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v0.31:Animal logic
| This article is about an older version of DF. |
Animal logic functions by taking advantage of the path finding algorithm in Dwarf Fortress; all animals seek to find the shortest (lowest cost) path to their desired targets (activity zone, parents, dwarfs, valuable objects, etc), this can be used to create very very complex logic gates. Animal logic has three principal advantages: speed, compactness, and simplified functions. However, animal logic is slower than mechanical logic and less reliable than either fluid or mechanical logic.
Definitions
For clarity, definitions of the terms used in animal logic are listed here:
Ground: for simplicity the thing the animal is pathing to is referred to as ground as that is the ground state which it wishes to reach. Ground is always the left unless otherwise noted.
Purge: Path to ground with no inputs
Path cost: The number of steps the animal must make to reach ground
Fusion Gate: Simply one or more logic gates built into the same system (this is more than simply stringing gates)
Compound Gate: Gate which uses two or more gates set to different path costs.
AND Gate: AND takes 2 or more inputs and returns TRUE if ALL are TRUE.
NAND Gate: NAND takes 2 or more inputs and returns TRUE if ANY are FALSE.
ANDOR Gate: ANDOR takes 2 ore more inputs and returns TRUE if X-Y are TRUE. (this gate is exclusive to animal logic, and is a single step fusion of AND and OR)
OR Gate: OR takes 2 or more inputs and output TRUE if ANY are TRUE.
NOT Gate: NOT takes a single input and inverts it to the opposite state.
XOR Gate: XOR takes 2 or more inputs and output TRUE if ANY are TRUE but NOT ALL are TRUE.
NOR Gate: NOR takes 2 or more inputs and returns TRUE if ALL inputs are FALSE.
XNOR Gate: XNOR takes 2 or more inputs and returns TRUE if ALL are TRUE, or ALL are FALSE.
For a better explanation of gates see:http://en.wikipedia.org/wiki/Logic_gate
Notation: #:always wall ^:pressure plate X:floodgate,grate,bars,bridge,etc(explained per entry) D:door,open, but kept tightly shut(pet impassable) d:door, input value not specified Letters:doors/floodgates,grates,bar,etc Specified inputs(these are generally interchangeable, if not this will be noted in the entry) g:Ground, some entries need it for clarity. C: Either an input in diagrams, or the state Carry is refereed to as a state within an adder.
Gates will always be capitalized in the way they are within the entry, e.g. AND, OR, ANDOR, XNOR, etc.
The basics of construction for an animal logic takes advantage of an animal's tendency to continue to path through tightly closed doors, despite them not being able to pass. It goes without saying that all doors not wired to mechanisms need to be tightly closed.
There are three principal logic gates in any logic system, AND, OR, and NOT. Animal logic can easily create all logic gates and is able to handle multi input-output, and fusion gates. The principal reason for this is pathfinding always prefers the shortest path to ground, and by controlling this path you can control the animal within the gate. The advantage of animal pathing is that the gate can have multiple states allowing more than a single ON or OFF signal. For simplicity and streamlining these systems only use binary information, but theoretically they could be made to compute in decimal or some other system; however, such gates are maddeningly complex and very hard if not impossible to build.
SIMPLE GATES
There are two primary ways to make a gate, single path and dual path, the single path gate only allows the animal a single exit and this forces it into a non pathing state until there is input at which point it will "wake up" and move; however, this kind of gate is slow and unreliable. Dual path gates always have an open path keeping the animal constantly pathing out of its enclosure. This constant pathing allows the gate to respond more quickly and retain higher reliability; however, the constant pathing may cause noticeable frame rate drops with large logic sets. I will only be discussing the dual path gates, as they're more effective for general use.
AND
This simple gate is made by confining the animal into a straight coridor; the ground path will have two or more doors which are connected to the input, while the second longer path remains clear. The gate can be configured as an NAND gate by simply moving the pressure plate. If the plate is by the ground path it functions as an AND gate returning TRUE if the ground path is open, and if the plate is by the purge path it will return FALSE when the inputs are TRUE.
######### ABCD^ D #########
Multi AND
############ ANYNUMD^ D ############
NAND
Reconfigured AND gate, see Template:L.
######### ABCD ^D #########
OR
Basic gate, returns TRUE if either input is TRUE.
##### AD^ D B#### #####
Multi OR
####### A ##### N ##### Y D^ D N ##### M ##### #######
NOR
Basically a reconfigured OR gate
##### AD ^D B#### #####
NOT
The simplest gate, it takes a single input and inverts it. FALSE -> TRUE, TRUE -> FALSE.
####### AD ^D #######
Compound Gates
Basically two or more gates arranged with different path costs to ground. These gates can be configured in a number of different ways, these being the simplest. It may be possible to make these gates as single gates but that would require inverting some of the input. Simple compound gates use two simple gates and handle two inputs, complex compund gates have more then two simple gates and need more than two inputs. a Complex compound gate might be used to convert decimal numbers into binary using And gates.
XOR
Compound of AND and OR, when ONLY ONE is TRUE returns TRUE If A and B are FALSE the animal moves to the FALSE position by Purge, if A or B is TRUE, the animal moves to the TRUE position at the OR gate, if both A and B are true the animal moves to the FALSE position by the AND gate.
#g######## # ABD D # # ####^# # # ####D# # # ###BA# # # # ##########
AND path cost: 4 OR path cost: 10 Purge path cost: 14
XNOR
Inverse of XOR: Return TRUE if BOTH are TRUE or FALSE If A and B are FALSE the animal moves to the TRUE position by Purge, if A or B is TRUE, the animal moves to the FALSE position at the OR gate, if both A and B are true the animal moves to the TRUE position by the AND gate.
