Pivot Calculator Simplex Method

Build each simplex pivot from tableau inputs. Track ratios, bases, reduced costs, and objective changes. Export results while learning every optimization step with checks.

Simplex Pivot Calculator

Use commas, spaces, or semicolons. Keep RHS as the last column. Keep the objective row at the bottom.

Example Data Table

Basis x y s1 s2 s3 RHS
s1 1 0 1 0 0 4
s2 0 2 0 1 0 12
s3 3 2 0 0 1 18
Objective -3 -5 0 0 0 0

Formula Used

Entering column: for a common maximization tableau, choose the most negative reduced cost. Bland rule uses the first valid candidate.

Ratio test: divide RHS by the positive entering column value. The smallest nonnegative ratio gives the leaving row.

Pivot row: new pivot row equals old pivot row divided by the pivot element.

Other rows: new row equals old row minus row factor multiplied by the new pivot row.

How To Use This Calculator

Enter the complete simplex tableau. Put the right side values in the final column. Put the objective row last. Add variable names and basis names. Select automatic, manual, or iterative mode. Press submit. Review the ratio table, pivot element, final basis, and updated tableau.

Simplex Pivot Planning

A simplex tableau turns a linear program into rows of numbers. Each row shows one constraint. The final row shows the objective change. A pivot moves the solution from one corner point to another. The aim is better profit, lower cost, or another chosen target.

Why The Pivot Matters

The entering column tells which variable should grow next. The leaving row tells which basic variable must leave. The pivot element sits where that row and column meet. Dividing the pivot row by this element creates a leading one. Then each other row is cleaned to zero in that column.

Advanced Use Cases

This calculator is useful for classroom checks, tutoring pages, and planning notes. It accepts a full tableau, custom variable names, and custom basis names. You can run one pivot, choose a manual pivot, or continue through several iterations. Ratio tests help explain why a row leaves. Tableau history helps show every move.

Reading The Result

Look first at the selected entering variable. Then check the ratio table. Only rows with positive pivot column values can leave. The smallest nonnegative ratio wins. If no valid row exists, the model is unbounded under the selected rule. If no entering column exists, the tableau is optimal for the chosen direction.

Practical Tips

Use clean numbers when learning the method. Fractions can be entered as decimals. Keep the right side as the last column. Keep the objective row at the bottom. For a common maximization tableau, profit coefficients often appear as negative values in the objective row. Different textbooks may use different signs. Match the calculator setting to your tableau style.

Export And Review

The CSV button saves the calculated tableau for spreadsheets. The PDF button gives a compact report. Use both downloads when preparing assignments or review notes. The example table shows the expected layout. Replace it with your own data. Then inspect each pivot before trusting the final answer.

Limitations

This tool checks arithmetic and pivot logic. It does not prove your original model was written correctly. Confirm constraints, units, and objective direction first. Then use the result as a clear simplex pivot guide. Save each run, compare choices, and document every assumption before sharing answers clearly.

FAQs

What is a simplex pivot?

A simplex pivot is one tableau operation. It swaps one entering variable into the basis and moves one leaving variable out.

Which row should leave the basis?

The leaving row is found by the ratio test. Use positive entering column values only. Pick the smallest nonnegative RHS ratio.

Can I enter fractions?

Yes. You may enter values like 1/2 or 3/4. The calculator converts valid fractions into decimal values.

What does unbounded mean?

Unbounded means no valid leaving row exists for the selected entering column. The objective can improve without a limiting constraint.

Why is the objective row last?

The algorithm reads the last row as the objective row. It uses that row to select entering columns and detect stopping.

What is Bland rule?

Bland rule picks the first eligible entering column. It is often used to reduce cycling risk in special simplex cases.

What does tolerance control?

Tolerance treats very tiny values as zero. It helps avoid unstable decisions caused by floating point rounding.

Can this solve every linear program?

No. The tableau must be prepared correctly first. The calculator checks pivot arithmetic, not the full modeling process.

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