

• showproblem is equivalent to calling all of the following:

• For a problem that has many bounds or constraints, use writeproblem to generate a text file containing the objective, constraint, and bound information.

Compatibility Considerations

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Not recommended starting in R2019b