Making GEKKO results.csv Files More Readable by Naming Variables Explicitly

Learn how to improve the readability of GEKKO output CSV files by assigning meaningful names to variables and intermediates in your optimization models.
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This video is based on the question https://stackoverflow.com/q/79485958/ asked by the user 'Hamiduddin Hamdan' ( https://stackoverflow.com/u/29675788/ ) and on the answer https://stackoverflow.com/a/79487578/ provided by the user 'John Hedengren' ( https://stackoverflow.com/u/2366941/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Introduction

When using GEKKO for optimization in Python, the default output CSV (results.csv) can be hard to interpret. Variables often appear with generic names like i1000 for intermediates, making it difficult to relate values back to your model.

This post shows how to assign custom, descriptive names to your variables and intermediate results, resulting in a more readable output file.



Problem

GEKKO outputs variable names like i1000 instead of your meaningful variable names.

Using m.Array for variable arrays doesn’t automatically assign user-friendly names with indices.

Example confusing output:

[[See Video to Reveal this Text or Code Snippet]]



Solution: Assign Variable Names Explicitly

Instead of using m.Array which doesn’t allow custom names conveniently, use a list comprehension to create variables with explicit names. This works similarly for intermediates.

Step-by-step Example

[[See Video to Reveal this Text or Code Snippet]]

Result:

Your results.csv will contain the variable names you assigned:

[[See Video to Reveal this Text or Code Snippet]]

Note: APMonitor automatically converts variable names to lowercase.



Important Tips

Avoid starting variable names with reserved function names like sin, cos, abs as this may cause conflicts.

Explicitly naming variables improves readability and debugging.

Using list comprehensions offers flexible naming for indexed variables.



Summary

To make your GEKKO optimization results easier to read:

Define variables with explicit name parameters rather than relying on default unnamed arrays.

Name intermediates similarly for clarity.

This practice produces clear, user-friendly CSV output for analysis or reports.

With these changes, your GEKKO workflow becomes more transparent and maintainable.