Artificial Variable Calculator

Analyze constraints needing artificial variables online. Compare penalties, Phase One totals, and basis choices. Turn equations into organized simplex-ready rows with confidence today.

Use this tool to identify slack, surplus, and artificial variables for simplex preparation. It summarizes starting rows for Big M and Two Phase methods.

Enter Problem Details

Choose a method, enter the objective coefficients, then fill up to four constraints. Use blank zero rows only when not needed.

3 columns on large screens 2 on smaller screens 1 on mobile

Constraint 1

Constraint 2

Constraint 3

Constraint 4

Example Data Table

This sample illustrates a mixed-constraint problem where both surplus and artificial variables are required.

Item Value
Objective Maximize Z = 5x1 + 4x2
Constraint 1 2x1 + x2 ≤ 18
Constraint 2 x1 + 2x2 ≥ 20
Constraint 3 3x1 + x2 = 12
Added Variables s1, e1, A1, A2
Phase One Start W = A1 + A2 = 20 + 12 = 32

Formula Used

1. For a ≤ constraint:
ax1 + bx2 ≤ c becomes ax1 + bx2 + s = c
2. For a ≥ constraint:
ax1 + bx2 ≥ c becomes ax1 + bx2 - e + A = c
3. For an = constraint:
ax1 + bx2 = c becomes ax1 + bx2 + A = c
4. Phase One objective:
Minimize W = sum of all artificial variables
5. Big M objective adjustment:
For maximization, subtract a large penalty M for every artificial variable. For minimization, add a large penalty M for every artificial variable.

This calculator also normalizes rows with negative right-hand sides. It flips the inequality and multiplies the full row by negative one before adding auxiliary variables.

How to Use This Calculator

  1. Select whether your problem is a maximization or minimization model.
  2. Choose Big M or Two Phase according to your preferred simplex setup.
  3. Enter objective coefficients for x1 and x2.
  4. Fill the constraint coefficients, inequality sign, and right-hand side values.
  5. Click the calculate button to identify slack, surplus, and artificial variables.
  6. Review the transformed equations, starting basis variables, and initial artificial totals.
  7. Use the CSV or PDF buttons to save the result for coursework, revision, or documentation.
  8. Check the chart to see which constraints contribute artificial starting values.

Frequently Asked Questions

1. What is an artificial variable?

An artificial variable is a temporary helper variable used to start simplex iterations when a natural starting basis is unavailable. It is removed later from the final solution.

2. When do I need artificial variables?

You usually need them for equality constraints and greater-than-or-equal constraints. Those rows cannot always create an identity basis using only slack or surplus variables.

3. What is the difference between Big M and Two Phase?

Big M adds a large penalty directly into the objective function. Two Phase first minimizes the artificial variables, then solves the original objective after feasibility is established.

4. Why does the calculator flip negative right-hand sides?

A negative right-hand side can complicate basis interpretation. Multiplying the row by negative one creates a cleaner standard form before slack, surplus, or artificial variables are added.

5. Does this calculator solve the full simplex problem?

No. It prepares the constraint rows and starting artificial-variable analysis. Its main goal is to build a simplex-ready representation for study and setup.

6. What does the initial Phase One value mean?

It is the starting sum of artificial basis values after standardization. A zero value at the end of Phase One indicates that a feasible solution has been found.

7. Can I use decimal coefficients?

Yes. The calculator accepts integer and decimal inputs for objective coefficients, constraint coefficients, the right-hand side, and the chosen Big M value.

8. What does the chart display?

The chart displays the initial artificial variable values by constraint. It helps you see which rows create feasibility penalties or contribute to the Phase One objective.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.