#g######### # # ##B###### # ###A## DA # ####D^##B # #####D### # ###### # ###########
AND path cost: 4 OR path cost: 10 Purge path cost: 15
Complex Compound gate, Octal display ALU
Inputs are 1,2,4 these correspond to the binary values of the inputs, outputs are A,B,C,D,E,F,G,H being 0,1,2,3,4,5,6,7 respectively in the output display. I used octal for sanity, but this could be easily scaled to work for decimal (up to 10, beyond that you need a converter not an if switch) or hexadecimal(hex will be easy to handle, and probably easier to convert down to decimal)
#################
#
# # # # # # #1# #
# # #1# #1#2#2# #
#1#2#2#4#4#4#4# #
#D#D#D#D#D#D#D#D#
# #
#################
# ###### # 1 D # # #### # # 2 D # # #### # # 12 D # # #### # # 4 D # # #### # # 14 D # # #### # # 24 D # # #### # # 124D # # #### # # D # ########
Fusion gates
These are gates which are constructed by physically combining the two gates to get a specific output.
ANDOR
This gate will evaluate if either of x AND statements are TRUE. This gate is built as a straight line similar to the And gate
###### #C#### ABD^ D C##### ######
NANDOR
Reconfigured ANDOR gate, see Template:L.
###### #C#### ABD ^D C##### ######
OrandOr
This gate returns true if either A or B and either C or D is true.
###### AC#### BED^ D ######
OrandAnd
This gate returns true if either A or B is true, and E and C are true.
####### A###### BCED^ D #######
Complex Gates
The development of more complex gates requires carful calibration of the path cost of each path to allow the gate to switch states correctly and display the correct result.
Adders
A Full adder can be made as a Compound Fusion gate, by combining, And, AndOr, and Or gates
Binary Adder
A binary adder is constrcuted of two or three "sum" gates and a purge path. a half adder only adds two numbers and only needs two sum gates, 1 and 2. Full adders using carry to allow chaining require three sum gates, 1,2 and 3. Because binary is base two that translates to 01,10,11 as the sums, when the second bit is a 1, the gate is "carrying" the value up to the next level.
An building the adder the highest path must have the most preferential path to ground or it will not properly function.
Standalone Adders (they don't carry into another adder) require 22 mechanisms, and 14 doors. Start Adders (They feed into the next Adder and include a carry) require 32 mechanisms, and 14 doors. Chain Adders (The receive Carry, and pass a Carry bit up) require 32 mechanisms, and 14 doors While Materials intensive the gates only take up 13x9 urists, ideal for chaining along mining tunnels.
Reference pictures
Prototype digital adder
sum 11
sum 10
sum 01
sum 00
9bit adder interface
9bit adder
9bit adder, notes show the decimal value of each adder's bit
Decimal Adder
While it can be done, it's significantly more complex than simply making a set of decimal converters working with binary adders.
Hexadecimal Adder
A hexadecimal adder works on a similar level to the binary adder, however it uses 64 sum gates ranging from 0 to 31. User:LordOOTFD is developing a prototype adder which utilizes a floating carry bit to function as a full adder.
Subtractors
Inverse adder, simple but not yet tested.
Animals
Choosing the animal which works as the logic core for an animal logic systems is somewhat important, depending on your needs and the available animals. However pretty much anything will do as long as you can remember which animal fits into which gate (to avoid designating the same animal for more than one pit).
Kittens
While kittens are the most reliable cores for logic gates because of their three pathing goals they're also problematic as they grow into cats which only have two, and may cause catsplosions inside your logical cores. Ideally kittens should be replaced yearly or biyearly as their growth defines. Kittens path to the activity zone, their parents, and vermin.
Puppies
Puppies are quite reliable with Two pathing goals, but retain the problem of maturation. Puppies path to the activity zone, and their parents.
Animal Children
Using the non matured animals for something useful before butchering may be quite effective, however they still must be flushed when they mature. Animal children path to the activity zone, and their parents.
Cats
Aggravating animals, throw them into the computer and get some worth out of them. Otherwise useless cats become useful when used for logic, with two pathing goals they're responsive, and multiply quickly. Watch out for catsplosions while using these critters Cats path to the activity zone, and Vermin.
Dogs
While dogs may seem an attractive option for logic cores, they will be far more useful as wardogs or hunting dogs to protect dorfs. Dogs path to the activity zone.
Cattle
Large lumbering bovines, the advantage of Cattle is you can tell the sexes apart, they also make the pressure plates continue to work even if you forget to reassign the trigger weight. Cattle path to the activity zone.
Other animals
Any animals work, but the above are probably your best choice, excluding any modded animals. however if you have a GCS handy a GCS powered computer would be awesome, so take this as you will. Other animals have different pathing goals, but most only path to the activity zone.
Goblins
Goblin powered logic is highly ironic, especially if it involves controlling your goblin killing magma trap.
Putting it all together
When it comes time to automate your systems the first thing you need to know is what needs to be automated and what should remain manual. An obsidian farm with completely autonomous control of the casting process is all well and good, until it drowns all your legendary miners when it prematurely triggers. All systems should have manual controls and failsafes to help avoid Template:L (but because we all love Fun sometimes you forget to fully connect that emergency drain, or that failsafe system you built somehow failed.)
Once you know the steps you need in your system, it comes time to select the parts you need to automate, whether it be basic logic gates or more sophisticated multiple trigger systems.