New Cost coming in 2.42.2

[Numsgil]

A short article I found (if you avoid all the ones on creationism) about death;

Natural selection: Evolution of lifespan in C. elegans
DAVID W. WALKER1, GAWAIN MCCOLL1, NICOLE L. JENKINS1, JENNIFER HARRIS1 & GORDON J. LITHGOW1
School of Biological Sciences, University of Manchester , Manchester M13 9PT, UK
e-mail: Gordon.Lithgow@man.ac.uk

It was proposed almost 50 years ago that ageing is non-adaptive and is the consequence of a decline in the force of natural selection with age. This led to the theory that ageing results from detrimental effects late in life of genes that act beneficially in early life, so any genetic alteration that increases lifespan might be expected to reduce fitness, for example. We show here that a mutation that greatly increases the lifespan of the nematode Caenorhabditis elegans does indeed exhibit a fitness cost, as demonstrated during starvation cycles that may mimic field conditions, thereby validating the pleiotropy theory of ageing.

Jez

[PurpleYouko]

Whatever happened to good old Jez?

sigh....

[Endy]

The thing about life is that it's real goal is only to survive. In the real world everything has its entropy increase over time, based on how active it is. Eventually the cost of entropy will kill anything, therfore life reproduces to reset its entropy level. In DB we don't have this restriction to a noticable extent, so we have these insanely long lived bots. Essentially they become immortal and have no reason to reproduce since it will only decrease their own chances for finding food and possibly being attacked by their own decendents.

Maybe have Entropy Cost rise based on both Age and Pwaste/Waste. Overall Age would increase it slightly while Pwaste would increase it faster. This way all bots will eventually die, but bots that choose to "live fast" would age faster than more restrained counter parts.

Changing Enviroments:

Maybe add something like scripting for the enviroments. A way to gradually alter the entire enviroment within a selected range would be really cool.

[EricL]

In the real world everything has its entropy increase over time, based on how active it is.

This is known as the "Rate-of-Living" Theory of Aging and has been shown to be patently false.  The relationship between lifespan and metabolic rate varies widly in nature and there are lots of experiements which show that you can artificially select for longer lifespan in the organism of your choice and that doing so has little or no impact on metabolic rate.  

Additionally, even if entropy was some sort of the intrinsic aspect of systems that could accumulate over time like some sort of byproduct (its not) the 2nd law of theremodynamics only applies in closed systems.  Neither the earth nor DB are closed systems.

I will add an optional cost related to robage in 2.42.2 so that people who want the system to tax age can do so, but theories which say that limited lifespan is somehow intrinisic and externally dictated becuase of physics or something are IMHO, incorrect.

Maybe add something like scripting for the enviroments. A way to gradually alter the entire enviroment within a selected range would be really cool.

Completly agree.  This won't be in 2.42.2 however  

[Numsgil]

I would recommend a logarithmic relationship between age and cost, so that you aren't really creating a ceiling age as much as slowly taxing the elderly.  Just my thought on the matter, feel free to take it with a grain of salt.

[EricL]

Okay, I have implemented two new age related costs, available on the Advanced Costs dialog in the forthcoming 2.42.2 release. The first, Age Cost (const AGECOST in the code) allows the user to specify a value which will be multplied times the log of the robots age to determine the cost per cycle in nrg to charge the bot. The second (const AGECOSTSTART in the code) is less of a cost and more of a trigger value which determines at what age in cycles to begin charging the Age Cost.

The combination of the two should provide some flexability for those interested in imposing costs on aging or specifying a specific lifespan.  If you want to gently increase the cost as the robot ages, specify a low value in the Age Cost and begin charging the cost when you want, even from birth.  It will gently increase over the lifespan of the bot as a function of the log of the age.  Efficient bots may still live a long time in this mode and be able to overcome the tax.  If you want a more severe cost to be applied at a specific age, specify a high number in for the Age Cost but don't begin charging it until the robot age you prefer.  This will start taxing the bot rather suddenly and severely once it reaches the specified age.

Note that no matter what age you begin charging the Age Cost, the value Age Cost is mutliplied by once you begin charging it is the log of the robots full age, not the log of the full age less the trigger age.  If there are stong opinions on this, I can change it.

I did consider fancy solutions where the Altzheimer's probability could be increased with age or where the age cost actually increased the values of other costs over time but decided to keep it simple for now.

[EricL]

I changed this a little bit by adding a check box which allows the user to specify whether they want the Age Cost to remain constant or to increase as a function of the log of the bot age.  Thus these new Age related costs can replace the nrg/cycle cost of being alive work I had implemented earlier.  See #15 and #20 in the first post in this Topic:  Stuff in 2.42.2