Factorio Forums

As per title, the Heavy Oil output seems to be calculated incorrectly with Productivity for unclear reasons;

An Oil Refinery with 3x Productivity Module 3 (Base Quality) has a speed of 0.55x, and a Productivity of 1.3x
The Coal Liquefaction recipe takes 5 seconds, and yields 90 Heavy Oil.

So, the heavy oil output should be 90 Heavy/Craft / 5 Crafts/second = 18 Heavy Oil/second * 0.55 craft speed = 9.9 Heavy Oil/s * 1.3 = 12.87 Heavy Oil/s

However, the actual game shows 12.0 Heavy Oil/s in this case, rather than 12.8 or 12.9 (actual rate: 12.87) Strangely, the other two estimates work correctly!

In the case of 0x Productivity 3 modules, the output correctly reads 18 Heavy Oil/s This also happens at 1x Productivity Module; Display is 16.4, should be 16.8 (actual rate: 16.83) And at 2x Productivity Module; Display is 14.4, should be 15.1 (actual rate: 15.12) I do not see this with Advanced Oil Processing, or any other recipe in the Oil Refinery.

While the error scales with machine speed, it's not a 1:1 scaling.
While 1 Prod Mod (0.85 speed) is an error of 0.43, 1 Prod and 1 Speed Mod (1.35 speed) is an error of 0.73. This means that for a speed increase of 58.8%, the error increased 69.8%.

With 2 speed mods, the error is ~0.9, for an increase of 118% in speed and a 109% in error. Playing around with the numbers, I can't come up with any sort of theory for what exactly is going on here, but given that the error is not confined to the last significant digit, this is probably worth looking at.

The productivity bonus only applies to 65 heavy oil (90 output - 25 input). When you take this catalyst into account, the numbers will match:
90 Heavy Oil/Craft / 5 second/Craft * 0.55 craft speed * (1 + 0.3 prod bonus * (90-25)/90 output without catalyst) = 12.045 Heavy Oil/second

Not a Bug.

Ah, ok, that tracks with Kovarex Enrichment. Any chance some marker for catalysts could get added to recipe pages in factoriopedia (ie. 60 Heavy Oil + 25 Catalyst)?