Messages

121

Off Topic / Statistics Question

« on: May 28, 2005, 03:00:17 PM »

Here's my try on the problem.

If B, C, D, E are independent and A=(B||C||D||E), then ~A=~B&~C&~D&~E (note: '~A' means 'not A') and P(A)=1-(1-P(B))(1-P( C))(1-P(D))(1-P(E)). To change P(A) and conserve the relative probabilities of B, C, D, E, you need to solve a quartic equation.

But I think it would be simpler to define a as the expectation value of the number of events. In that case a = P(B)+P( C)+P(D)+P(E) and it's straightforward to rescale the probabilities.

122

Suggestions / Make position a Single, not a Long

« on: May 23, 2005, 11:46:25 AM »

In VB, the largest number that can be held in a single precision floating point variable is 32767.

:blink:  :blink:

Please try

Code: [Select]

Private Sub Command1_Click()
Dim count As Single
While count < 400000000#
 Print count
 count = count + 10000
Wend
End Sub

123

Bugs and fixes / inc and dec cost energy

« on: May 23, 2005, 07:14:34 AM »

Please check by yourself. For instance with a dummy bot like

Code: [Select]

cond
start
50
inc
stopand a high store cost. Note that there's another quirk: the actual store cost is 1/5th of what is displayed in the Options tab.

124

Suggestions / Make position a Single, not a Long

« on: May 22, 2005, 08:46:36 PM »

What do you mean by 'too big for a single to cope with'? Larger than 3.402823E38?? :blink:

Concerning the crashes, I suspect what happened was the following: you tried to fit x^2 into a Long with x>32768 by writing

Code: [Select]

Dim d As Long
d=Sqr(x^2+y^2)
Concerning the robots, I don't see why their CPU needs to work with anything larger than an integer.

One more thing: I don't see the connection between the robots' memory and their position. They don't know their (x,y) coordinates nor should they.

125

Tips and Tricks / Do you know what is venom?

« on: May 22, 2005, 08:22:42 PM »

I'm sorry but I find your explanation contradictory with the premise of DB. If animal species tend to be immune to their own venom (I think it's not the case for scorpions, by the way), it's because they have evolved so. Actually, I suppose they have either co-evolved their efficiency at producing venom and their immunity or become immune and then started producing venom. Anyway, DB is not about sea slugs fighting each other, it's about evolution, sea slugs being only one of the (hopefully) possible results.

126

Bugs and fixes / inc and dec cost energy

« on: May 22, 2005, 07:59:50 PM »

Looking through the code, I was fairly surprised to discover that

Code: [Select]

a incis (almost) exactly equivalent to

Code: [Select]

*a 1 add a storeThis means that contrary to what is stated everywhere I've looked, inc and dec cost exactly as much energy as store.

127

Suggestions / Make position a Single, not a Long

« on: May 22, 2005, 06:08:32 PM »

I don't see any reason why robots' coordinates should be integers. In the current code, there's a lot of back and forth conversions between Longs and Singles. Eliminating those should reduce the probability of errors.

128

Tips and Tricks / Do you know what is venom?

« on: May 22, 2005, 05:35:04 PM »

And the third is mine. I've looked at the code but I don't really understand the logic. Why are robots of the same species immune to venom? IMHO, species is only a convenient label but shouldn't have any in-game effect.

129

Newbie / Hi!

« on: May 19, 2005, 07:43:14 PM »

V2.35 was an example of that. Something in the ties got screwed right up (phantom ties to nothing and weird long ties going across the whole screen)

I've seen something like this when trying to modify the collision routines. Switching all private variables to Single seems to have cured it.

130

Newbie / Hi!

« on: May 18, 2005, 09:01:37 PM »

The collisions are actually much simpler now.
The "repel" routine has been ditched in favor of a system which uses conservation of momentum. This make more sense as bots are different masses now.
Runs faster too.

Great! Though I wish you'd told me this before I decided to rewrite repel.

It is necessary for it to have a mass of 1/2 to acheive this. That means no shell and a body of 20.

Code: [Select]

.mass = 1 + (.body / 10000) + (.Shell / 200)Or has it changed as well ?

So whatever you can figure out in the 2.36.5 code should hold true for everyone.

Well... mostly I figured that the code is more readable when unused procedures and commented out bits of code are deleted and that every time you fix something, you create a new source of crashes.

131

Bugs and fixes / Children Are Immune to Parent's Shots

« on: May 18, 2005, 10:25:25 AM »

Yes, that is a recent change, and is mostly there to prevent a parent from injuring a child if it reproduces while firing a continuous stream of shots.

IMHO, this is wrong. A bot that shoots its child deserves to get extinct.

132

Newbie / Hi!

« on: May 17, 2005, 06:45:53 AM »

Well... the artificial cap is on momentum, not velocity. It's not fundamentally different.
I'll try to make concrete suggestions when I understand the code better.

A question: how can I get the latest version of the code?

133

Newbie / Hi!

« on: May 16, 2005, 07:19:21 PM »

Interesting! Physics at low Reynolds number is definitely weird. This might be an interesting option, though I don't really know how to program it.

However, I know that the environment could be anything but fluid friction has the advantage that there is a physical maximum velocity (well, depending on the force created by the bot...) To me, this feels better than having an artificial cap.

134

Newbie / Hi!

« on: May 16, 2005, 05:19:24 PM »

Sorry, my first post sounds much more critical than I intended. The thing is, I'm mostly interested in evolution sims and I was a bit disappointed to see that this part of the program didn't seem much improved. What I'd like to see would be vegetables that can evolve without predators (I.e. that can compete between themselves for something else than space), viable evolution for multibots, etc.

Anyway, the actual changes I'd like to make would mostly be to make the code read better, so that the logic becomes more apparent. Separate clearly what happens inside the robots from what happens outside, find a way to not use robots to make corpses and walls, etc.

Concerning the physics, the most obvious incoherence is that we have solid friction even though bots are supposed to live in water. Fluid friction (I.e. proportional to velocity) would make more sense. I haven't yet understood all the code, but it's written in such a way as to make me feel there must be mistakes. Perhaps there aren't, but rewriting it would make it is possible to understand and modify it.

PS: the version I have is 2.36.5, from the FTP server.

135

Newbie / Hi!

« on: May 16, 2005, 12:30:19 PM »

Hi all! I've actually discovered DB a long time ago (Autumn 2003) but I played with it only for a few weeks and then I shelved it. I'd like to help with the code. I've already had a look at it and, frankly, it's a mess! The physics model is quite weird and, IMHO, should be brought more in line with reality.

So, may I meddle with the code and if yes, how can I submit changes to the code and where do I start?