Monotonic Sequence Test Calculator

Check monotonic patterns across custom number lists. Measure changes, tolerance effects, and turning points accurately. Use responsive inputs, exports, examples, formulas, and helpful guidance.

Enter sequence data

Use commas, spaces, semicolons, or new lines between numbers. The calculator checks each adjacent pair and applies your chosen tolerance.

Differences within ±tolerance are treated as equal.

Formula used

For a sequence a₁, a₂, ..., aₙ, the calculator evaluates adjacent differences using:

Δᵢ = aᵢ₊₁ − aᵢ

A reversal occurs whenever nonzero difference signs switch from positive to negative, or from negative to positive.

How to use this calculator

  1. Enter at least two numbers in the sequence box.
  2. Select a target test or leave automatic classification enabled.
  3. Set a tolerance when small measurement noise should count as equal.
  4. Choose your preferred decimal precision and index base.
  5. Press Test Sequence to show results above the form.
  6. Review the summary, pairwise differences, and violation notes.
  7. Download the calculated output as CSV or PDF when needed.

Example data table

Example Sequence Tolerance Expected Classification Why
2, 4, 7, 10, 15 0 Strictly increasing Every adjacent difference is positive.
3, 3, 5, 5, 9 0 Non-decreasing Equal ties appear, but no decrease occurs.
12, 9, 9, 5, 2 0 Non-increasing No step rises above the previous value.
1, 4, 3, 6, 5 0 Not monotonic Positive and negative differences both appear.

FAQs

1. What does monotonic mean in this calculator?

A monotonic sequence keeps moving in one direction or stays level. It can rise throughout, fall throughout, or remain flat within the tolerance you selected.

2. What is the difference between strict and weak monotonicity?

Strict monotonicity allows no equal neighboring values. Weak monotonicity permits ties, so a sequence may stay the same temporarily while still counting as non-decreasing or non-increasing.

3. Why is tolerance useful?

Tolerance helps when data includes rounding noise, sensor error, or very small fluctuations. Values changing less than the tolerance are treated as effectively equal during the test.

4. Can the calculator test decreasing sequences?

Yes. You can test strict decreasing, non-increasing, or let automatic classification decide whether the sequence trends upward, downward, stays constant, or breaks monotonicity.

5. What causes a sequence to fail the test?

A sequence fails when one or more adjacent differences violate the chosen rule. For example, a negative step breaks increasing behavior, while a positive step breaks decreasing behavior.

6. What does the trend score show?

The trend score summarizes directional balance. Positive values suggest more upward moves, negative values suggest more downward moves, and values near zero indicate mixed behavior.

7. How are reversals counted?

A reversal is counted whenever meaningful differences switch direction. Flat steps within tolerance are ignored, so only actual sign changes between rising and falling moves are counted.

8. Can I export the result for reporting?

Yes. The page includes CSV and PDF download buttons after a successful calculation, letting you save the summary, pairwise differences, and any violation notes.

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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.