I've been going crazy for the past hour trying to figure out how SCV repair calculations work. I already looked at the wiki and I still don't understand. All I know is it's something to do with [hp], [build time], and [cost]. So here's what I need to do...

¤ Must repair 100 hit points in 65 trigger cycles (5.4 seconds) at the cost of 5 ore for a variety of Terran vehicle units, each with different health.

Can anyone show me the calculations for this? My units have the following hit points...

4800
650
550
330

The repair time is set to repair a certain % at a rate similar to the build time. I don't know the exact math, but I messed around in SCMDraft a bit. For the unit with 330 hp, you would want a build time of about 250 in order for it to repair 100 hit points per 5.4 seconds. You would change that build time for the units with bigger HPs, by multiplying it by the ratio of the HPs.

The cost has to do with % of the unit healed compared to the total unit cost. I think it's about 1/3-1/4 the price? So, you would take the 100 damage repaired, divide it into the total unit hp, and then multiply that % by the unit's total cost and the appropriate fraction (1/3-1/4)

According to what i'm reading here...

R = ceil[ .9 * H / B ]

R = repair rate 1hp regened/256frames = ceil[ .9 * H / B ]
H = HP
B = Build Rate (# seen in SCMDraft)

R can also be written... 1*R = (1*hp)/(256*frames), so we can play around with the units easier.

Assuming you are using standard hyper triggers, 1 trigger cycle = 2 frames, we can adjust the units of R so it shows it in trigger cycles:

1*R = (1*hp regened)/(256*frames)
128*R = 128[ (1*hp regened)/(256*frames) ], multiplied both sides by 128
128*R = 1*hp regened/(2*frames), simplified
128*R = 1*hp regened/(1*trigger cycle), substituted trigger cycles for frames
R = 1*hp regened/128*trigger cycle, divided both sides by 128
or R = hp regened/128trigger cycles

Now we can substitute this into the first equation

R = ceil[ .9 * H / B ]
(1*hp regened)/(128*trigger cycles) = ceil[ .9 * H / B ]

Now we can plug in the numbers you want, 100 hp regenerated, and 65 trigger cycles

(1*100)/(128*65) = ceil[ .9 * H / B ]
5/416 = ceil[ .9 * H / B ]

Curiously, ceiling (rounding) is not a reversible operation, at least not from my understanding, so imma just ignore it (we can make little adjustments later)

5 / 416 = (.9 * H) / B
B * ( 5 / 416 ) = .9 * H
B = ( .9 * H ) / ( 5 / 416 )

---

B = ( .9 * 4800 ) / ( 5 / 416 ) = 359,424 build time
B = ( .9 * 650 ) / ( 5 / 416 ) = 48,672 build time
B = ( .9 * 416 ) / ( 5 / 416 ) = 41,184 build time
B = ( .9 * 330 ) / ( 5 / 416 ) = 24,710 build time

Try those build times out.

I know nothing of repair costs, pass me some links if you need help with that.

I'm not sure where the error is, but you will actually want to divide all of those build times by 100.
359,424 build time -> 3594
48,672 build time -> 486
41,184 build time -> 411
24,710 build time -> 247

Wow what a headspin! What does "ceiling" or "rounding" mean? And thanks guys, this has helped.

Ceiling is basically bringing the number up to the nearest upper whole number (e.g. the ceiling of 1.1 is 2, the ceiling of 0.9 is 1).

100 HP in 65 trigger cycles gives a build rate of 197 = (100*256) / (65*2)
If you solve the equation for Build Rate:
0.9*H/R = B

I get these build rates:
5614
761
644
386

Cost is linear as well, but I don't recall how to get that to work. If you feel like experimenting, just get a bunch of data (you can post it here if you want) and plop it into excel. Make 100 vultures, damage them at various rates, then heal them all the way up to 100% and note how many minerals it took. Eventually you'll get the repair cost formula.

Alternatively, just heal one thing to 100% from 1% and you should have a good guess. If repairing a barracks (150 minerals) to 100% costs 50 minerals, then you know the repair cost is 1/3 total cost (I think this is the case)

Just tested in scmdraft, these are the correct numbers!

Post has been edited 4 time(s), last time on Jul 3 2013, 6:15 am by Leeroy_Jenkins.

Tried everything I could think of to get from this:


to this:


and it doesn't seem to coalesce, could you (rockz) post how you're defining R so the wiki can be updated?

197/256 hp/frame = 100hp / 65*2 frames

I multiplied the 256 to the other side, since HP is a 4 byte variable but you only see 3 bytes of it.